138 Comparative Classification of Cynipidae. 



by Biorhiza renmn and Trigonaspis crustalis : here the 

 number of joints in the palpi varies ; Biorhiza renumhas 

 four maxillary and two labial joints, while Trigonaspis 

 crustalis has five maxillary and three labial. 



As regards the joints of the antennae their number 

 is usually the same in the two generations, except again 

 in the case of Biorhiza renum and Trigonaspis crustalis, 

 when the first has thirteen, and the second fourteen 

 joints in the antennae. There is, moreover, alwa3^s this 

 difference in the sexual generations, that the male has 

 one joint more in the antennae than the female. From 

 this it will be seen pretty clearly that any characters 

 based on the number of joints, either in the antennae or 

 in the palpi, are not to be relied upon. 



The intestinal system of the Cynipidae is simple, 

 uniform in the various species, and very limited in 

 its functions. My own observations agree with those 

 of previous observers, and I can confirm the state- 

 ment that the Cynipidae, in the perfect state, take 

 no nourishment of any kind, except a little water. The 

 winter generations almost all appear at a time when 

 vegetable life is dormant, and offers no sustenance ; but 

 even the summer generations take nothing except water. 



Observation shows that all the Cynipidae require 

 water, and imbibe it with pleasure. Unless frequent 

 opportunities of drinking water are afforded, it is 

 absolutely impossible to succeed in experimental breed- 

 ing. As regards the summer generations, I will not 

 deny that they do occasionally lick the juices which 

 they find on the leaves, but as a rule water is all they 

 want. On being opened the stomach and metenteron 



