GEOGRAPHICAL DISTRIBUTION OF INSECTS. 501 



Leay has an undescribed species from New Holland ; 

 and C. retusum was taken in Terra del Fuego. Another 

 genus, equally universal and richer in numbers, is the 

 lady-bird (Coccinella), which keeps within due limits the 

 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 Silphidoe, the Dermestidce, the Bra- 

 diyptera, the Muscidte, prey on carcases wherever the 

 action of the solar beam causes them to become putrid. 

 Many of the above insects have probably their capital 

 station, or that where the species are most numerous, in 

 or near the tropics ; but the metropolis of the Brachy- 

 ptera, at least as far as we can judge from our present 

 catalogues, is within the temperate zone, particularly in 

 Britain a . The coprophagous Petalocera are most abun- 

 dant in the hottest climates ; but the Aphodiadce form a 

 predominant group: Professor Hooker took one species 

 in Iceland b , 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 (Bremus 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 Bombi wear the external aspect of Xylocopte, 

 the kindred genus most prevalent in warm climates; and, 

 vice versa, some Xylocopte resemble Bombi. I have a 

 Brazilian undescribed species of the latter genus, whose 



a Dejean 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. b Journal of a Tour in Iceland, 272. 



