Page:The naturalist on the River Amazons 1863 v1.djvu/80

two by two chattering to each other, the pairs being separated by regular intervals; their bright colours, however, were not apparent at that height. After breakfast we devoted the hours from 10 a.m. to 2 or 3 p.m. to entomology; the best time for insects in the forest being a little before the greatest heat of the day. We did not find them at all numerous, although of great variety as to species. The only kinds that appeared in great numbers of individuals were ants, termites, and certain species of social wasps; in the open grounds dragon-flies were also amongst the most abundant kinds of insects. Beetles were certainly much lower in the proportion of individuals to species than they are in England, and this led us to the conclusion that the ants and termites here must perform many of the functions in nature which in temperate climates are the office of Coleoptera. As to butterflies, I extract the following note from many similar ones in my journal. "On Tuesday, collected 46 specimens, of 39 species. On Wednesday, 37 specimens, of 33 species, 27 of which are different from those taken on the preceding day." The number of specimens would be increased if I had reckoned all the commonest species seen, but still the fact is well established, that there is a great paucity of individuals compared with species in both Lepidoptera and Coleoptera. We rarely saw caterpillars. After several years' observation, I came to the conclusion that the increase of these creatures was checked by the close persecution of insectivorous animals, which are excessively numerous in this country. The check operates at all periods of life—on the eggs, the larvæ, and the perfect insects.