III. ECOLOGICAL RELATIONSHIPS (continued 2)

It is common knowledge among those who rear cockroaches experimentally that, unless the water content of the food is high, fluid water is essential in the insects' dietary. Ten species of domiciliary cockroaches have been shown to be unable to survive as long on dry food alone as they could on food and water at 36-40 percent relative humidity (Willis and Lewis, 1957). Blatta orientalis, when in a state of normal water balance, usually spent more time in the drier part of a humidity gradient; but desiccated insects tended to become hygropositive (Gunn and Cosway, 1938). We presume that other domiciliary species behave similarly. If water is available nearby, it may be presumed that partially desiccated cockroaches could locate a source through the mediation of a humidity sense. Hygroreceptors have been demonstrated on the antennae of Blattella germanica (Roth and Willis, 1952a) and suggested for Blatta orientalis (Gunn and Cosway, 1938).

Drinking water is available to cockroaches in the traps of sinks, wash basins, tubs, and toilet bowls; in flush tanks; as condensation on cold pipes, flush tanks, and windows; around leaking pipes and faucets; as spillage; in miscellaneous water-filled containers, such as pet drinking dishes, aquaria, vases; empty beverage bottles; and drainage from ice boxes. Soft, juicy fruits and vegetables can provide both moisture and food. There seems to be a tendency for certain species (Blatta orientalis and Blattella germanica) to become established in the more humid parts of structures, such as basements, around sinks, and in bathrooms. Whether this is a reaction to a preferred humidity or merely a fortuitous aggregation near sources of drinking water and food has never been clearly demonstrated. The rather widespread dissemination of these species into zones of low as well as high humidity suggests that detailed studies of the microclimatic conditions of structural microhabitats will be needed before meaningful conclusions can be drawn about the stratification of cockroaches within structures according to species.

In nearly all structures infested by cockroaches, food of some kind is available, either in the structure itself or nearby. This may be the food stored by man for his own use or the use of kept animals; it may be crumbs, food spillage, garbage, or excreta; glues and pastes on cartons, boxes, stamps, envelopes, labels, and wall paper; sizing on cloth and book covers; various dried animal and plant products; dead insects; living plants; etc. In fact, it is almost impossible, despite good housekeeping, to keep any structure used by man free of all food suitable for cockroaches.

That the requisite temperature, water, and food are provided, more or less adequately, by a variety of structures is attested by the innumerable infestations of cockroaches that develop when control measures are relaxed. Within structures the accessibility of certain harborages to cockroaches probably depends on the habits of the species and to some extent on their size. Similar types of harborages in different structures may be used by the same species, although there seems to be some overlapping by different species into the same kinds of daytime shelters. The comparative ecology of domiciliary cockroaches has not been thoroughly investigated, so any interpretation of observational data is necessarily speculative and inconclusive at this time. Our discussion on pages 324 to 343 is also pertinent to this section.

LAND-BASED STRUCTURES

Dwellings provide a variety of microhabitats that are acceptable to cockroaches. It has been stated that old houses, or houses that have many cracks and crevices, or have basement kitchens that are not kept clean and in good repair are particularly liable to invasion by cockroaches (Laing, 1946; British Museum [Nat. Hist.], 1951). Although this statement is undoubtedly true, it has been our personal experience, as well as the experience of others, that new, clean, and well-planned houses and apartments are also easily and sometimes quickly invaded by cockroaches. Mallis (1954) has cited the following places that are frequently infested by cockroaches in homes. In the kitchen, cockroaches are found in and around sinks, in cupboards above and below sinks, under tables and chairs, in stoves, around breadboards, in utility cabinets, in kitchen closets, under linoleum, behind, under, and inside refrigerators and iceboxes. In living rooms cockroaches are found in furniture, studio couches, sewing machines, closets, and bookshelves; behind picture frames, pennants, calendars, and other wall ornaments. In bathrooms cockroaches are found in and behind utility cabinets and toilets; they may be found in wicker clothes hampers, in brooms and mops, and in door hinges. Ordinarily, cockroaches are not found in bedrooms unless they are abundant elsewhere in the dwelling. Additional harborages are cited under specific cockroaches in the list below.

