Regular Meeting, March 7th, 1864.

President in the Chair.

Present twelve members; also Messrs. Turnbull, Smith, Gardiner, and Burgner, by invitation.

Donation to the Cabinet: Stuffed skin of a large venomous Snake, from the Sierra Madre of Mexico, east of Mazatlan, presented by Mr. Burgner.

Donations to the Library: Pamphlets on the North American Helicidæ, by Thomas Bland, extracted from the Annals of the N. Y. Lyceum of Natural History. American Journal of Science and Arts for January, 1864. Boston Journal of Natural History, Vol. VII, No. 4.

Dr. Behr presented the following paper:

On Californian Lepidoptera. No. IV.

BY H. BEHR, M.D.

Fam. Vanessidæ.

Grapta.

Grapta Comma Harris.

I possess but one specimen of this Grapta. It was collected by Dr. Hillebrand, in Yosemite Valley, during his late visit to California. It agrees in all essential points with two other specimens which I obtained through the kindness of Mr. W. H. Edwards, of New York. The California specimen differs by a somewhat lighter coloration on both sides, especially below where the ground color passes into a yellowish brown, while in the Eastern specimen it becomes a bluish gray. On the upper side, also, the bluish coloration of the edge of the angulated wings of the Eastern form is replaced by a yellowish tint.

I would be inclined to take G. Comma for a local variety of G. C-album, were it not for the caterpillar, which, according to Mr. Harris, resembles that of G. interrogationis, and is entirely without that strangely dimidiate coloration so characteristic in G. C-album.

In G. C-album I cannot find any difference between my Californian and European specimens. Our vernal generation is larger and somewhat lighter colored than any European specimens I have ever seen. The caterpillar has a curious dimidiate coloration, which I have never seen except in this species: the fore part being white, the abdominal part yellow. I found it on Urtica, but it will probably be found on other Urticaceous plants, herbaceous as well as arborescent. G. C-album is not common in the immediate neighborhood of San Francisco, but it is rather abundant in woody and mountainous districts.

The Atlantic States are richer in species of this genus than either Europe or California, the two latter of which possess the same number of species.

Europe. California. Atlantic Slope.

G. C-album. G. C-album. G. C-album.

G. Triangulum. G. Comma. G. Comma.

—— —— G. Faunus.

—— —— G. Progne.

—— —— G. interrogationis.

Vanessa Fabr.

Vanessa Californica Boisd.

The caterpillar of this species feeds on Ceanothus, and lives socially like that of V. Urticæ L., from which it differs very little. It is of a velvety black, and the spines which cover it are also black.

V. Californica is remarkable from its being one of the few wandering Lepidoptera yet known. The first migration I observed was on November 15th, 1856, when numbers of this butterfly flew over San Francisco in a general direction of south-south-east. They flew singly, and never crowded into swarms. Most of these butterflies passed over our streets at too great a height to permit close inspection—a few alighting here and there on lamp-posts, sign-boards, or in the more rural parts, on flowers. It was from these that I obtained the specimens in my collection. They nearly all looked worn and shattered, and there were no fresh specimens among them: clearly indicating that they were not raised in the neighborhood of the city, but had come from distant parts. On the 18th some of the stragglers were still to be seen, but on the 19th they had all disappeared. The second migration took place last fall, but did not reach San Francisco. I received a series of specimens, caught by Dr. Cooper, on the road to Lake Taho. Others I received from Oregon, where they were collected by Mr. Gabb, during his geological examination of those northern regions. Neither Dr. Cooper nor Mr. Gabb observed any marked direction in the flight of these butterflies; they agree that the species was strikingly numerous. Mr. Gabb represents it as settling on the ground in dry arroyos, very shy, and when frightened, always returning to the same spot—a behavior which pretty nearly corresponds with that of the nearest relative, the European V. Polychloros. Both of these authorities prove merely an unusual number of this butterfly at an unusual time of the year. The description of the habits of the insect, as observed by Mr. Gabb in the Umpqua Valley, show clearly that there it felt at home. By comparing notes received from Mr. Johnson, of Marin County, I have come to the conclusion that the country to the northward, crowded with this Vanessa, must have sent at least one colony south; and I was told by the above-mentioned gentleman, the statement being confirmed by several intelligent farmers of the same neighborhood, that large numbers of a brown butterfly had come from San Quentin, and crossed over that part of the bay which stretches between San Rafael and Saucelito. About the same time, great numbers of the same insect were observed in Lagunita Valley, at the base of Tamal Pais, where the swarms gathered in a great crowd, and disappeared as suddenly as they came.

I trust that my loquacity in regard to the habits of this species will be pardoned. I consider the observation of facts touching the migration of animals, of the highest importance, and think it desirable that all observations on these points should be put on record: so that hereafter, when a sufficient number of instances may have been collected, conclusions may be drawn, and perhaps many hitherto inexplicable points in the geographical distribution of insects, and of organic life in general, may be explained.

