84 RIO DE JANEIRO. [CHAP. n. 



and female, were chasing each other in an irregular course, 

 they passed within a few yards of me ; and I distinctly heard 

 a clicking noise, similar to that produced by a toothed 

 wheel passing under a spring catch. The noise was conti- 

 nued at short intervals, and could be distinguished at about 

 twenty yards' distance : I am certain there is no error in the 

 observation. 



I was disappointed in the general aspect of the Coleoptersu 

 The number of minute and obscurely-coloured beetles is exceed- 

 ingly great.* The cabinets of Europe can, as yet, boast only of 

 the larger species from tropical climates. It is sufficient to 

 disturb the composure of an entomologist's mind, to look fofVard 

 to the future dimensions of a complete catalogue. The carnivorous 

 beetles, or Carabidae, appear in extremely few numbers within the 

 tropics : this is the more remarkable when compared to the case 

 of the carnivorous quadrupeds, which are so abundant in hot 

 countries. I was struck with this observation both on entering 

 Brazil, and when I saw the many elegant and active forms of 

 the Harpalidae re-appearing on the temperate plains of La Plata. 

 Do the very numerous spiders and rapacious Hymenoptera sup- 

 ply the place of the carnivorous beetles ? The carrion-feeders 

 and Brachelytera are very uncommon ; on the other hand, the 

 Rhyncophora and Chrysomelidae, all of which depend on the 

 vegetable world for subsistence, are present in astonishing num- 

 bers. 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 different countries de- 

 pends. The orders Orthoptera and Hemiptera are particularly 

 numerous ; as likewise is the stinging division of the Hymeno- 

 ptera; the bees, perhaps, being excepted. 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, 



* I may mention, as a common instance of one day's (June 23rd) collect- 

 ing, when I was not attending particularly to the Coleoptera, that I caught 

 sixty-eight species of that order. Among these, there were only two of the 

 Carabidae, four Brachelytra, fifteen Rhyncophora, and fourteen of the Chry- 

 somelidse. Thirty-seven species of Arachnidse, which I brought home, wil/ 

 De sufficient to prove that I was not paying overmuch attention to the gene 

 rally favoured order of Coleoptera. 