In markets DeLong (1948) found the German cockroach in bags of potatoes and onions, in crates of citrus fruits, in pads and shredded papers in banana boxes, and in cases of bottled beverages. The insects were attracted by coffee and crawled into the folds of coffee bags. They were found in cartons of canned goods; in bread and baked goods; in cartons of packaged cookies, cakes, and crackers. Packaged cereals were attractive, and cockroaches were sometimes found in packages of cigarettes. The insects occurred in scales (by the hundreds) and in cash registers. Rather heavy infestations were found under stainless-steel cappings that covered wooden arms on the fish cleaning stand. The insects were numerous in display cases where they were warm and sheltered. They were also found behind mirrors above produce racks, in electrical switch boxes and conduits, and in telephone boxes, as well as generally in cracks and behind loose moldings or loose wall boards. Enclosed boxlike tables were frequently heavily infested.

In restaurants cockroaches may be found in the following places: Crevices in wood, plaster, concrete, and metal; in the bar; in the kitchen and in the associated equipment; in cupboards, lavatories, and garbage storage areas; and on the undersides of chairs and tables (Mallis, 1954).

In drug stores Frings (1948) found cockroaches behind the mirror and between the sink and the cooler. Thousands were found in hollow ornamental shelf edging. The hollow bases of malted-milk dispensers and drink mixers were cockroach havens.

In a hospital Frings (1948) found cockroaches in decorative trim around doorways, by the thousands in wicker laundry baskets, and in incubators for premature babies. In military hospitals we have seen cockroaches (Blattella germanica) in kitchens and dining halls in the usual hiding places mentioned above and on the undersides of stainless-steel serving tables.

In department stores cockroaches have been found in food departments, beauty salons, rest rooms, dressing rooms, linen departments, and stationery departments (Anonymous, 1952). The infestation in the linen department was traced to clean towels which, when returned from the laundry, contained at least 500 cockroaches per bundle. The insects were carried into the rest rooms and beauty salon when the towels were distributed.

The microhabitats of cockroaches in privies and sewers have not been studied. These habitats are particularly important in view of the demonstrated migrations of cockroaches from sewers into dwellings and the possible dissemination of pathogenic microorganisms from feces to food. The reader is referred to our 1957(a) paper for a summary of the known information on cockroach dispersal from sewers.

COCKROACHES ASSOCIATED WITH LAND-BASED STRUCTURES

Most of the cockroaches listed below are either known domiciliary species or they have been found one or more times in houses or other man-made structures. The known structural pests breed within the building. Certain other species, which have been observed only infrequently in structures and are not known to breed there, may possibly be incipient pests; these latter species may attain future economic importance if they establish breeding colonies within a structure. A few species have undoubtedly wandered indoors by accident. It is difficult to decide whether a particular species was an accidental invader or whether it was attracted indoors in response to some stimulus. Only additional information will provide the desired answers.

Aglaopteryx ypsilon

Trinidad.—Male found indoors (Princis and Kevan, 1955).

Allacta similis

Hawaii.—Found only indoors at Nauhi. Otherwise this is apparently an outdoor species (Swezey and Williams, 1932).

Blaberus craniifer

Cuba.—Household pest (Deschapelles, 1939). Particularly abundant in houses in Santiago and Havana (Rehn and Hebard, 1927).

Florida.—Under boards in woodshed (Rehn and Hebard, 1912, 1914).

Blaberus discoidalis

Ecuador.—In eating places (Campos R., 1926).

Hispaniola.—In houses (Rehn and Hebard, 1927).

New Jersey.—In greenhouse (Weiss, 1917).

Puerto Rico.—In homes (Seín, 1923). In fruit stores (Wolcott, 1950).

Blatta lateralis

Central Asia.—Household pest, often found in homes with clay floors (Bei-Bienko, 1950).

Turkmen S.S.R.—Males and females occurred in dwellings (Vlasov, 1929).

Blatta orientalis

This species is a cosmopolitan domiciliary pest (Hebard, 1917; Rehn, 1945). It is reported to occur particularly in basements and crawl spaces under basementless houses (Mallis, 1954). In damp basements where food is available large colonies are not unusual, but it also may infest offices and apartments several floors off the ground (Gould and Deay, 1940). The number encountered on upper floors is seldom large, but the frequency of occurrence may reach 30 percent of the observations (Spear et al., in Shuyler, 1956). In supermarkets this species hides during the day inside concrete blocks or cracks in the foundation, under furniture, or behind cartons; it is conspicuous on the floors of the markets at night (De Long, 1948). In Great Britain the kitchen is preferred by this pest (and by Blattella germanica); they shelter beneath steam radiators and gas stoves, behind hot-water pipes, underneath furniture and floor coverings, sinks and baths; basements and underground kitchens are especially likely to be infested (Laing, 1946; British Museum [Nat. Hist.], 1951). Goodliffe (1958) noted that B. orientalis may travel long distances to find food.

