540 The University Science Bulletin. 



EXTERNAL ANATOMY. 



Apparently little work has been done on morphology within the 



family Cercopidae. In no case throughout the literature available 



for study has a thorough investigation of the structure of the entire 



body been made. One paper on the alimentary canal of a cercopid 



by Kershaw (1914), one on the respiratory system of a nymph of 



the Aphrophorinae by Sulc (1910) , and one by Metcalf (1916) on the 



wing venation of Cercopidae, are the most extensive works to be 



found. Other brief references to the morphology of the Cercopidae 



were found in a number of articles dealing with the homologies of 



certain special parts of the body among the families of Homoptera, 



namely, Taylor (1918) on the thorax, Kershaw and Muir (1922) on 



the genitalia of both sexes, Crampton (1922) on the male genitalia, 



and Hansen (1890) on the appendages and spiracles. One other 



article on the structure of Aphrophora spumaria by J. 0. Harper 



(Science Gossip, 1874) concludes the list, but is of little value 



morphologically. 



THE HEAD. 



The terminology used in the discussion of the head is based mainly 

 on that of Comstock and Kochi (1902) , Martlatt (1896) , and Funk- 

 houser (1917). 



The deposition of chitin is fairly heavy and uniform throughout 

 the exoskeleton of the head. In fact, both dorsal and ventral 

 surfaces are hard and brittle making dissection very difficult with- 

 out first boiling in KOH. 



A dense prostrate pubescence, consisting of thin, grayish hairs, 

 covers the entire surface of the head. This gives the appearance of 

 a grayish bloom, which partly conceals the coloration of the insect. 



The head of Lepyronia quadrangular is (Say) resembles the other 

 Homoptera in most of the essential parts, although it resembles some 

 more closely than others. Perhaps it is more nearly like the Cicad- 

 idae and Cicadellidae when such points as the position of the head in 

 relation to the body and the shape and comparative size of the 

 sclerites are considered. The protruding, enlarged sclerite with its 

 striated borders, commonly called the front, of Lepyronia instantly 

 reminds one of the larger, homologous sclerite in the cicada. Like- 

 wise the heads of both these insects lie in nearly the same plane as 

 the body, which condition is seldom found in other Homoptera out- 

 side of the Cicadellidae. In Lepyronia quadrangularis, however, a 

 flattening of the head dorsoventrally has taken place, with the result 



