June, I9IS-] HeBARD : AMERICAN SpECIES OF MiOGRYLLUS. 



113 



rence, but pronounced degree when present, of this speciaHzation in 

 this and other species, is a feature the sokition of which will prob- 

 ably require both extensive field studies and breeding experiments. 



In the present species a large ovoid membranous foramen is 

 present on the internal face of the cephalic tibia in all macropterous 

 specimens, but in the micropterous examples before us this place is 

 indicated merely by a slight unmodified depression of the chitin. As 

 in the other species of the genus, opposite this point on the outer 

 face, a larger, nearly elliptical, membranous foramen is always 

 present in the adult condition. 



Measurements (in Millimeters) of Extremes. 



The extremes of body length are; males, 12. 8-16, females 12.7- 

 14.2 mm. In the series from Brownsville, the caudal femora average 

 somewhat longer and in the females the ovipositor averages shorter 

 than in material from the southwestern United States, but, consider- 

 ing the known variability within the species, it appears wholly un- 

 likely that further material will exhibit sufficient constant geographic 

 variation to warrant the recognition of an eastern race. 



The general coloration of the present insect is pale yellowish 

 brown, marked with a darker shade. The abdomen is dark, with 

 two meso-lateral bands of paler brown which vary from decidedly 

 wide to moderately narrow in different individuals. 



Of the material here studied probably nearly all the macropterous 

 individuals were taken when attracted to lights at night. It is a dif- 

 ficult matter to capture this very active insect in its native environ- 

 ment under rocks, stones or various rubbish, and this undoubtedly 

 accounts for the scarcity in collections of micropterous material. 



