HYMENOPTERA 



433 



has developed, and for the highly evolved condition which para- 

 sitism has reached. 



Specialization of structure is evidenced in the mouth parts of the 

 Hymenoptera. The biting mouth parts of the phytophagous and 

 carnivorous sawflies closely resemble those of the cockroach. In the 

 wasps, e.g. Vespa, which are predaceous, the mouth parts are 





j 



Fig. 322. Caterpillar of Lepidoptera, A, B, C, and of Hymenoptera, D, E. 

 A, Larva of Tryphaena pronuba. B, Its head capsule. C, An abdominal leg. 

 D, Larva of apple sawfly, Hoplocampa testudinea. E, Head capsule of latter. 

 an. antenna; dp. clypeus;/r. frons; lb. labium; Ibr. labrum; nid. mandible; 

 mx, maxilla; oc. ocellus; v. vertex. 



also adapted for licking. The maxillary laciniae are reduced but the 

 galeae are enlarged into broad setose membranous lobes which absorb 

 juices. A correspondingly large bilobed glossa occurs on the labium. 

 The next important line of evolution is that concerned with the 

 development of a mechanism for obtaining juices from deeply placed 

 nectaries of flowers. For this purpose, e.g. in ApiSy the honey bee 



BI 38 



