278 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



of Chisos Mountains, Texas: April 20, 

 19.^9, J. A. & H. H. Ross. 



Allotype, female. — Same data as for 

 holotype. 



Paratype. — Same data as for holotype, 

 16. 



Neotrichia osmena new species 



This species belongs with certain Mexican 

 species of the subgenus Exitrichia, especially 

 digitata Mosely and eroga Mosely. From 

 the former, osmena differs in the curved and 

 spatulate lateral processes of the ninth seg- 

 ment, and from the latter in the shorter, 

 black claspers. 



Male. — Length 2.2 mm. Color dark 

 brown. General structure, including wing 

 venation, spur count, and other characters 

 of head and thorax, identical with other 

 described members of the genus. 



Fig. 928. — Neotrichia osmena, male geni- 

 talia. A, lateral aspect; 5, dorsal aspect; C, 

 ventral aspect; D, aedeagus. 



Genitalia as in fig. 928. Ninth segment 

 with invaginated portion triangular, dorsum 

 covered with sparse short setae. Tenth ter- 

 gite blunt, the medium portion of its apex 

 produced into a rounded lobe from the 

 base of which arise a pair of long spines. 

 From beneath this structure arise a pair 

 of large, heavily sclerotized, blunt struc- 

 tures which appear slightly forceps-like from 

 dorsal view. From an incision on the lateral 

 margin of the ninth segment arises a cercus- 

 like flap which is expanded at apex, is 

 clothed with a scattering of long setae, and 

 is concave on the mesal face. Claspers black, 

 with a broad base that tapers more or less 

 regularly to the apex, and with a dorsal 

 hook which reaches two-thirds of the dis- 

 tance to the apex. Aedeagus with a wide 

 tubular base which constricts rapidly to a 

 long narrow neck; from the apex of the 

 neck arises a spiral process which encircles 

 the tube slightly more than once; the apex 

 is fairly evenly cylindrical, with the apex in- 

 cised. 



Holotype, male. — Blacksmith Fork Can- 

 yon, Utah: Sept. 16, 1938, at light, Knowl- 

 ton. 



May atrichia Mosely 



(See also p. 160) 



KEY TO SPECIES 

 Males 



1. Aedeagus ending in a small, scle- 



rotized three-pronged structure; 

 claspers each with about 6 setae on 



mesal lobe, fig. 929 ayama Mosely 



Aedeagus ending in a simple point, 

 usually only lightly sclerotized; 

 claspers each with 3 setae on mesal 

 lobe, figs. 930, 931 2 



2. Claspers with mesal lobe nearly trun- 



cate, the apical setae very long and 



stout, fig. 930 ponta n. sp. 



Claspers with mesal lobe oblique, each 

 apical seta situated much lower 

 than the one above, and all 3 short 

 and slender, fig. 931 acuna n. sp. 



Mayatrichia ponta new species 



This species is most closely related to the 

 Mexican rualda Mosely, from which it 

 differs in having three instead of two large 

 setae on each clasper and in shape of other 

 sclerites of the genital capsule. 