This butterfly is rather rare in common years, and is, perhaps, notwithstanding its name, V. Californica, not exactly an indigenous species, at least not in the middle counties of our State. Unlike all other Vanessidæ known to me, it has but one generation, at least in California, where the imago is always found late in the season. I do not venture to decide whether V. Californica requires a longer time for development in the larva state than the other Vanessidæ, or whether it has its vernal generations somewhere else in adjacent countries. I have found but one colony of caterpillars. It was in July, and most of the individuals were nearly full grown; they were rather delicate, the majority died in the larva state, seven transformed about the end of the month, and a single chrysalis produced a crippled butterfly.

Vanessa Milberti Godt.

This species is common in woody localities. The caterpillar is very much like that of V. Californica, and only a few individuals show a distinguishing mark in the shape of a longitudinal, lateral stripe of sulphur yellow. It feeds on Urtica.

Vanessa Antiopa L.

There is nothing to add in regard to this long and well-known species. The caterpillar feeds here, as everywhere else, on willows.

The true Vanessæ have about the same geographical distribution as the Graptæ. They also have a predilection for Urticaceous plants. Only the most northern species is amphigeic.

Europe. California. Atlantic Slope.

V. Antiopa. V. Antiopa. V. Antiopa.

V. Urticæ. V. Milberti. V. Milberti.

V. Polychloros. V. Californica. V. C-album.

There is a balance in favor of the Old World—the beautiful type of V. Io not being represented on this continent—and also the type of V. Polychloros, containing a few species, as, for instance, V. Xanthomelas, that make it appear more numerous.

Pyrameis Hubn.

Pyrameis Atalanta L.

Larva feeds on Urtica.

Pyrameis Carye.

This species is by far the most common butterfly in California. The caterpillar is very variable in its coloration, and is so like that of P. Atalanta, in company with which it is frequently found, that I have never succeeded in finding any distinguishing characters. It feeds throughout the year on Urtica and on several malvaceous plants, and has the habit of all its congeners, of hiding itself in a rolled up leaf.

Pyrameis Cardui L.

This most cosmopolitan of all diurnals, affects here, in its larva state, several malvaceous plants, and also the genus Gnaphalium, and its relations; but the plant for which it shows the greatest predilection is Silybum Marianum, a plant which formerly did not exist here, and has only spread since 1852. It now forms thickets in the neighborhood of San Francisco, as well as near most of our inland towns, but has never spread to a great distance from settlements. P. Cardui frequents the same localities, and I found the same species in Australia in the same relation to the same immigrated plant, Silybum Marianum. I know very well that P. Cardui existed here, as well as in Australia, before the immigration of this Mediterranean plant; but still, it is a remarkable fact that this cosmopolitan butterfly, notwithstanding its ability to adapt itself to plants of the most different families, still clings with such tenacity to a cosmopolitan plant, to whose universal distribution it is perhaps much indebted for the wide range which it itself attains.

Next to the cosmopolitan character of this plant, P. Cardui owes its great extent probably to its many generations and certain irregularities in the time of the appearance of the perfect insect; so that small colonies of the species are not so liable to be destroyed by inclemency of climate or exceptional atmospheric agencies; for a being that exists at the same time in the four stages of the egg, larva, chrysalis, and imago, has more chances of escaping cataclysms and deluge than others that are all at one time in the same stage of existence. The extent of the influence exerted by the number of generations, and the irregularity of period, can be very clearly recognized by the circumstance that species with one generation are always the most local; for instance, certain Meliteæ, Argynnidæ, Theclæ, most of Sphingidæ, etc.; that also the cosmopolitanism develops in proportion to the number of generations, and attains its maximum in certain Vanessidæ, Danaidæ, Pyrameis, etc.

Pyrameis Hunteri Fab.

This species seems to have, in California, but one generation. It is not common. I have found it only in the latter part of the season, and have not yet succeeded in finding the caterpillar. The genus Pyrameis has the widest range of all the genera of this family. It extends through all latitudes from the Arctic regions to the Cape of Good Hope and Cape Horn. On the northern hemispheres it is best represented in California, which country possesses one peculiar species in addition to all three of Europe and the Eastern Slope of the United States.

California. Eastern Slope. Europe.

P. Atalanta. P. Atalanta. P. Atalanta.

P. Carye. —— ——

P. Cardui. P. Cardui. P. Cardui.

P. Hunteri. P. Hunteri. ——

Junonia Hubn.

Junonia Cænia Boisd. et Lee.

Several generations. Caterpillar not yet found in California. From this enumeration of California Vanessidæ we find, 1st. That with the exception of V. Californica, there is not yet found any species of this group peculiar to our State, for even P. Carye exists as well in Chili as here, and is also said to have been found in Brazil. This circumstance is more striking since our Argynnidæ and Meliteæ prove altogether local; none of them being identical with Eastern species, unless a Melitæa, of the type of Mylitta, should be found identical with a form found in Texas. 2. The genera of this group, north of the Tropic of Cancer, are essentially amphigeic, the European Arachnia being almost the sole exception. But, as it were, to compensate this, the tropical amphigeic genus Junonia, wanting in Europe, extends, on our continent, to high latitudes. 3. As regards the number of specks, the genus Grapta predominates at the Eastern Slope, Vanessa in Europe, Pyrameis in California, and our own Junonia is counterbalanced in Europe by our Arachnia.

