May — June, 1832. entomology. 39 



only of the larger species from tropical climates. It is suf- 

 ficient to disturb the composure of an entomologist's mind, 

 to look forward to the future dimensions of a complete cata- 

 logue. The Carabidse appear in extremely few numbers 

 within the tropics. This is the more remarkable when com- 

 pared to the opposed case of the carnivorous mammalia, an 

 order which they certainly represent among insects. I was 

 struck with this observation both on entering Brazil, and 

 when I saw the elegant and active forms of the Harpalidce re- 

 appearing on the temperate plains of La Plata. Do the very 

 numerous Arachnidse and rapacious Hymenoptera supply the 

 place of these carnivorous beetles ? The carrion- feeders and 

 Brachelytra are very uncommon; on the other hand, the 

 Rhyncophora and Chrysomelidee, all of which depend on 

 the vegetable world for subsistence, are present in astonish- 

 ing numbers. I do not here refer to the number of different 

 species, but to that of the individual insects ; for on this it 

 is that the most striking character in the entomology of dif- 

 ferent countries depends. The orders Orthoptera and He- 

 miptera are particularly numerous ; as likewise is the stinging 

 division of the Hymenoptera ; the bees, perhaps, being ex- 

 cepted. A person, on first entering a tropical forest, is 

 astonished at the labours of the ants: well -beaten paths 

 branch off in every direction, on which an army of never- 

 failing foragers may be seen, some going forth, and others 

 returning, burdened with pieces of green leaf, often larger 

 than their own bodies. 



A small dark- coloured species sometimes migrates in 

 countless numbers. One day, at Bahia, my attention was 

 drawn by observing many spiders, cockroaches, and other 

 insects, and some lizards, rushing in the greatest agitation 

 across a bare piece of ground. A little way behind, every 

 stalk and leaf was blackened by a small ant. The swarm 

 having crossed the bare space, divided itself, and descended 

 an old wall. By this means many insects were fairly en- 

 closed ; and the efforts, which the poor little creatures made 

 to extricate themselves from such a death, were wonderful. 



