Biology of the Membra cidae of the Cayuga Lake Basin 365 



to the types of structure in the various parts of the body or in the organs. 

 In regard to a few of the tissues, however, some space maj^ l)e given to 

 the discussion of special conditions tliat appear to be of interest in the 

 family. 



As of particular note the development of the chitin may be mentioned. 

 This is deposited very strongly over the entire pronotum, but very weakly 

 on the remainder of the body, due, no doubt, to the fact that the meso- 

 and the metathorax and the abdomen are usually protected by the 

 exaggerated dorsum of the prothorax. The undersurface of the entire 

 body is soft, the beak, along with the interior body parts, being well 

 chitinized. Internally the bases of the genital organs, and often the 

 filter chamber of the intestine, show evidences of chitinization. 



There is a surprisingly small amount of fatty tissue in both nymphs 

 and adults. This might be explained in the latter case by the active 

 life of the insect, but the nymphs are decidedly sluggish and heavy-bodied 

 and the significance of the lack of fat in these forms is not apparent. 



The musculature of the entire body is unusually well developed. Not 

 only does this apply to the leg muscles, where such development might be 

 expected, but it is equally true of the wing muscles and the muscular 

 layers of the abdomen. 



The connective tissue membranes thruout the body are strong and 

 heavy. This is particularly true of the diaphragm-like di\'ision walls 

 between the segments of the thorax, between the head and the prothorax, 

 and between the metathorax and the abdomen. The intestine is likewise 

 surrounded at various parts by heavy connective bands. 



The nervous system is very poorly developed, and nerve tissue, aside 

 from the ventral nerve cord, is hardly to be distinguished. This fact 

 has been mentioned as one of the evidences of the low phylogenetic rank 

 of the family. 



LIFE HISTORY 

 appearance in spring 



Since most of the local species of Membracidae spend the winter in the 

 egg stage, the first evidence of the family in the spring is the appearance 

 of nymphs from the winter eggs. This occurs during April and May 

 for most of the species, but a few delay emergence until June. Only 

 one species, Ceresa hasalis, regularly hatches as late as July. The approxi- 



