no. 3628 GENUS PARANTHESSIUS — HUMES 9 



The differences observed between these two new species appear to 

 be constant among the specimens studied, without overlap. The 

 swollen prosome in the female of P. mesodesmatis occurred in both 

 ovigerous and nonovigerous specimens. Bocquet and Stock (1959) 

 stated that the prosome in Paranthessius tends to become larger and 

 more swollen with the age of the females, doubtless because of the 

 pressure exerted by the ovaries. In the preserved specimens of P. 

 mesodesmatis it was impossible to separate the females by age since 

 there was no way of being certain that egg sacs in some cases had not 

 accidentally been broken off. The single less tumid mature female 

 mentioned above may represent an individual that had not yet pro- 

 duced egg sacs. 



2^,9-420— 6T- 