Blattella germanica

This species is a cosmopolitan domiciliary pest (Hebard, 1917; Rehn, 1945). It is one of the commonest insects in homes and restaurants (Gould and Deay, 1940). It is found in kitchens, larders, bathrooms, furnace rooms, and storage rooms of bakeries, breweries, hospitals, barracks, as well as dwellings, where, during daylight, it hides behind cupboards, furniture, hanging pictures, panels and skirting boards, in cracks around drains, water pipes, electric wires, and hot-water and steam heating units (Wille, 1920). The German cockroach may be found in cracks around baseboards, pipes, conduits, sinks, and drawers; behind cabinets; inside switch boxes and refrigerators; on under surfaces of tables, chairs, and shelves; between stacks of stored goods, and in almost every place that is not readily observed (Kruse, 1948). We have also seen this species packed in electric-clock cases and loud-speaker baffles, in cash registers, and clinging to the undersurface of stainless-steel steam tables. The infestation of markets by this species has been described above. Very narrow cracks provide refuges for the German cockroach. Wille (1920) found first-instar nymphs in cracks 0.5 mm. wide and adult males and females without oöthecae in cracks 1.6 mm. wide.

Shuyler (1956) has observed extensions into relatively new structural habitats by Blattella germanica in the north-central area of the United States. A few German cockroaches are now being encountered in living rooms, bedrooms, clothes closets, bedroom furniture, lobbies, entrance halls, checkrooms, nonfood storerooms, nonfood warehouses, and coin-vending machine repair shops. In these situations this species is behaving much like the brown-banded cockroach, Supella supellectilium.

Blattella schubotzi

Cameroon.—Five specimens in a house (Princis, 1955).

Blattella vaga

U.S.A.—Although this is mostly an outdoor species, during dry seasons it may temporarily enter houses in great numbers, occasionally breeding indoors in Arizona (Flock, 1941a). Two adults were collected indoors in Texas (Riherd, 1953).

Chromatonotus notatus

Trinidad.—A male was found indoors (Princis and Kevan, 1955).

Cutilia soror

Hawaii.—Almost as common in houses as Neostylopyga rhombifolia (Hebard, 1922).

Ectobius duskei

U.S.S.R.—Frequently occurs in living apartments in farming localities as an accidental inhabitant (Bei-Bienko, 1950).

Ectobius pallidus

Massachusetts.—A summertime pest in houses along coast (Gurney, 1953; E. R. Willis, personal observation). Generally an outdoor species.

Epilampra abdomen-nigrum

Trinidad.—Male, indoors (Princis and Kevan, 1955). An outdoor species generally.

Ergaula capensis

Cameroon.—A male taken in a house (Princis, 1955).

Eublaberus posticus

Trinidad.—Indoors, feeding on bat feces (Princis and Kevan, 1955).

Eurycotis floridana

Florida.—Occasionally found in homes (Creighton, 1954; Roth and Willis, 1954a).

Euthyrrhapha pacifica

Hawaii.—Found outdoors and indoors where it breeds in neglected cupboards and in rubbish (Fullaway and Krauss, 1945).

Holocompsa azteca

Mexico.—Household pest (Ball et al., 1942).

Holocompsa cyanea

Costa Rica.—One specimen in house (Rehn, 1906).

Holocompsa nitidula

Apparently domiciliary in American Tropics (Hebard, 1917). In houses under chests, etc., Cuba (Gundlach, 1890-1891); Puerto Rico (Gundlach, 1887). In folds of burlap bag, Florida (Rehn and Hebard, 1914).

Ischnoptera rufa occidentalis

Panama.—Thrives about human habitations under litter, though not domiciliary (Hebard, 1920).

Ischnoptera rufa rufa

Jamaica.—In hotel. "While hardly a domiciliary form it would seem to frequent environments where man has considerably disturbed natural conditions, as under debris, docks, under logs and stones in cultivated areas" (Rehn and Hebard, 1927).

Leucophaea maderae

West Indies.—In habitations, warehouses, and other structures; "At times it is a very abundant and serious pest" (Rehn, 1945). In Puerto Rico it was also found in fruit stores, markets, and inns (Seín, 1923; Wolcott, 1950).

