64 THE LIFE-STORY OF INSECTS [CH. 



cuticle, so that the grub is often described as ' fleshy.' 

 This type of larva is by no means confined to certain 

 families of the beetles, it is frequently met with, in 

 more or less modified form, in two other important 

 orders of insects, the Hymenoptera and the Diptera. 

 Among the Hymenoptera this is indeed the predomi- 

 nant larval type. We have just seen that a cater- 

 pillar is the usual form of larva among the saw-flies, 

 but in all other families of the Hymenoptera we find 

 the legless grub. A grub of this order may usually 

 be distinguished from the larva of a weevil or other 

 beetle, by its relatively smaller head and smoother, 

 less wrinkled cuticle; it strikes the observer as a 

 feebler, more helpless creature than a beetle-grub. 

 And it is of interest to note that this somewhat 

 degraded type of larva is remarkably constant through 

 a great series of families gall-flies, ichneumon-flies, 

 wasps, bees (fig. 18), ants that vary widely in the 

 details of their structure and in their habits and 

 mode of life. Almost without exception, however, 

 they make in some way abundant provision for their 

 young. The feeble, helpless, larva is in every case 

 well sheltered and well fed ; it has not to make its 

 own way in the world, as the active armoured larva 

 of a ground-beetle or the caterpillar of a butter- 

 fly is obliged to do. 



Among those saw-flies whose larvae feed through- 

 out life in a concealed situation, we find an interesting 



