Biology of the Membra cidae of the Cayuga Lake Basin 295 



The strict diagi'aimnatic arrangement, however, would show the position 

 of the famihes as follows: 



Fiyf/qorldoe 



Cercop/c/ae 



Membrcrc/cfae 

 C/ccTC^/c/ae 



In defense of the low position here assigned to the Membracidae the 

 following points may be offered: 



1. The entire sensory system is most poorly developed. The antennae 

 are so minute as to be in most cases hardly visible and are but feebly pro- 

 vided with sensory apparatus. The responses of the insects to stimuli 

 are exceedingly slow or entirely wanting. 



2. The wings are extremely generalized. In a former paper by the 

 writer (Funkhouser. 1913:92) it has been shown that the Membracidae 

 are in this respect even lower than the Cicadidae, which Comstock and 

 Needham (1899:243) have pronounced the most conservative of the 

 Hemiptera so far as concerns venation of the wings. 



3. The genital organs are simple. Little pi-ogress has been made in 

 developing these structures from the ancient t>'p(\ 



4. The pronotum, to be sure, is highly specialized, but it is not logical 

 to weigh these modifications of purely mechanical structure's against the 

 more important phylogenetic evidence offered by the sensory, motor, and 

 reproductive systems. 



EXTERNAL ANATOMY OF THE MEMBRACIDAE 



In a taxonomic study of the Homoptera the structure and homology 

 of the vai'ious sclerites of the exoskeleton have in many groups furnished 

 an excellent basis for classification. The following division of this study 

 is therefore offered in the thought that a knowledge of such structures 

 in the family Membracidae might prove valualile in systematic work, 

 and as an explanation in detail of the structures used as characters in the 

 preceding section in which technical descriptions are given. 



