2l8 NORTH AMERICAN BLATTIDAE 



caudal tibiae bearing six apical spines.) (Size large. Dextro-dorsal and dextro- 

 ventral concealed genital plates are two smooth, brief, corneous lobes; concealed 

 genital hook facing inward in form of interrogation point and not enlarged near 



apex.) Homoeogamia mexicana Burmeister ^^^ 



AA. Marginal and scapular fields of elongate tegmina narrow. Subgenital plate 

 without styles. 



B. As in first parentheses under A, but with cephalic femora lacking a distal 

 spine on the ventro-cephalic margin. Concealed genital hook curved inward. 

 Subgenital plate not specialized. 

 C. Concealed genital hook not enlarged near apex. Dextro-dorsal concealed 

 genital plate, a narrow, elongate lobe; dextro-ventral concealed genital plate 

 very large, with surface concave (and margins irregularly rounded). 

 D. Size large to medium. Dextro-ventral concealed genital plate with 

 margins very broadly and strikingly shagreenous. Interocular space nor- 

 mally about half as wide as interocellar space. 



Arenivaga bolliana (Saussure) 

 DD. Size medium to rather small. Dextro-ventral concealed genital plate 

 with margins very briefly and obscurely roughened or smooth. •''''■' 



Arenivaga rehni new species 

 CC. Concealed genital hook enlarged near apex, barbed. Dextro-ventral 

 concealed genital plate, a very large, oval lobe, with surface strongly convex 

 (hiding in part the smaller dextro-dorsal concealed genital plate). 

 D. Size medium to rather small. Dextro-ventral concealed genital plate 

 without projection. Interocular space normally less than interocellar 

 space. Marking of pronotum not pictured .. Arenivaga erratica Rehn 

 DD. Size rather small. Dextro-ventral concealed genital plate with elon- 

 gate, heavy spike, directed meso-dorsad. Interocular s])ace normally sub- 

 equal to interocellar space. Marking of pronotum pictured, except in 



suffused condition Arenivaga apacha (Saussure) 



BB. Supra-anal plate not produced, distal margin weakly convex. Cerci not 

 jointed, not evenly tapering. Femora with margins and genicular areas very 

 hairy but unarmed. Cephalic tibiae bearing eight spines. Median and caudal 

 tibiae bearing seven apical spines. Concealed genital hook curved outward. 

 Subgenital plate with specialized organ proximo-sinistrad. 



353 We have omitted reference to guttipennis and aequalis in the present key, names 

 very probably synonyms of mexicana. See discussion under genus Homoeogamia, page 



221. 



^^* Owing to the lack of materia! over the greater portion of this species' distriliution, 

 we are unable to give the normal width of the interocular space. Decided variation 

 occurs, see page 230. 