Reported as a domiciliary pest in Madeira (Heer, 1864); Windward Islands (Marshall, 1878); Tropics and sub-Tropics (Rehn, 1937); Philippine Islands (Uichanco, 1953); New York City (Anonymous, 1953; Gurney, 1953); Trinidad (Princis and Kevan, 1955). This species is also established in coastal Brazil, Central America, all the Greater Antilles, several other tropical islands, and tropical Africa, where it probably originated (Rehn, 1945).

Leurolestes circumvagans

Hispaniola, Grenada.—Largely domiciliary (Rehn and Hebard, 1927).

Leurolestes pallidus

Cuba.—All over island, in houses, under lockers, etc. (Rehn, 1945; Gundlach, 1890-1891).

Florida.—Rehn and Hebard (1914).

This species has been recorded from various islands in the West Indies, from Mexico, Guatemala, and Brazil (Rehn, 1945).

Methana marginalis

Australia.—Reported entering houses (Pope, 1953a).

Nauphoeta cinerea

Australia.—In hospital (Mackerras and Mackerras, 1948). In dwellings, grain stores, and fowl-feeding pens (Pope, 1953).

Sudan.—Domiciliary in huts of the Shilluk natives; fairly widely distributed in eastern Africa (Rehn, 1945).

Hawaii.—In feed rooms of poultry plants (Illingworth, 1942).

Florida.—Established in feed mills around Tampa (Gresham, 1952; Gurney, 1953).

The wide distribution of this species from East Africa, where it originated, to the Orient and the New World was undoubtedly mediated by shipping (Rehn, 1945).

Neoblattella sp.

Puerto Rico.—Observed [as Blatta caraibea, Rehn and Hebard (1927)] in houses (Gundlach, 1887).

Neostylopyga rhombifolia

Domiciliary in Indo-Malaya and New World Tropics (Rehn, 1945); Philippine Islands (Uichanco, 1953); and Hawaii (Hebard, 1922).

Oxyhaloa buprestoides

Presumably to some extent domiciliary, as it evidently spread from Africa to the New World via slave ships (Rehn and Hebard, 1927; Rehn, 1945).

Panchlora nivea

Colombia.—A male and a female taken in a dwelling (Princis, 1946). This is primarily an outdoor species which is frequently taken indoors as an adventive on bananas (see p. 150 for references).

Parcoblatta fulvescens

Florida.—Males found in laboratory and dormitory buildings, ostensibly attracted by lights (Friauf, 1953).

Parcoblatta lata

Connecticut.—Domiciliary pest (Moore, 1957). Generally an outdoor species.

Parcoblatta notha

Arizona.—It may occasionally be a nuisance in houses (Ball et al., 1942).

Parcoblatta pensylvanica

U.S.A.—Country houses often badly infested, Indiana (Blatchley, 1920). Frequently taken in houses in wooded areas, Michigan (Hubbell, 1922). Infestation by males, females, and nymphs on fourth floor of building, South Dakota (Severin, 1952). Houses in wooded areas infested by nymphs and occasionally by adults (Gould and Deay, 1940).

Canada.—Pest in summer cottages in Ontario (Walker, 1912).

Periplaneta americana

This is a cosmopolitan domiciliary pest (Hebard, 1917; Rehn, 1945). It is common in restaurants, grocery stores, bakeries, and where food is prepared or stored; it was trapped regularly in the basement and upper floors of store buildings, and it was also found in all heated parts of an old meat-packing plant (Gould and Deay, 1938). P. americana was numerous in latrines in Iran (Bei-Bienko, 1950) and in privies in Texas (Dow, 1955) and Georgia (Haines and Palmer, 1955). Large numbers of this species also occur in sewers adjacent to human habitations (Roth and Willis, 1957a).

Periplaneta australasiae

Generally domiciliary, but also occurs outdoors in the West Indies (Rehn and Hebard, 1927). It is a very abundant domiciliary pest in tropical Africa and tropical America (Rehn, 1945); Ecuador (Campos R., 1926); Puerto Rico (Sein, 1923); Philippine Islands (Uichanco, 1953); Australia (Pope, 1953).

Also occurs as a pest in greenhouses in Pennsylvania (Thilow and Riley, 1891); France (Giard, 1900); Italy (Boettger, 1930); Great Britain (Laing, 1946; British Museum [Nat. Hist.], 1951).