Fam. Limenitidæ.

Limenitis Fabr.

Limenitis Lorquini Boisd.

Like its congeners in other parts of the world, this species occurs in shady woods, or on the banks of arroyos. It is peculiar to California and Oregon.

Limenitis Eulalia Doubleday.

In localities similar to the preceding species. These two species are, as yet, the only ones found in our State. They represent a peculiar type, forming, in their coloration, a transition from Limenitis to the South American genus Heterochroa. Neither of these Californians have been found on the Eastern Slope. L. Eulalia extends to Mexico.

The family Apaturidæ as yet, has not been found in California.

Dr. Trask offered the following article:

Earthquakes in California During the Year 1863.

BY JOHN B. TRASK, M.D.

During the year 1863 we have had but five earthquakes, and as in former years they have been marked by no serious event, if we except the light degree of fright induced at the time among our people.

January 25th.—A severe shock was experienced at San Diego at 2h. 20m. M., which lasted five to eight seconds. There was no undulation in this case, it consisting of a series of sharp jars. It was preceded by a deep rumbling noise.

February 1st.—A very smart shock at the Mission San Juan, Monterey County, at 4h. 1m. P.M. This shock was felt at Gilroys at 4h. 15m. This town is twelve miles east of the former. At both places the shock was marked by the undulatory motion. It was not observed at Monterey, which is nearly twelve miles west of the Mission.

June——A smart shock at midnight at San Francisco.

August 1st.—Two light shocks at San Francisco, at 10h. 48m. P.M., and at 11h. 6m. P.M., another shock.

December 19th.—At 2h. 38m. P.M. a smart shock was felt throughout the city; directly afterwards another and more severe one occurred. The first was a short, sudden jar, while the second was undulatory. The accuracy of the telegraph operator at Santa Clara has enabled us to form a correct idea of the course of this shock, and to correct to some extent the popular errors relating to the direction of the seismic wave. His time was 2h. 44m. 31s., being within 29 seconds of true time, which would then be 2.45. This gives us only 6½ minutes difference in elapsed time, and gives for the direction of the wave an east course in place of north and south, as reported, which corresponds to our measured observations here. I take this opportunity of expressing the thanks of the Academy to this operator for his accuracy and kindness in furnishing us data in this and other phenomena of scientific and public interest.

February and March, 1864.

During the present year, 1864, we have had two smart earthquakes at the date of writing this report.

February 26th.—At San Francisco a light shock at 0h. 40m. M., and another at 2h. 10m. M. These were reported to me by persons who were up in the south and west parts of the city. At 5h. 47m. a very smart shock occurred, having three distinct vibrations, which induced many to rise somewhat earlier than was usual. This earthquake was preceded by a strong electric storm (so called here), between this city and Visalia; the particulars of which have not as yet all come to hand. It was followed next day by one of those severe “northers” with which the people of this State are very familiar. Barometer very low. This fact is mentioned only on account of the unseasonable period at which the gale occurred.

This earthquake was felt more severe at San José and Santa Clara than at this place, and occurred at nearly the same hour.

March 5th.—A severe shock of earthquake at San Francisco at 8h. 49m. M. The first wave had a north and south direction and continued 1¾ seconds; nearly 1¾ seconds elapsed before the second shock, which was at 8h. 49m. 3s., and continued 1½ seconds. The second shock was rotatory; the pendulum swinging north and south from the first shock, began and continued to describe a short oval or nearly a circle from the effects of the second shock, and continued thus for more than half an hour, until stopped and brought to rest. Magnetism was not suspended in this earthquake, nor any other that has occurred since my instrument was suspended. These observations were made at the height of twenty feet four inches from the ground. The total of time included in the shock was nearly five seconds. The farthest point south to which I have been able to trace its effects is the Mission San Juan, and north to Sacramento, a distance inclusive of 177 miles. In an easterly direction we have not traced it east of Stockton, about 60 miles. It was felt at Santa Clara, Santa Cruz, Gilroys, south of San Francisco, and at Santa Rosa and Petaluma to the north.

Since the above was in type, advices have been received from Visalia. At that locality the shock was very smart. The first shock took place at 8h. 45m. M., being four minutes earlier than that at San Francisco. This gives for the entire distance, north and south (over which the earthquake extended), 257 miles. This extent of latitude, and the almost simultaneous period of time at which it was observed along the entire line of distance so far as heard from, leads to the conclusion that its probable centre was south of San Francisco and nearly in the same longitude. From the violence of its action I feel inclined to the belief that its centre was in the neighborhood of San José, for all accounts agree in this one point, that more turbulence of the earth’s surface occurred in this region during its continuance than at any other place yet known. At Visalia the first shock was a mere tremor, but was followed by an undulatory movement when the second shock occurred, which was some three or four seconds later. This wave moved in an east and west direction at that place.