104 ORTHOPTEROUS GROUP INSARAE 



however, is approached in certain females of the plastic A . gracilipes 

 constricta. The species gracilipes with its geographic race constrida 

 is the most plastic unit in the genus, probably on account of its 

 adaptability, ranging as it does over the greater part of the territory 

 in which the genus occurs. A number of the characters which are 

 important as diagnostic in other forms vary appreciably in this 

 variable type. 



Group B is composed of three elements; insaroides apparently 

 primitive in a number of respects, as the form of the pronotum and 

 the stridulating field of the male tegmina ; phalangiiwi and grallator 

 specialized in the development of the extremity of the cephalic and 

 median femora and the extreme angulation of the caudal margin 

 of the disk of the pronotum, macropterous, however, in both sexes, 

 and sefnialata which has a tendency toward angulation at the apex 

 of the stridulating vein of the male tegmina and an approximation 

 toward group C in the slenderer ovipositor. 



Group C is quite homogenous, carita standing slightly apart from 

 the others in the lesser degree of brachypterism in the female and 

 the lesser degree of production of the apex of the stridulating vein 

 of the male tegmina. The crenulation of the abdominal segments 

 is not indicated {brevicauda) or decided {carita and lifnifera) . The 

 specialization of the sound-producing apparatus of the male reaches 

 its greatest extreme in this group ( i.e. limifera). 



Group D is very decidedly separated from the other forms of the 

 genus, differing in a number of features. The coloration and gen- 

 eral appearance of the single species comprising the group is 

 distinctive. 



Morphological Notes on Male Genitalia. — The supra-anal plate 

 presents three general types in this genus ; one, the more prevalent, 

 being more or less tongue-shaped, usually as long as broad, oc- 

 casionally with parallel sides and distad more or less rounded, 

 rather weakly or not at all sulcate proximad; another; found in the 

 species of group C, is distinctly transverse with the lateral and 

 distal margins more or less arcuate, and the third, found onl}^ in 

 arachnopyga, is large, slightly longitudinal, rectangulate, deeply 

 sulcate for the greater part of its length and recessed into the disto- 

 dorsal segment, which is rectangularly excised to receive it, a fea- 

 ture not found in any of the other forms. The cerci are in general 

 of similar form in all the species except those of group C, the distal 