Periplaneta brunnea

Circumtropical domiciliary pest which is apparently more nearly peculiar to the Tropics and adjacent regions than P. americana (Hebard, 1917). This species has been trapped in significant numbers in privies and dwellings in Georgia (Haines and Palmer, 1955). It is the species of Periplaneta present in homes in San Antonio, Texas (Mallis, 1954).

Periplaneta fuliginosa

U.S.A.—Frequently encountered out of doors, but has been reported common after dark about a hotel in Alabama and was captured in a house in Louisiana; it was also extremely abundant on the wharves at night in Jacksonville, Florida (Hebard, 1917). As a domiciliary pest it was, next to Blattella germanica, the most common cockroach inside homes in southwest Georgia, where it was also the most common cockroach in privies (Haines and Palmer, 1955). This species has become a very common domiciliary pest in Texas (Eads, personal communication, 1955). It infested a greenhouse for five years in Indiana (Gould and Deay, 1940).

Periplaneta ignota

Australia.—It occurs in dwellings occasionally (Pope, 1953).

Phaetalia pallida

Colombia.—Three specimens from three dwellings (Princis, 1946).

Trinidad.—Male indoors; male and female at light (Princis and Kevan, 1955).

Plectoptera dorsalis

Puerto Rico.—According to Gundlach (1887) it enters houses at night attracted by light (Rehn and Hebard, 1927).

Polyphaga aegyptiaca

Iraq.—Common in houses (Weber, 1954).

Caucasus.—Winged male in kitchen (Burr, 1913).

U.S.S.R.—Listed as a sinanthrope (Bei-Bienko, 1950).

Polyphaga saussurei

South-central Asia.—One of the commonest domiciliary species (Bei-Bienko, 1950).

Pseudophoraspis nebulosa

East Indies.—This species is sometimes difficult indoors (Karny, 1925).

Pycnoscelus surinamensis

A household pest in the East Indies (Karny, 1925); Philippine Islands (Uichanco, 1953); Tanganyika (Smith, 1955); Trinidad, eight records indoors (Princis and Kevan, 1955). It is also a greenhouse pest (Hebard, 1917; Zappe, 1918; Doucette and Smith, 1926; Saupe, 1928; Roeser, 1940). Common in or around chicken batteries and yards in Hawaii (Schwabe, 1949).

Supella supellectilium

Domiciliary wherever distributed (Rehn, 1945), this species is especially difficult to control because of its apparently nonselective dispersal throughout dwellings. For example, Mallis (1954) observed in Texas that it was widely distributed throughout the apartment and was probably the most common cockroach seen in the bedroom; its favorite harborages were beneath and behind corner braces on kitchen chairs, underneath tables, behind pictures and other objects on walls, and in shower stalls; its oöthecae were commonly fastened on walls and ceilings throughout the house. Gould and Deay (1940) reported that this species prefers high locations, such as shelves in closets, behind pictures, and picture molding; oöthecae were found about kitchen sink, desks, tables, and other furniture, and even in bedding. Hafez and Afifi (1956) stated that the adult wanders in nearly all rooms of the house and only visits the kitchen when searching for food; it hides in cupboards, pantries, closets, bookshelves, drawers, and behind picture frames; the nymphs normally hide in the corners of drawers, behind frames, and in similar situations.

Symploce bicolor

Puerto Rico.—In houses, Sardinera Beach, Mona Island (Ramos, 1946).

Symploce hospes

North American Tropics.—Domiciliary, but not exclusively so, and apparently widely distributed (Hebard, 1917). In Florida, as Ischnoptera rufescens, found in a greasy cupboard (Rehn and Hebard, 1914).

Hawaii.—Illingworth (1915).

SHIPS

Sailing ships have long been notorious for their unwelcome hordes of cockroaches, and it was by ship that at least 11 domiciliary species migrated from their centers of origin to other parts of the world (Rehn, 1945). Over 40 nondomiciliary species have been carried by ship from the American Tropics to other parts of the world in cargoes of bananas (p. 146). In addition to these, other adventive cockroaches appear from time to time in ports to which they have been carried by ships. Yet by far the most numerous cockroaches on shipboard are the breeding populations of a few common domiciliary pests. Except in the most rigorously disinsectized ships, this commerce in cockroaches has continued to the present day.

