142 NORTH AMERICAN BLATTIDAE 



margin transverse; seventh with surface moderately convex and with dislal margin 

 convex but truncate mesad, thus concealing (in normal position) all but lateral 

 margins of eighth segment and proximo-mesal portion of supra-anal plate. Supra- 

 anal plate with free margin between the cerci convex, but (normally) showing feeble 

 angulations disto-laterad.232 Cerci elongate and slender, with disto-lateral angles 

 of proximal joints slightly produced^^^ and lateral margins moderately crenate dis- 

 tad. Genital hook very short and broad, with distal half sharply recurved, elon- 

 gate oval and tapering to acute apex. Subgenital plate much as in divisa. Ex- 

 posed folded ventral portion of eighth dorsal abdominal segment extremely variable 

 in the series, in length (normally) less than that of exposed portion of seventh ventral 

 abdominal segment. 



Characters of Female. — (Mount Airy, Philadelphia, Pennsylvania.) Size large, 

 form decidedly robust. Head larger and more evenly rounded than in male, with 

 face slightly more dei)lanate than in this sex of the species of the genus, except 

 divisa.^^^ Interocular space (in the series) slightly less than (normal) to slightly 

 greater than that between antennal sockets. Pronotum more ample and decidedly 

 wider than in male, with greatest width near caudal margin and latero-caudal angles 

 much more sharply rounded; sulci of disk subobsolete.^^^ Tegmina reduced, cov- 

 ering (normally) more than half the dorsal surface of the abdomen. ^se Sixth dorsal 

 abdominal segment broadly and feebly concave laterad, broadly but more decidedly 

 convex mesad. Supra-anal plate (normally) with lateral margins nearly straight, 

 convergent, showing a slight concavity just beyond' bases of cerci, to the rather 

 sharply rounded apex.^^^ Cerci shorter than, but otherwise much as, in male.^'s 

 Subgenital plate strongly convex, with distal margin very broadly rounded and 

 feebly irregular. 



232 Even greater variation than in divisa is found, and although the condition described 

 above is the more usual in the series before us, it is evident that in large series individuals 

 will be found with this plate ranging from convex-truncate to evenly convex and con- 

 vex-trigonal. 



233 In the majority of western specimens these angles are decidedly produced, as much 

 as in nhleriana. In the present species, however, this is not sufficiently constant to 

 warrant recognition, except as an interesting individual variation having some geographic 

 significance. 



^^'^ See footnote 216. 



235 In many females of the series before us, the sulci of the pronotal disk have entirely 

 disappeared. 



236 Every degree occurs from a decidedly reduced type (particularly in material from 

 Iowa and Nebraska to Texas) in which the tegmina are but little longer than tlic jirono- 

 tum, to a partially caudate type (one specimen; Natchez, Mississippi) in which the 

 sinistral tegnien alone extends well beyond the apices of the cerci, but is not as ample 

 as in the male. 



237 In the supra-anal plate, the lateral margins vary to a condition in wiiich they are 

 concave in large portion, the apex varying from bluntly to sharjily rounded. 



238 See footnote 233. 



