27 G FOREST ENTOMOLOGY. 



Genu)i ScHizoNEUUA. 



As regards the structural details, the following geiieric characters 

 are given by Buckton — viz. : 



" Eostrum moderately long in the adult, much longer in the young. 



" AntennjB with six articulations, omitting the terminal unciform 

 process. 



" The first and second joints very short, the third much the longest, 

 and in all cases either ringed or cupped ; the fourth and fifth about 

 equal, and also usually ringed ; the sixth joint rather shorter than the 

 preceding, and ending with a rudimentary joint, a small tubercle 

 sometimes separating the two parts. 



" Cornicles rudimentary or none ; legs short. Tarsi furnished with 

 two claws. Body either powdered with a mealy substance or fur- 

 nished with wool-like tufts. 



" Wings modei-ately long, cubital, witli a single furcation, and in 



Fig. 200. — Leaves of wycli elm rolled hi/ Scliizoneura ulmi. 



most species springing at some considerable distance clear from the 

 cubitus. 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 we 

 find a reaction of the vegetable organism against the insect attack. 

 In other words, we get gall structure and its modification. The 

 various figures given by Eeaumur and others would seem to suggest 

 that those features have been recognised for a very long time. 



The arboreal species chiefly confine their attacks to the foliage. 

 The curling of the leaves of elm (fig. 260) is a very conspicuous 

 feature throughout the country. If the curl arises from the gnawing 

 of one stem-mother, then a single straight roll of half the leaf is 

 the result, but if the same leaf is seized by more than one stem- 

 mother, then the deformed leaf assumes various distorted shapes. 