Cockroaches undoubtedly infested the first ships that sailed the Mediterranean; of these we have no records. The earliest recognizable record of cockroaches on shipboard is Moffett's (1634) statement that when Drake captured the ship Philip, he found it overrun with cockroaches [Blattarum alatarum]. Bligh (1792) described disinfesting H.M.S. Bounty with boiling water to kill cockroaches. Chamisso (1829) reported that he had seen ships casks, in which rice or grain had been stored, that were found to be filled with Blattella germanica when opened. During a voyage from England to Van Diemen's Land, Lewis (1836) was greatly annoyed by hundreds of cockroaches flying about his cabin at night; the most numerous resembled Periplaneta americana and another was similar to Ectobius lapponicus. This latter was undoubtedly B. germanica, which is the only ship-infesting species that resembles the feral E. lapponicus. Lewis continued, P. americana "were in immense profusion, and had communication with every part of the ship, between the timbers or skin. The ravages they committed on everything edible were very extensive; not a biscuit but was more or less polluted by them, and amongst the cargo 300 cases of cheeses, which had holes in them to prevent their sweating, were considerably damaged, some of them being half devoured and not one without some marks of their residence."

Kingsley (1870), Kellogg (1908), Gates (1912), Heiser (1936), and Bronson (1943) have all reported that cockroaches were so numerous on ships that they gnawed the skin and nails of the men on board. These are all independent observations of what may well have been a common occurrence on ships. We have discussed in detail the subject of cockroaches biting man in our 1957(a) paper.

Mosely (1892) reported, "At the time that England was left the ship [H.M.S. Challenger] seemed nearly free of animals, other than men, dogs, and livestock required for food. The first cockroaches apparently came on board at St. Vincent, Cape Verdes.... Cockroaches soon became plentiful on board, and showed themselves whenever the ship was in a warm climate.

"At one period of the voyage, a number of these insects established themselves in my cabin, and devoured parts of my boots, nibbling off all the margins of leather projecting beyond the seams on the upper leathers."

Sir Edmund Freemantle (1904) recalled some of his experiences in the British Navy. "Cockroaches in the tropics were also terrible scourges. One saw little of them in fine, dry weather, but in damp, wet weather they seemed to come from every hidden corner ... our remedy in the 'Spartan' was to make the boys catch them—on pain of being caned.... One brig, the 'Lily,' was so overrun by cockroaches that the officers' clothes smelt of them."

The quotation from Sonan (1924) on page 348 describes similar conditions in the Japanese Navy.

On modern cargo ships cockroaches are reported to be extremely numerous in the galley, the crew's quarters, and sometimes in the holds; they dwell in hot, humid environments such as the casing around steam pipes (Monro, 1951). Williams (1931) reported that Blattella germanica was the most important cockroach pest on ships seen at New York. Although often numerous in the holds, the cockroaches as a rule congregated in living quarters. They were also frequently found between tarpaulins covering the hatches. It was not unusual to kill 20,000 to 50,000 in the forecastle, and more than 20,000 have been taken from a single stateroom. Simanton (1946) inspected the S.S. William Kieth when it berthed at San Francisco from a 10-month voyage to the South Pacific. The holds were infested with thousands of Periplaneta americana, but in the crew's quarters, mess halls, and storerooms B. germanica predominated. After insecticidal treatment about 2,000 P. americana were seen in each hold and as many as 24 B. germanica in each cabin. Richardson (1947) reported that in Army transports inspected between 1943 and 1946 at New York, P. americana was found in the galleys and messes, and occasionally heavy infestations were found deep in the holds; B. germanica was found in the galleys and messes; Blatta orientalis was found only in the hold.

Additional references indicating the presence of Blattella germanica on ships may be found in the account of its parasite Ripidius pectinicornis (p. 232). Although Rice (1925) and Williams (1931) cite B. germanica as the most numerous cockroach on ships, Brooke (1920) stated that the great majority of ship cockroaches were Periplaneta americana. In addition to citing cockroach infestations on ships, the following authors reported various methods for disinfecting ships: Canalis (1916), Pryor (1918), Brooke (1920), Rice (1925), Williams (1931), Simanton (1946), Richardson (1947), and Anonymous (1951, 1954).

COCKROACHES ASSOCIATED WITH SHIPS

In the following list we include some previously unpublished data on cockroaches that were recovered from ships at the Miami, Fla., Quarantine Station for the periods November 1945 through May 1946; May, June, August, and September 1950; and 17 July 1957 (Porter, personal communication, 1958). These data were lumped, without breakdown to species, under the entry Orthoptera in Porter (1958).

