46 ORTHOPTEROUS GROUP INSARAE 



tenuate and lacking the distinctive dorsal abdominal marking 

 which is present in all of those species, but in appearance they 

 show a decided general similarity to those species and agree with 

 the first group also in the character of the proximal portion of the 

 cephalic tibiae, which is more swollen and narrows more abruptly 

 below the tympanum than in any of the other species of the second 

 group. All of the forms found north of the Rio Grande, I. elegans, 

 elegans consuetipes, apache, covilleae and gemmicula, show a general 

 relationship, one of the most striking features of which is the pale 

 green coloration, more or less maculate in all but I. apache. To 

 the second group also belongs I. lamellata, known only from Lower 

 California. The remaining species, /. ahhreviata, is a very aber- 

 rant member of the second group, unique in form of pronotum, 

 tegmina and male subgenital plate; it is known only from central 

 Mexico. 



Notes on Spination. — The armament of the distal portion of the 

 cephalic and median femora is constant in the present genus and 

 furnishes important characters. It has, on the other hand, seemed 

 undesirable to include in the specific descriptions data concerning 

 the armament of the ventro-cephalic margins of the cephalic and 

 median femora, (the ventro-caudal margins are always unarmed) 

 owing to the fact that the small spines there found are exceedingly 

 variable in number and are, not infrequently, wholly absent in 

 species which usually possess them. We have, however, noted 

 that I. prasina bears in most cases the greatest number of such 

 spines (as high as 6-5 for the cephalic and 5^ for the median 

 femora), while individuals of the other species, belonging to the 

 group of which I. tolteca is a member, are usually supplied 

 with several spines on each of these margins.^ The remaining 

 species of the genus have in most cases one or two of these spines on 

 each of the ventro-cephalic margins of the cephalic and median fem- 

 ora with the exception of apache, ahhreviata, gemmicula and covilleae 

 which species have these margins unarmed. 



Morphological Notes on Genitalia.— Important characters of the 

 male subgenital plate exist, as given in the above classification. 

 Cereal characters are present in this genus and may be used to 

 separate a number of the species. The cerci are, however, not 

 forked or serrate in any of the species, the differences lying in their 



* See footnote under description of /. phthisica, p, 47. 



