INSECT LIFE IN INDIA AND HOW TO STUDY IT. 117 



the way in which they are connected together. In all but the 

 Tenthredinidce and Siricidm there is a deep constriction between 

 what appears to be the thorax and the body (cf. figs. 87 c and 49). 

 The abdomen is thus said to be stalked.* 



The eggs when being laid pass through the hollow stabbing or 

 boring apparatus at the end of the body of the female, in many cases 

 a prick or cut being made in .an animal or plant with this instrument 

 for the reception of the egg. This apparatus may also serve as a sting 

 (e.g., in the wasp). 



The grubs are usually white in colour and blind (see fig. 38, a) ; only 

 in the Tenthredinidce and the Siricidce do they resemble the caterpillars 

 of the Lepidoptera (butterflies and moths) (cf. fig. 39). The larvae often 

 form cocoons to pupate in. 



One of the most remarkable facts connected with this Order is the 

 prevalence of parthenogenesis (or the production of young by the female 

 without the concurrence of the male) in a considerable number of widely 

 separated species. In some members of the Order it. is believed that the 

 reproduction is entirely parthenogenetic. In the gall-making Cynipidce, 

 parthenogenesis is frequently accompanied by alternation of generations, 

 a generation consisting of two sexes being followed by another consist- 

 ing entirely of females, which in its turn gives rise to a bi-sexual 

 generation. 



The Order is divided into two very distinct Sub-orders dependant 

 upon the manner in which the abdomen is joined on to the thorax, 



viz. : — 



I. — Hymenoptera Sessiliventres. — Insects with the abdomen broad at 

 the base, its first segment not completely joined to the thorax. 

 II. — Hymenoptera Petiolata. — The abdomen connected with what 

 appears to be the thorax by the slender joint forming a marked 

 constriction between the apparent thorax and the abdomen. 

 I. — Hymenoptera Sessiliventres. 

 The abdomen is not stalked but is nearly continuous in outline with 

 the thorax (see fig. 37, e). Trochanters are divided into two portions. 

 The saws or boring apparatus at the end of the body of the female are con- 

 cealed or only just visible. The larva has three pairs of thoracic legs and 



* This constriction really occurs in the first abdominal segment and not in the thorax. 

 This first abdominal segment is firmly fixed to the thorax, and the constriction occurs 

 between it and the second segment of the body. 



