170 DERMAPTERA AND ORTHOPTERA FROM SINALOA, MEXICO 



This is the only species of the Group Ischnopterae known to 

 us, where less than three heavy distal spines on the ventro- 

 cephalic margin of the cephalic femora occur. Such a condition 

 is found in about half of the genera of the Group Blattellae. In 

 none of the other American species of the Ischoptcrae, with which 

 we are familiar, are the tarsal claws asymmetrical. This occurs in 

 a very few genera of the Blattellae, 



Pseudomops septentrionalis Hebard 



1917. Pscudo)iwps seplentrionalis Hebard, Mem. Amer. Ent. Soc, no. 2, 

 p. 156, pi. VI, figs. 5 to 8. [cf, 9 ; Brownsville, Texas."] 



Venvidio, VI, 30 to IX, 2, 1918, 18 cf , 3 9 . 



The present series shows very little color variation. In some 

 the limbs, however, are much darker than in others. The 

 pronotum shows a difference from the usual Texan material in 

 having the lateral and cephalic margins usually very slightly 

 and inconspicuously paler than the adjacent portions, in a few 

 specimens only, is some approach to the Texan series shown in 

 this feature of coloration. 



Very close agreement is shown by the general structure, but 

 in one feature of the concealed genitalia we find, in certain 

 individuals only, an extraordinary variation. In this species 

 the paired plate beneath the supra-anal plate has the sinistral 

 portion produced in a large, irregular, lobate patelliform pro- 

 jection, directed mesad, with surface armed with a few minute 

 teeth meso-distad; the dextral portion is produced in a heavier, 

 irregularly rounded patelliform projection, l)earing mcsad on its 

 ventral surface a large cylindrical process, which, directed ventro- 

 sinistrad, curves weakly sinistrad, tapering to its acute apex.^*^ 

 In the Texan material examined, as in individuals of the present 

 series, this is the only process developed on this plate; in other 

 specimens from Venvidio the plate, on the same margin but 

 nearer the l)ase of the dextral style, is jiroduced in anotlu^r, de- 

 cidedly smaller, but generally similar process. DiffercMrliation of 

 the concealed genitalia of similar degree, we believe may in most 

 genera be considered as a criterion of full specific differential 

 value. In the present case, however, it a])])ears almost certain 

 that the difference noted is attributable wiiolly 1o individual 

 variation. 



1' Material from fourteen Texan localities and from Saltillo, Coahuila, and 

 San Jose, Tamaulipas, is also recorded. 



** In our original diagnosis we called this a genii al iioolv, slating that it 

 curved inward, i. c. toward the longitudinal axis of the body. 



