ORDER HTMEXOPT, 





sihly a »1 i irl 1 1 amount oi 



an abnormal growth <>f the plant-cells, until a i rned 



within which the larva hatches .- 1 1 1 < 1 lives Each B] I tly 



produces a peculiai gall, which is charac- 



.f thai - iiumlit • 



f< m:, , rail-Hie* pro- 



duced from uufertilizi i there I 



do males in existence. Thus Cynipt >, 



idcuintti < ». Back., which produces a 



>■ irall in the autumn, in the spring of 

 ■ succeeding lai « 1 » I « - 1 1 pro- 



duce galls disclosing a dimorphic form. Fig. aio.-Oaii-fly .,f 

 originally thought to be a distinct Bpecies, and Darned 0. q. >.. - 

 fiea by Osten Sacken. The autumn brood of this Cynips coi 



entirely of agamoua females, while the spring l>r 1 consists of t >• • 1 1 1 



males and females; there is thus an alternation of generations, and 

 till— is the case in many species. In son the t\v<> generations 



belong to what were originally described as separate gem ra. Tims 

 Ailler observed that the European v produces 



galls of a certain form mi the under surface of oak-leaves, the L r alls 

 tailing off in the autumn, and the By appearing in the early Bprmg. 

 It then deposits its egg* on the buds of the oak, which produce 

 upon the leaves and stalk- <<( the male dowers galls unlike tin - 

 the preceding autumn. M . the By which e: from 



them has been referred to a b< parate g< oua § \rum. 



This in turn lays eggs which produce the original N rus form; 



and the Neuroterus generation i e, while the 



Spathegasters are of both sexes 

 The gall-flies fall into two sections, the ; • true 



Fig. ili.—Bvania laevigata nd juipa. 



gall-flies (Psenides) and the guesl gall-flies I- ■ which are 



commensals «>r boarders living at the expens - dl-l 



with the peculiar genus Ibalia, while the secot lea the Figi- 



t ides, which are paras [n the sub-family 1 abdomen 



is elongate-ovate, compressed, with the apexm • ; oinled. 



