MORGAN HEBARD 77 



Though this key may be useful in determining the majority of 

 specimens encountered, variation in all the features known for the 

 separation of females constantly occurs. I'se of a key. without 

 reference to the known specific variability and unusual features, 

 can only lead to occasional serious mistakes. This is particularly 

 true in such species as divisa and pensylvanica , where sufficient 

 variation occurs in each, toward the other, to make determination 

 of occasional specimens extremely difficult, even when the specific 

 range of variation in all features is carefully considered. 



The genus is distributed generally over the I'nited States, being 

 absent apparently only in the Cordilleran region from Colorado 

 northward and in almost the entire area of the Great Basin. Few 

 species reach beyond the Canadian boundary, and these only in 

 the East. The most northern records for the genus are Orono, 

 Maine; Abbotsford and Montreal, Quebec; Sudbury, Ontario; 

 Polk County. Wisconsin; eastern Nebraska; Fort Davis, Texas; 

 Prescott, Arizona; \'erdi. Nevada, and Oregon. Southward the 

 genus will assuredly be found in adjacent Mexico, probably quite 

 extensively over the northern plateau and mountains. For those 

 regions, however, the genus is yet known from but a single "Lower 

 California" record of americana. 



In the present study of Parcoblatta, 2852 specimens have been 

 examined, of which 2025 are in the Philadelphia collections. 



Parcoblatta bolliana (Saussure and Zehntner) (Plate III. figures i to 3.) 



1893. Ischnoptera bolliana Saussure and Zehntner, Biol. Cent.-Amer., Orth., i, 



p. 4. [d ■■ New Mexico, and Texas.] 

 1904. Kakerlac schaefferi Rehn, Psyche, xi, p. 72. [ 9 , Esperanza Ranch near 



Brownsville. Texas.] 



The above synonymy has been indicated by Rehn and Hebard,"^ 

 schaefferi having been based on the then unrecognized female of 

 this species. 



This insect is very distinct from any other of the genus. The 

 males of this species and of P. desertae differ, from all other known 

 males of the genus, in the unspecialized median and dorsal abdomi- 

 nal segments. The females, with those of P. americana, show 

 the greatest tegminal reduction found in this sex of the genus; 



1" Proc. Acad. N'at. Sci. Phila., 1910, p. 449, (1910). 

 MEM. AM. ENT. SOC, 2. 



