28 Annals Entomological Society of America [Vol. VII, 
H. The study of the Malpighian vessels of species of 
Braconids and Ichneumons, shows tubules with cells not larger 
than those of the Chalcids and inquilines. The mode of degen- 
eration however, appears similar to that found in Dryophanta 
erinacel. 
4. The theory of the relation of the oenocytes to gall 
production as urged by Rossig is not confirmed by this study. 
A. His argument is without support from the data furn- 
ished by Dryophanta erinacei, Dryophanta polita, and Holo- 
craspis globulus. The oenocytes of the Eurytoma pupa and 
the larva, Synergus erinacei, are relatively larger than those 
found in a larva of similar size of Dryophanta erinacei, while 
the oenocytes of Nematus pomum and Trypeta solidaginis 
were equal to those found in Dryophanta erinacet. 
B. The oenocytes do not secrete urates. Perez has shown 
this to be true in the ants, and Berlese appears to have now 
accepted this view. In the oenocytes of the various species 
studied, we have found no urate crystals or globules. 
C. Since we do not know the chemical character of the 
secretion in the oenocytes, and since there appears to be no 
unusual activity in these cells during the molting and pupating 
periods of these species under consideration, we are not con- 
vinced that they take the place of the Malpighian tubules 
during these periods. 
Until we know the chemical character of the secretion pro- 
duced by the oenocytes, we shall only deal in speculation as to 
the réle of these cells in insect life. 
In conclusion I wish to thank Professor Comstock and 
Dr. W. A. Riley for the direction, and criticism so freely given, 
and especially Dr. Riley, at whose suggestion the work was 
undertaken, and whose assistance was invaluable throughout 
the entire study. 
