502 GEOGRAPHICAL DISTRIBUTION OF INSECTS. 
black body and violet-coloured wings would almost 
cause it to be mistaken for a variety of X. violacea ; and 
B. antignensis and caffrus F., (though their aspect belies 
it,) which misled Fabricius, are true Xylocopce. I shall 
mention only one other predominant group, but that one 
of no common celebrity, formed of the gnats, or genus 
Culex. These piping pests, with their quiver — " vene- 
natis gravida sagittis " — annoy man almost from the pole 
to the line. What remarkably distinguishes them, (as 
was formerly observed 3 ,) and also the Simulium or true 
mosquito, — they appear to prevail most in the coldest 
and the hottest climates, and the Laplander and the tro- 
pical American are equally their prey; while the inha- 
bitants of the temperate zone, with some exceptions, suf- 
fer 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 Scarabceidcc. Onthophagus is found both 
in the old world and in the new, and in the temperate 
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 size ; 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 
a Vol. I. p. 115—. 
