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lI^rc^aciou0 d Iparaeitic lenemiea of Bpbibee 



(incluMuG a Stu&^ of HDi^per^patasttes). 



By H. C. A. Vine. 

 Part IV. Plates VII. and VIII. 



THE Linnsean order, Hemiptera, to which the Aphides them- 

 selves belong, includes some species which are actively 

 aphidivorous in all stages of their existence. 



Like certain genera of the Neuroptera, this order is distin- 

 guished by the ' incomplete ' character of the metamorphosis 

 which the various species undergo, the adult differing from the 

 larva form generally only in the possession of wings and in minor 

 structural details, which are, however, of a nature to make the 

 resemblance often difficult for an inexperienced eye to trace, 

 especially in such genera as Phyllaphis, Phylloxera^ Calocoris, and 

 Caps2is. The habits of the larva and the nature of its food are 

 generally the same as that of the imago, and the acquisition of 

 wings rarely involves any change in environment except such as is 

 due to an alternation of hosts. These circumstances, together with 

 the coriaceous nature of the anterior pair of wings, led Linnaeus to 

 unite these insects in a single order with the Orthoptera. 



The totally different structure of the mouth parts rendered 

 some further division necessary, and Latreille at a later date 

 effected the separation of the incongruous groups, the distinguish- 

 ing character of the Hemiptera since his time being the prolonga- 

 tion of the mouth into a fleshy rostrum, or beak, supporting four 

 setae, which are considered to be the homologues of the mandibles 

 and maxillae in other insects. The possession of this suctorial 

 apparatus has led some naturalists to adopt the designation of 

 Rhynchota, or * beaked insects,' for the group in preference to 

 the older term, Hemiptera. Similarly to the Neuroptera, the 

 Hemiptera have been sub-divided into two great sections on the 

 basis of their characteristic wing-structure. The best-known of 

 these sub-orders (the Hemiptera- Homoptera) includes the Aphides, 

 Cicadas, Thrips, Coccidae, and other less-known groups, and its 



