GEOGRAPHICAL DISTRIBUTION OF INSECTS. 489 
Aphides of every climate from pole to pole. The Li- 
bellulina pursue their prey both in Greenland and New 
Holland. The saprophagous carnivora are also similarly 
predominant ;—the Silphide, the Dermestide, the Bra- 
chelytra, the Muscide, prey on carcases wherever the 
action of the solar beam causes them to become putrid. 
Many of the above insects have probably their capztal 
station, or that where the species are most numerous, in 
or near the tropics; but the metropolis of the Brachely- 
tra (Staphylinus L.), at least as far as we can judge from 
our present catalogues, is within the temperate zone, par- 
ticularly in Britain?. The coprophagous Petalocera are 
most abundant in the hottest climates; but the dphodiade 
form a predominant group: Professor Hooker teok one 
species in Iceland, and it probably ascends higher; 
others are found in India and China: but the metropolis 
of the group is within the temperate zone. Perhaps no 
genus is more completely universal than Bombus (Bre- 
mus Jur.), which, although its centre or metropolis is 
likewise in the northern temperate zone, extends from 
Melville Island to the line. It is remarkable that some 
of the tropical Bomb: wear the external aspect of Xylo- 
cope, the kindred genus most prevalent in warm cli- 
mates; and, vice versd, some Xylocope resemble Bombi. 
I have a Brazilian undescribed species of the latter ge- 
nus, whose black body and violet-coloured wings would 
almost cause it to be mistaken for a variety of X. vzolacea ; 
and B.antiguensis and caffrus ¥., (though their aspect 
belies it,) which misled Fabricius, are true Xylocope. I 
4 De Jean in his catalogue gives only 434 species; while Mr. Ste- 
phens, four years ago, had 550, and has since increased the number to 
above 600. > Journal of a Tour in Iceland, 272. 
