Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomol00smit Year: 1906 THE nVSECT WORLD. 377 out devouring any part of its vegetable envelope, changes to a pupa, and emerges from the gall, leaving it intact, except for the hole through which it emerged. It seems, therefore, as if certain abnormal plant ex- udations secreted in the Fig. 433. gall form the actual food of the larva, and it is a curious and interesting fact that the same species in- variably produces in the same
Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomol00smit Year: 1906 THE nVSECT WORLD. 377 out devouring any part of its vegetable envelope, changes to a pupa, and emerges from the gall, leaving it intact, except for the hole through which it emerged. It seems, therefore, as if certain abnormal plant ex- udations secreted in the Fig. 433. gall form the actual food of the larva, and it is a curious and interesting fact that the same species in- variably produces in the same place the same kind of gall. In other words, the appearance of the gall is an unfailing index for the special student to the species that made it. Many interesting problems are connected with the study of these gall-flies ; for instance, in some species both sexes are present early in the season, but in the second or midsummer brood females alone make their appearance. The Fig. 434. An oak gall-fly.
Size: 1820px × 1099px
Photo credit: © Bookworm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
