Note 37 — Chapter III · CAUSES OF VARIATION.

This is certainly rendered probable, however, from the fact that a large proportion of these apterous species are members of genera which are usually winged,—such as Tarus, Loricera, Calathus, Olisthopus, Argutor, Trechus, Hydrobius, Ephistemus, Syncalypta, Phlœophagus, Tychius, Longitarsus, Chrysomela, Scymnus, Corylophus, Helops, and Othius,—whilst the knowledge that, out of twenty-nine genera which I believe to be endemic in those islands, six only are winged (the remaining twenty-three being apterous), will not tend to diminish the probability that there is something peculiar in the action of Madeiran influences generally on the alary system of the insect tribes.