Forest entomology . require description. The species belonging to this tribe differ in two ways from insectsbelonging to the previous tribe, both as regards the structure of theinsects and the nature of the injuries. APHIDID^E. 315 Genus Schizoneura. As regards the structural details, the following generic charactersare given by Buckton—viz. : Rostrum moderately long in the adult, much longer in the young. Antennae with six articulations, omitting the terminal unciformprocess. The first and second joints very short, the third much the longest,and in all cases either ringed or cupped ; the four
Forest entomology . require description. The species belonging to this tribe differ in two ways from insectsbelonging to the previous tribe, both as regards the structure of theinsects and the nature of the injuries. APHIDID^E. 315 Genus Schizoneura. As regards the structural details, the following generic charactersare given by Buckton—viz. : Rostrum moderately long in the adult, much longer in the young. Antennae with six articulations, omitting the terminal unciformprocess. The first and second joints very short, the third much the longest,and in all cases either ringed or cupped ; the fourth and fifth aboutequal, and also usually ringed ; the sixth joint rather shorter than thepreceding, and ending with a rudimentary joint, a small tuberclesometimes separating the two parts. Cornicles rudimentary or none; legs short. Tarsi furnished withtwo claws. Body either powdered with a mealy substance or fur-nished with wool-like tufts. Wings moderately long, cubital, with a single furcation, and in ,,>--. Fig. 289.—Leaves ofwych elm. rolled by Schizoneura ulmi. most species springing at some considerable distance clear from thecubitus. The post-costal nervures of the hind wings nearly straight,and giving rise to the usual two oblique veins. With regard to the damage, it may be noted that in this tribe wefind a reaction of the vegetable organism against the insect other words, we get gall structure and its modification. Thevarious figures given by Reaumur and others would seem to suggestthat those features have been recognised for a very long time. The arboreal species chiefly confine their attacks to the curling of the leaves of elm (fig. 289) is a very conspicuousfeature throughout the country. If the curl arises from the gnawingof one stem-mother, then a single straight roll of half the leaf isthe result, but if the same leaf is seized by more than one stem-mother, then the deformed leaf assumes various distorted shapes. 316 FOREST ENTOMOLOG
Size: 2429px × 1029px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisheredinburghwblackwoo
