68 ■ PROCEEDINGS OF THE ACADEMY OF [Jan., 



the earlier instar, while in the other stage, in all of the species repre- 

 sented in this condition, there is a more or less distinct indication of 

 an incipient lobe or tooth, this being most pronounced in durangensis 

 and catinata. In the latter this embryonic lol)e is more definitely 

 formed than in durangensis, consisting of an ovate vertical area of 

 relatively large size. In the closely related oreoeca, the incipient lobe 

 is not vertical, but horizontal in position. 



The male subgenital plate is very varied in form, the distal margin 

 ranging from truncate with lateral styliform processes to obomegoid 

 emarginate; the general form broad with the distal portion little 

 produced and narrowed, the lateral angles more or less blunted, to 

 an opposite jextreme, elongate, narrow, concave laterad with the 

 lateral angles acute, between which extremes are a number of modifi- 

 cations of one or the other. Quite curiously, there exists no correla- 

 tion between certain forms of cerci and certain forms of the subgenital 

 plate, forms nearly related in cereal structure, as oreoeca and catinata, 

 having very different subgenital plates. 



Morphological Notes on Female Genitalia. — The ovipositor ranges 

 in general form from the elongate, very slender, decidedly arcuate 

 type seen in gladiator, and the elongate robust type with a more or 

 less straight ventral margin as found in a number of species, to a 

 short, moderately arcuate form seen in castanea and hrevihastata. 

 It is evident that there is considerable individual variation in the 

 depth of the ovipositor, this being very apparent in those species 

 represented by considerable series, so much so that the extremes have 

 different facies, but the major portions of such series always bridge 

 the apparent gaps. In ovipositor length there is marked variation 

 in gladiator and hrevihastata, this being most apparent in the former 

 species, the extremes of which are quite different in appearance. 

 We have before us ten female nymphs which we can positively refer 

 to five species {durangensis, hrevihastata, gladiator, oreoeca, and j)olli- 

 cifera). Of durangensis we have represented the second instar 

 preceding maturity, of hrevihastata the two preceding maturity, and 

 of the other three species the instar preceding maturity. From this 

 material it is evident that the development of the ovipositor is very 

 rapid, but in no case do the external margins acquire distal teeth until 

 the mature condition is reached. In one specimen which is appar- 

 ently on the eve of the last ecdysis (the type of Icevis) the teeth of 

 the enclosed ovipositor can be seen through the sheath when it is 

 held to the light. 



The subgenital plate of the female presents great diversity in 