Certain of the species listed below occur only accidentally on shipboard and will probably never establish breeding colonies on ships or become pests on shipboard or elsewhere; some were merely passengers between one land-based colony and another. Others, the truly domiciliary pests, are as likely to be pests on shipboard as they are in land-based structures.

Blaberus discoidalis

Hispaniola.—On board ship (Rehn and Hebard, 1927).

Blatta orientalis

U.S.A.—At Port of New York (Richardson, 1947).

Blattella germanica

At sea?—In ships casks (Chamisso, 1829).

U.S.A.—Port of New York (Williams, 1931; Richardson, 1947). San Francisco (Simanton, 1946). At Miami, 7,852 live specimens recovered from ships (Porter, personal communication, 1958). Most numerous species on ships (Rice, 1925).

Epilampra maya

At sea.—One male and one female found dead on S.S. Tenadores (Hebard, 1917).

Epilampra sp.

Florida.—One dead specimen, Miami (Porter, personal communication, 1958).

Ischnoptera sp.

Florida.—Five live and one dead specimen, Miami (Porter, personal communication, 1958).

Latiblattella sp.

At sea.—One female alive in hold of S.S. Tenadores (Hebard, 1917).

Leucophaea maderae

Brought from West Africa to West Indies and Brazil by slave ships (Rehn, 1945).

Nauphoeta cinerea

Widely disseminated by sailing ships (Rehn, 1945).

Neoblattella fratercula

At sea.—Two females found dead on S.S. Tenadores (Hebard, 1917).

Neoblattella fraterna

At sea.—One male found dead in hold of S.S. Tenadores (Hebard, 1917).

Neoblattella nahua

At sea.—One female dead in hold of S.S. Tenadores (Hebard, 1917).

Neoblattella sp.

Florida.—Five dead specimens recovered from ships, Miami (Porter, personal communication, 1958).

Neostylopyga rhombifolia

Widely distributed by sailing ships (Rehn, 1945).

England.—Captured on a sugar vessel from Java (Lucas, 1920).

Nyctibora noctivaga

At sea.—One male and one female nymph found dead on S. S. Tenadores (Hebard, 1917).

Nyctibora sp.

Florida.—Two dead specimens recovered from ships at Miami (Porter, personal communication, 1958).

Oxyhaloa buprestoides

Spread from Africa to New World by ships (Rehn and Hebard, 1927; Rehn, 1945).

Panchlora nivea

At sea.—One female dead in hold of S.S. Tenadores (Hebard, 1917).

Florida.—Fifteen dead specimens taken from ships, Miami (Porter, personal communication, 1958).

From the numerous records of this species as an adventive taken on bananas (p. 150), it may be presumed to be a frequent traveler on banana boats.

Periplaneta americana

At sea.—Lewis (1836). Hebard (1933a) stated that this is "often a serious pest on the smaller ships sailing the South Seas."

U.S.A.—San Francisco (Simanton, 1946). Port of New York (Richardson, 1947). At Miami, 62 live and 123 dead specimens (Porter, personal communication, 1958).

Periplaneta australasiae

Migrated from West Africa to America in slave ships (Rehn, 1945).

Pycnoscelus surinamensis

Probably in part reached the New World by way of Africa in slave ships (Rehn, 1945).

Supella supellectilium

Reached America from West Africa by slave ship (Rehn, 1945).

Xestoblatta festae

At sea.—One female found dead in hold of S.S. Tenadores (Hebard, 1917).

AIRCRAFT

Michel (1935) stated that the development of air transportation brought the same insect dispersal problems that exist in land and water transportation; in addition, the problem of cockroach infestation had become a very serious one, quite aside from the hygienic point of view, because it had been discovered that these insects seek out the wings of airplanes, where they subsisted on the glue and dope used in airplane construction. However, Dethier (1945) found no cockroaches in dismantled or wrecked wing and tail structures of metal aircraft in central Africa. In fact, all-metal aircraft would seem to provide little in the way of food or water for stowaway cockroaches.

Laird (1951, 1952, 1956a) found living specimens of Blattella germanica, Periplaneta americana, and Periplaneta australasiae in baggage compartments and/or kitchens in aircraft. Other species which have been recovered from undisclosed spaces in aircraft are listed below. Some of the cockroaches that were reported as dead may not have died from exposure during flight but may have been killed by insecticide applied by inspecting personnel at the airports.

