TYPE TRACHEATA. 



619 



The larvae of the Tenthredinidse, for example that of the 

 Pear-slug (Selandria), which feeds upon the leaves of the pear- 

 tree, resemble the caterpillars in possessing prop-legs, of 

 which there are as many as eight pairs. In the majority of 

 forms, however, owing to parasitism or to being in contact 



Pig. 343. — SpAex ichneumonea (from Packard). 



t , 



Fig 244. — Hypoderma iovis (from Packakd). 

 with an abundant supply of nutrition stored up by the parents 

 (Bees, Wasps) or to being fed and cared for by the workers 

 among the Ants, the larvae are maggotlike and almost or 

 entirely destitute of legs. The metamorphosis is complete, 

 the pupa being a pupa libera. 



15. Order Diptera. 



In this order, as the name indicates, but two wings are 

 present (Fig. 244), which are those of the mesothorax, the 



