Biology of the Membra cidae of the Cayuga Lake Basin 363 



separating the wing tips, and for that reason is the best adapted of all 

 the genital parts for systematic work. 



On the whole the male genitalia afford good taxonomic characters. 

 The parts are simple and easy to dissect. The relative position of the 

 plates and the structure of the individual pieces show sufficient variation 

 thruout the family, and are constant enough within a genus, to furnish 

 valuable data at least to supple- 

 ment the more evident charac- 

 ters of the exoskeleton. 



Crop 



INTERNAL ANATOMY OF THE 

 MEMBRACIDAE 



. Elsopfic7Cfus 



— F/Iier chamber 



_ Ascendi nq 

 mid-infesfine 



Small inleCifine 



Urinarif iubule 



The internal anatomy of the 

 membracid does not, on the 

 whole, differ enough from that 

 of other Hemiptera to warrant 

 special discussion. The diges- 

 tive system, however, is peculiar 

 and shows some of the striking 

 characters described by Ker- 

 shaw (1913) for the species 

 Tricentrus albomaculatus Dist. 

 of the subfamily Centrotinae. 

 This exotic species shows a for- 

 mation of the mid-intestine 

 much resembling that described 

 by Witlaczil, Lang, and Pack- 

 ard for the Psyllidae (Packard, 

 1898:320). 



No species of the Centrotinae have been available for dissection locally 

 and the specimens examined in the course of this study have all been 

 from the subfamily Smiliinae. These show some decided variations 

 from the type described by Kershaw, the most noticeable difference 

 being in the nmnber and position of the urinary tubules. 



The alimentary canal is short and much twisted (fig. 42) and the various 

 parts are strikingly distinct in size and structure. The short esophagus 

 opens directly into the crop, wliich is very large and has a peculiar twist 



Recium 



Fig. 42. structure of alimentary canal 



