1914.] NATURAL SCIENCES OF PHILADELPHIA. 149 



the type, while in the others the head of the process is more 

 or less expanded with the distal margin arcuate. The anomalous 

 cerci seem to vary little or not at all, while the subgenital plate varies 

 only in that the quadrate emargination of the distal margin is re- 

 placed by a V-shaped emargination in one paratj-pe. The female 

 shows variation chief!}' in the robustness of the ovipositor, although 

 this is not as pronounced as in some other species of the genus. 



Remarks. — The structure of the apex of the abdomen in the male 

 of this species and the very heav>' ovipositor of the female are char- 

 acters which serve to easily distinguish the present peculiar form. 

 There is no approach to the genital structure of the male in any of 

 the other forms of the genus, except that th» tooth springs from the 

 external margin of the shaft of the cercus in this and in poUicifera, 

 which similarity is somewhat augmented by the general form of the 

 pronotum and tegmina, but there the analog}' ceases, as the details of 

 the abdominal appendages and of the tegmina are quite different. 

 The female sex, however, shows no close affinity to poUicifera, while it 

 does have much in common with falcata, to which the male sex shows 

 no affinity. 



Specimens Examined. — 12; 4 males, 8 females.. 



Mountains twelve leagues east of San Luis Potosi, Mexico, 

 (Palmer), 2 cf, 4 9. Type, allotj-pe, and paratj'pes. [Scudder 

 Collection.] 



Sierra de San IMiguelito, state of San Luis Potosi, ^Mexico, (Palmer), 

 2 cf , 3 9 . Paratypes. [Scudder Collection.] 



Mountains at Alvarez, state of San Luis Potosi, ^lexico, (Palmer), 

 1 9 . Paratype. [Scudder Collection.] 



Dichopetala tridactyla n. sp. 



This species can be immediately separated in the male sex from all 

 of the species of the genus, except D. caudelli, by the peculiar appen- 

 chculate character of the cercus, while from caudelli it can be separated 

 in the male sex by the shorter tegmina, the verj^ brief distal portion 

 of the anal. field of the same, by the sutural margin of the tegmina 

 being strongly produced at the apex of the stridulating vein and by 

 the more elongate median tooth of the cercus. In the female sex 

 tridactyla can be separated from caudelli by the shorter ovipositor 

 and blunter apices to the lobes of the subgenital plate. 



Type: cf" ; -Camacho, Zacatecas, ^Mexico. November, 1877. (Law- 

 rence Bruner.) [Hebard Collection.] 



Description of Type. — Size small. Head with the occiput well 



