Guide to the study of insects, and a treatise on those injurious and beneficial to crops: for the use of colleges, farm-schools, and agriculturists . ising from the main subcostal vein and directed out-wards, and there are no honey tubes ; otherwise these insectsclosely resemble the Aphides. A species (Fig. 520; o, pupaseen from beneath) closely related to the European Adelges(Chermes) cocci neus of Ratzburg, and the A. strobilobiun ofKaltenbach, which have similar habits, we have found in abun-dance on the spruce in Maine, where it produces swellings atthe end of the twigs,resembling in sizea
Guide to the study of insects, and a treatise on those injurious and beneficial to crops: for the use of colleges, farm-schools, and agriculturists . ising from the main subcostal vein and directed out-wards, and there are no honey tubes ; otherwise these insectsclosely resemble the Aphides. A species (Fig. 520; o, pupaseen from beneath) closely related to the European Adelges(Chermes) cocci neus of Ratzburg, and the A. strobilobiun ofKaltenbach, which have similar habits, we have found in abun-dance on the spruce in Maine, where it produces swellings atthe end of the twigs,resembling in sizeand form the conesof the same tree. The most destruc-tive insect of thisfamily is the GrapePhylloxera, P. vlti- FS- ™>. JoI/«J Fitch (P. vtestatrix Planchon). It exists in two forms,one raising irregular galls on the leaves, and the other form-ing small swellings on the rootlets. The root-form is bothwingless and winged, the latter very rare. The leaf-form issaid to be always wingless. Fig. 521 (after Riley) representsthe wingless leaf- O form ; a, b, newlyhatched 1 a r v a,ventral and dor-sal view; c, egg;<7, section of leaf-. gall •^j e, swelling of tendril ;/,</,/<,mother gall-louselateral, dorsal,and ventralviews ; £, anten-na;^, two-jointedtarsus. Fig. 521 a,
Size: 2411px × 1036px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookpublishe, booksubjectinsects
