SAWFLIES 



511 



country, but little known, and few persons recognise a sawfly as 

 such. They are usually of small or moderate size, and the 

 numerous species have a great family resemblance. This remark 

 requires some qualification in the case of the Cimbicides, they 

 being Insects of larger size — usually surpassing the honey-bee — 



of more robust structure, 

 and with greater powers of 

 flight. 



The antennae are re- 

 markably variable in form 

 and structure. Cameron 

 considers that nine should 

 be taken as the normal 

 number of their joints ; 

 but there are only three 

 in Hylotoma, while in Lyda 

 there may be forty or more. 

 The head is usually held 

 closely applied to the 

 thorax, but is really borne 

 on a neck capable of much 

 elongation (Fig. 332). 

 The pronotum forms a 

 part of the alitrunk, but is not soldered thereto. Usually the 

 presternum is more or less completely concealed by the side- 

 pieces, but in Cimbicides it is larger and conspicuous, the side- 

 pieces being in this group smaller than usual. The dorsal 

 pieces of the mesothorax have their relative proportions different 

 to what we find them in the other families of Sessiliventres, and 

 even in most of the other Hymenoptera. There is first an 

 antero-median lobe of triangular shape projecting, like a wedge, 

 far backwards, into the great lateral lobes. These latter form 

 the larger part of the area of the mesonotum ; they meet together 

 in the middle line, and behind are separated by a deep depression 

 from the posterior lobe, or scutellum of the mesothorax, which 

 is frequently divided into two parts, the anterior being the so- 

 called scutum. The pieces of the metanotum are short and 

 obscure, owing to the great unevenness of their parts ; on each 

 side of the middle there is a small membranous space of pallid 

 colour. The cenehri, as these spaces are called, are, in Lyda, 



Pig. 343. — Lophyrus pint. Britain. A, Larva ; 

 B, ventral aspect of pupa ; C, imago, male- 

 (After Vollenhoven.) 



