Page:Popular Science Monthly Volume 8.djvu/303

Rh was disposed to regard as a separate genus, Akephorus. This form is, therefore, in a condition of evolution—how, I know not—our descendants may. The Atlantic species are winged; the Pacific ones, like a large number of insects of that region, are without wings.

Accompanying these are Coleoptera of other families, which have been less carefully studied, but I will not trespass upon your patience by mentioning more than two. Bledius pallipennis (Staphylinidæ) is found on salt marshes near New York, on the Southern sea-coast, and in Kansas; Ammodonus fossor, a wingless Tenebrionide, Trenton seashore near New York, and valley of the Mississippi at St. Louis; thus nearly approximating Cicindela lepida in distribution.

We can thus obtain by a careful observation of the localities of insects, especially such as affect sea-shore or marsh, and those which, being deprived of their favorite surroundings, have shown, if I may so express myself, a patriotic clinging to their native soil, most valuable indications in regard to the time at which their unmodified ancestors first appeared upon the earth. For it is obvious that no tendency to change in different directions by "numerous successive slight modifications" would produce a uniform result in such distant localities, and under such varied conditions of life. Properly studied, these indications are quite as certain as though we found the well-preserved remains of these ancestors in the mud and sand strata upon which they flitted or dug in quest of food.

Other illustrations of survivals from indefinitely more remote times I will also give you, from the Coleopterous fauna of our own country, though passing time admonishes me to restrict their number.

To make my remarks intelligible, I must begin by saying that there are three great divisions of Coleoptera, which I will name in the order of their complication of structural plan: 1. Rhynchophora; 2. Heteromera; 3. Ordinary or normal Coleoptera; the last two being more nearly allied to each other than either is to the first. I have in other places exposed the characters of these divisions, and will not detain you by repeating them.

From paleontological evidence derived from other branches of zoölogy, we have a right to suppose, if this classification be correct, that these great types have been introduced upon the earth in the order in which I have named them.

Now, it is precisely in the first and second series that the most anomalous instances of geographical distribution occur; that is to say, the same or nearly identical genera are represented by species in very widely-separated regions, without occurring in intermediate or contiguous regions. Thus there is a genus Emeax, founded by Mr. Pascoe, upon an Australian species, which, when I saw it, I recognized as belonging to Nyctoporis, a California genus, established many years before; and, in fact, barely specifically distinct from N. galeata.