COCKROACHES ASSOCIATED WITH AIRCRAFT

In the following list we include some previously unpublished data on cockroaches that were recovered from aircraft in Miami, Fla., International Airport from 1 July 1956 through 30 June 1957 (Porter, personal communication, 1958). These data were lumped under the entry Orthoptera without breakdown to species in Porter (1958).

Species reported by Hughes (1949), and cited below as from southern United States, were recovered from aircraft that arrived at Brownsville, Fort Worth, Miami, New Orleans, and San Juan. There was no way of linking a specific record with any particular city.

The comments we made above about species that are infrequently encountered on ships apply with equal validity to similar species found on aircraft.

Anaplecta sp.

U.S.A.—One live and 15 dead specimens recovered from 16 aircraft at Miami (Denning et al., 1947).

Blatta orientalis

U.S.A.—Six live and four dead specimens recovered from six aircraft at Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

Blattella germanica

Hawaii.—Williams (1946a).

Khartoum.—Whitfield (1940).

New Zealand.—Laird (1951, 1952, 1956a).

U.S.A.—At Miami 193 live and 184 dead specimens were recovered from 141 aircraft (Denning et al., 1947). Recovered at airports in southern U.S. (Hughes, 1949). Recovered at Miami, 51 live and 24 dead specimens (Porter, personal communication, 1958). Exposed experimentally in jet aircraft (Sullivan et al., 1958).

Blattella sp.

Khartoum.—Whitfield (1940).

Southern U.S.—Hughes (1949).

Cariblatta ssp.

U.S.A.—One live and three dead specimens recovered from three aircraft at Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

Epilampra sp.

U.S.A.—One dead specimen, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

Eublaberus posticus

Southern U.S.—Hughes (1949).

Ischnoptera rufa rufa

U.S.A.—Two dead specimens recovered from two aircraft at Miami (Denning et al., 1947).

Ischnoptera sp.

U.S.A.—Two live and one dead specimen recovered from three aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949). One dead specimen, Miami (Porter, personal communication, 1958).

Leucophaea maderae

U.S.A.—Three dead specimens recovered from three aircraft at Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

Nauphoeta cinerea

U.S.A.—One live and one dead specimen, Miami (Denning et al., 1947).

Neoblattella sp.

U.S.A.—One dead specimen recovered at Miami (Denning et al., 1947).

Panchlora nivea

U.S.A.—Two dead specimens recovered from two aircraft, Miami (Denning et al., 1947).

Periplaneta americana

U.S.A.—Five live and three dead specimens recovered from seven aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949). Three live and five dead, Miami (Porter, personal communication, 1958). Experimentally exposed in jet aircraft, U.S. (Sullivan et al., 1958).

New Zealand.—Laird (1951, 1952).

Periplaneta australasiae

U.S.A.—Two dead specimens recovered from two aircraft, Miami (Welch, 1939). Five live and three dead from five aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949). Three live and two dead, Miami (Porter, personal communication, 1958).

New Zealand.—Laird (1952).

Periplaneta spp.

U.S.A.—One live and three dead specimens from four aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949). One live and six dead, Miami (Porter, personal communication, 1958).

Pycnoscelus surinamensis

U.S.A.—Two live and three dead specimens from five aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

New Zealand.—Laird (1956a).

Supella supellectilium

U.S.A.—Two live and one dead specimen from one aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

Khartoum.—Whitfield (1940).

Supella sp.

U.S.A.—Two live specimens from two aircraft, Miami (Welch, 1939). Southern U.S. (Hughes, 1949).

Symploce sp.

U.S.A.—Two live and one dead specimen from three aircraft, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949).

Unidentified cockroaches

Anglo-Egyptian Sudan.—At Khartoum (Whitfield, 1940).

Brazil.—From flying boats, 62 specimens; from land planes, 45 specimens (Carneiro de Mendonça and Cerqueira, 1947).

Central Africa.—Dethier (1945).

Kenya.—At Kisumu (Symes in Whitfield, 1940).

New Zealand.—Laird (1956a).

U.S.A.—Four live and 14 dead specimens from 4 aircraft, Miami (Welch, 1939). One live and 15 dead specimens (adults?) from 16 aircraft; 8 oöthecae from 7 planes; 147 live and 83 dead nymphs from 108 planes, Miami (Denning et al., 1947). Southern U.S. (Hughes, 1949). Five live and 7 dead specimens, Miami (Porter, personal communication, 1958).