ART. 18. NOTES ON CYNIPID WASPS — WELD. 5 



author. The tendency toward dwarfism in Ibalia must be consid- 

 ered, therefore, not as due to lack of food, but an expression of a 

 normal tendency in the species to depart from the type. The best 



measure of this variability is the standard deviation which defined 

 the shape of the frequency curve much as the radius defines a circle. 



UOPTERON TARSALE Ashmead. 



The Academy of Natural Sciences, Philadelphia, has one female 

 determined by the writer as this species by comparison with Ash- 

 20107— 22— Proc. N. M. vol. 61 24 



