12 GUIDE TO ORTHOPTERA 



BLATTIDAE. 



Only about half the subfamilies of Blattidae occur in North 

 America north of Mexico, and half of those that do occur are 

 represented only by one or two commercially introduced species. 

 A single subfamily is fairly well represented by indigenous species, 

 and of all the genera only one is confined to the United States. 

 Many of the genera occur in both the Old and New Worlds. 



Subfamilies of Blattidae. 

 A ^ All the femora, or at least the middle and hind pair spined 

 beneath. 



h^. Last ventral segment of female abdomen relatively plane, 

 not compressed-rostrate, entire, not fissate ; fore femora rarely 

 armed beneath on the inner margin with many distinct spines 

 next the genicular spines, and if so then the styles are unequal 

 or one is wanting. 



^ Pronotum and tegmina glabrous ; tarsi without pulvilli ; 

 median vein of wings sending but few veinlets to the apex, 

 the radial many parallel, generally simple veinlets to the 

 costal margin. ...... Blattinae. 



c ^ Pronotum and tegmina more or less pilose ; tarsi provided 

 with pulvilli ; median vein of wings with many branches, the 

 radial emitting relatively few and more or less irregular 

 veinlets to the costal margin. . . Nyctohorinae. 



h '^. Last ventral segment of female abdomen compressed-ros- 

 trate, fissate so as to be bivalved ; fore femora armed beneath 

 with many spines on the inner margin, throughout nearly or 

 quite the whole length or at least in the middle ; styles of equal 

 length. ....... Periplanetinae. 



A^. The middle and hind femora, and usually all the femora, 

 without spines beneath.* 



b ^ The supraanal plate more or less produced in both sexes, 

 its hind border emarginate. 



c 1. A distinct arolium between the claws ; pronotum and 

 tegmina glabrous ; anal field of wings multiplicate when at 

 rest. ....... Panchlorinae. 



* Bristles or hairs must not be mistaken for spines. 



