490 GEOGRAPHICAL DISTRIBUTION OF INSECTS. 
shall mention only one other predominant group, but 
that one of no common celebrity, formed of the gnats, or 
genus Culex L. These piping pests, with their quiver— 
“venenatis gravida sagittis”—annoy man almost from 
the pole to the line. What remarkably distinguishes 
them, (as was formerly observed?,) and also the Simulium 
or true mosquito,—they appear to prevail mast in the 
coldest and the hottest climates, and the Laplander and 
the tropical American are equally their prey; while the 
inhabitants of the temperate zone, with some exceptions, 
suffer but little from them: so that they may be stated_to 
have both an arctic and a tropical metropolis. 
2. There are other groups which, though their empire 
extends to the tropics, fall short of the polar circles :— 
these I call dominant groups. Of this description are 
some of the Scarabaide M*L. Onthophagus is found 
both in the old world and in the new, and in the tempe- 
rate and torrid zones. Its principal seat appears to be 
within the tropics, but it may almost be said to have also 
a northern metropolis. More than one species have 
been taken in New Holland. In general, tropical insects 
exceed those of colder climates in szze; but in the genus 
we are speaking of, the European species are usually 
larger than the Indian. Copris seems more abhorrent 
of cold than its near relation Onthophagus. C. lunaris, 
which ranges northward as far as Sweden, is the only 
recorded species found in Europe out of Spain. La- 
treille says, that all the large species of this genus are 
equinoctial: but C. Tmolus, described and figured by 
Fischer °, found in Asia near Orenburg, northof 50° N.L., 
* Vou. I. p. 115—. " Entomogr. Russ. Coleopt. t. xiii. f. 1. 
