234 STUDIES IN AMERICAN TETTIGONIIDAE (oRTHOPTERA) 



AAA. Caudal tibiae armed at distal extremity with one pair of spurs, the 

 dorsal and ventral pairs of spurs being absent. (Agreeing with Anarthropus 

 in this respect, but differing in the armed prosternum and annament of the 

 cephalic and median tibiae, the ventral margins of which are armed with seven 

 to eight well spaced spines.) (Subgenus Aphauropus) 



(Form robust. Vertex not decidedly produced, not ascending, fastigium of 

 vertex two-thirds width of proximal antennal joint. Convex callosity of 

 lateral lobes exceedingly broad. Tegmina greatly aborted and whollj- con- 

 cealed by pronotum, wings absent. Ventral margins of caudal femora 

 unarmed.) leptopterus new species 



In the above key it must be noted that only the usually most 

 useful and also the most distinctive characters are given; in 

 numerous cases material can only be determined properly through 

 careful consideration of all the specific details which are given, 

 as far as we are able, in the specific treatment. The figures are 

 of great importance in showing frequently complicated differences 

 very difficult to describe clearly, and also degrees of difference, 

 while for females only characters common to both sexes will be 

 found in the above key, the characters peculiar to that sex being 

 discussed in the specific treatment, shown by figures, and tabu- 

 lated in part on pages 237 to 239. 



Many species have individual characters of decided value, 

 which in a key would be cumbersome and confusing. Some of 

 these are: the depth of the fastigium of the vertex and the form 

 of its lateral margins, the shape of the lateral lobes of the pro- 

 notum and the humeral sinus, the minor specific differences of the 

 male tegminal tympanum, the spination of the genicular lobes 

 of the caudal femora and the coloration of the genicular areas of 

 the same, the general though obscure pattern of coloration in 

 species not strikingly marked and the length of the styles of the 

 subgenital plate. 



Extremely slight variations are found which cannot be wholly 

 overlooked, but which can hardly be considered in the treat- 

 ment of each species without giving them undue emphasis. 

 Such is the fact, only determinable after examination of large 

 series, that in species having both macropterous and brachyp- 

 terous forms, the latter type is almost always accompanied bj^ a 

 slight pronotal change, the dorsum of the pronotum being usually 

 slightly less produced caudad, with a proportionate reduction 

 in the depth of the humeral sinus and the caudal margin of the 

 lateral lobes becoming slightly less sinuous than in the macrop- 

 terous condition. 



