INSECT LIFE IN INDIA AND HOW TO STUDY IT. 123 



thorax. This stalk may be long or short, but is always present. This 

 sub-order is divided into three series — 



1. Parasitica or Terebrantia, including the families Cynipidce, 



Chalcididce, Ichneumonidce, and Braconidce. 



2. Tubulifera — comprising the Chrysididce. 



3. Aculeata — including the families Apidce, Diploptera, 



Fossoria and Formicidce. 



Series 1. — Parasitica or Terebrantia. 

 The trochanters (the second joint of the leg) are of two pieces (cf. 

 fig. 34), and the female is furnished with an ovipositor at the extremity 

 of her body. 



Fam. IV. Oynipidse— Gall-flies. 



Small, frequently minute, Insects, usually black or pitchy in colour, 

 in which the abdomen is short and compressed, with an ovipositor 

 arising from the ventral surface. The mesonotum is often very convex 

 and has behind a prominent scutellum which projects so as to overhang 

 the metanotum and the median segment which are perpendicular. 

 The sculpture of these parts is often deep and very remarkable. The 

 wings have only a few cells in them aud have no stigma (a black patch) 

 on the anterior margins of the upper wings. The antennse are of 

 importance in identifying a cynipid. They are straight, simple, and 

 are composed of a few (12 — 15) joints. The larvse live either in galls, 

 on plants or parasitically in the bodies of other insects, either singly or 

 several together. The female bores into the living portions of plants 

 (stems, leaves, buds) by means of the spine at the end of the abdomen, 

 and deposits an egg in the hole 

 thus made ; later on, the plant 

 tissue swells up in different 

 ways owing to the irritation 

 set up by the larva feeding 

 upon the tissues. The different 

 forms of gall thus arising are 

 characteristic of different spe- 

 cies of insect. In many species 

 a regular alternation of a par- Fig. 41.— A gall-fly. 



thenogenetic and a true sexual generation exists, the two generations 

 being dissimilar and causing galls of very different appearance. 



