CHAP. XIII.] CATERPILLAR PESTS OF CROPS. 131 



persistent robbers of honey and are often found inside bee-hives. 

 But, with these few exceptions, it is only in the larval or caterpillar 

 stages thai the Lepidoptera require consideration as crop-pests. 



A ■ aterpillar is easily recognizable as such by the presence of 

 prolegs or false legs, stout fleshj legs situated in pairs on the 

 seventh and succeeding segments of the body, the head being 

 reckoned as the firsl segment. Except in the case of a few of the 

 more generalized Microlepidoptera, of no economic importance, 

 more than live pairs of prolegs are never present and the number is 

 frequently smaller. This point immediately distinguishes cater- 

 pillars from the larvae of beetles, wasps and flies, in which no 

 prolegs are present, and from those of the leaf-eating sawfiies, 



lac. lillar of Death's-head Moth (Acherontia 



Lterpillar may do considi to Erythrina and other plants 



which are superficially verj like caterpillars but which possess more 

 than five pairs of prolegs. In some cases the number of : 

 may he reduced to two pairs when the caterpillar progress 



reaching forward and grasping an object with its thoracic (true) 

 le^s and then, arching up it- intermediate segments, brings forward 

 its hinder end and grasps the resting surface: the two extremities 

 are therefore alternately approximated and separated by the whole 

 length of the body. Such a structure and method of progn SS 



9-A 



