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. ontiguensis 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*,) arid 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 Scarabaidte. Ontlwpliagus 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. 



