Economic entomology for the farmer and fruit-grower : and for use as a text-book in agricultural schools and colleges . Cocks-comb gall on elm, Colopha ulmicola.—a, elm-leaf showing galls; b, winteregg, covered by the skin of the true female ; c, larva just hatched ; d, pupa ; e, wingedadult. the progeny of the single specimen which caused the growth ofthe gall early in the season. There are many other gall-producinglice, perhaps the best-known being the Colopha ulmicola, found onelm, and forming the cocks-comb gall. The popular namefairly describes the appearance of the abnormal growth, which
Economic entomology for the farmer and fruit-grower : and for use as a text-book in agricultural schools and colleges . Cocks-comb gall on elm, Colopha ulmicola.—a, elm-leaf showing galls; b, winteregg, covered by the skin of the true female ; c, larva just hatched ; d, pupa ; e, wingedadult. the progeny of the single specimen which caused the growth ofthe gall early in the season. There are many other gall-producinglice, perhaps the best-known being the Colopha ulmicola, found onelm, and forming the cocks-comb gall. The popular namefairly describes the appearance of the abnormal growth, whichis an inch or more in length and about one-quarter of that inheight. None of these gall-making species are abundant enoughto be seriously troublesome ; but quite the contrary is true of the THE INSECT WORLD. 133. Woolly apple-louse, Schizoneura lanigcra: showing a group of specimens on bark, a crevice on abraiicli, in which they congregate, and a wingedform. woolly plant-lice, belonging to the ^^nw^ Schizoneura. These cover themselves with a secretion resembling fine cottony fibre, which conceals them more or less completely. Thus there may appear to be tuits of cot- „ Fig. attached to leaves or twigs, beneath eachof which we find, how-ever, a great mass ofplant lice busily en-gaged in feeding. The alder ? blight andbeech-blight are dueto species of this kind,and more importantthan all is the apple-blight, or the woollyapple-louse. This spe-cies, Schizoneura lani-gera, has been intro-duced into other countries, and is known in England and Aus-tralia as the American blight. Young trees are frequentlyinjured by these aphids, which gather in masses on the trunks,and cause the death of the bark below the point of attack. Theeggs may be found singly in the bark ^^^- 98- crevices during w
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectinsectp, bookyear1906
