. Annual report of the New York State College of Agriculture at Cornell University and the Agricultural Experiment Station. New York State College of Agriculture; Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). Fig. 2.—Sprouts on a cabbage stump in spring the weather is favorable. By taking this cabbage aphis into the warm greenhouse during the winter we have bred as many as thirty generations in one year. In Fig. 3 is shown a mother aphis with a small brood of young ones on a cab- bage leaf. The mother aphis is just starting the colony, but it will increa
. Annual report of the New York State College of Agriculture at Cornell University and the Agricultural Experiment Station. New York State College of Agriculture; Cornell University. Agricultural Experiment Station; Agriculture -- New York (State). Fig. 2.—Sprouts on a cabbage stump in spring the weather is favorable. By taking this cabbage aphis into the warm greenhouse during the winter we have bred as many as thirty generations in one year. In Fig. 3 is shown a mother aphis with a small brood of young ones on a cab- bage leaf. The mother aphis is just starting the colony, but it will increase until perhaps the whole leaf is covered with aphids so closely packed together that one could not put a finger on the leaf without touch- ing several of them. Finally, late in the autumn, the true shining black eggs (Fig. i) are again laid on the leaves, thus completing a very in- teresting life history. One interesting phase of the life of these aphids, and also of other species of plant lice, is the sudden appearance of individuals with wings. The first gen- eration of lice hatched from the eggs on the cabbage sprouts in the spring are all without wings. Indeed, the individuals of the second generation are wingless, so far as has been observed; but in the third and following generations there appear many individuals that possess wings. This is really a very remark- able thing, and scientists have been wondering and guessing for many years as to why these winged lice appear and what causes them to appear. Certain it is, that these winged aphids fly away to other cabbages or other food plants and there start new colonies. Per-. FiG. 3.—Mother aphis with colony of young aphids. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York State College of Agriculture; Cornell University. Agricultural Experi
Size: 1617px × 1545px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookidannualreportne19122newybookyear19111971albany
