134 NORTH AMERICAN BLATTIDAE 



the brief lateral portions of the eighth segment; this condition is 

 the more decided in pensylvanica. 



From those of the present species, females of pensylvanica are 

 usually separated with ease by their larger size, proportionately 

 broader pronotum, more solid colors, with lateral margins of pro- 

 notum more strikingly pale, while from east of the Appalachians the 

 tegmina are normally decidedly longer. Females of divisa from 

 central Georgia southwestward also usually have the head decid- 

 edly more flattened than in pensylvanica, but this feature shows 

 some variability, even in that portion of the insect's distribution, 

 and is of less value for material from the Atlantic coast. The 

 interocular width averages slightly less than that between the an- 

 tennal sockets in divisa, slightly more in pensylvanica. In spite of 

 these features, due to the decided individual variation found in divisa 

 and the very great plasticity in pensylvanica, rare females are most 

 difihcult to distinguish, as in them great convergence in many 

 features usually of distinct value occurs. 



Characters of Male. — (Raleigh, North CaroHna.) Size medium large, form mod- 

 erately robust. Interocular width subequal to that between the ocelli. 212 Ocelli 

 well defined. Inter-ocular-ocellar area flattened, with surface microscopically 

 roughened. Pronotum with greatest width (normally) mesad,^!^ but with lateral 

 margins from this point slightly more convergent cephalad than caudad, oblique 

 sulci of disk strongly defined. Tegmina and wings normal, fully developed: teg- 

 mina with lateral margins subparallel in mesal two-thirds; wings (in the series) 

 with one to three incomplete and five to seven complete rami of the ulnar vein.^i^ 

 Median segment supplied mesad with two decided ridges, which are weakly con- 

 vergent cephalad, with their cephalic extremities overhanging the cephalic portion 

 of the segment, which is there, and between, rather strongly concave, a low ridge 

 connects the two projections just caudad of the concave area; ventral faces of over- 

 hanging extremities of the projections very heavily clothed with short hairs, the 

 narrow ridge of the cephalic margin of the segment furnished mesad with numer- 

 ous hairs. Other dorsal segments unspecialized: sixth with distal margin trans- 

 verse; seventh weakly produced, with distal margin broadly convex, thus 

 concealing all but the lateral margins of eighth segment and proximo-mcsal 

 portion of supra-anal plate. Supra-anal plate with free margin, between the 



212 In the series slightly less to slightly greater than this widtli, in all <lisiinctly less 

 than the width between antcnnal sockets. 



213 Occasionally slightly caudad of this point. 



21^ In one specimen the median vein branches once; this dueto in<li\ idiial ^•ariatio^, but 

 the only instance of such in the material of the genus before us. 



