August, 1944 



Ross: Caddis Flies of Illinois 



271 



Hydropsyche solex new species 



This is most closely related to calif orn'ua, 

 differing from it in the extremely constrict- 

 ed aedeagus. In this regard it approaches 

 delrio, but delrio is readily distinguished by 

 the short, apical segment of the clasper and 

 the mesal cavity of the aedeagus, which is 

 almost entirely closed. 



Male. — Length 11 mm. Head and body 

 black; antennae very slender and yellowish, 

 with dorsal black V-marks on the first eight 



Fig. 913. — Hydropsyche solex, aedeagus. A, 

 lateral aspect; B, ventral aspect. 



segments of the flagellum; eyes red, legs 

 yellowish brown, the femora darker; front 

 wings tawny brown, irrorate, with abundant 

 fenestrate cream-colored marks. General 

 structure typical for genus. Male genitalia 

 in general typical for the scalaris group. 

 Ninth segment only slightly humped dorsad. 

 Tenth tergite somewhat hood shaped, with 

 a fairly wide mesal incision and with each 

 lateral lobe produced into a very small 

 point. Claspers slightly sinuate; apical seg- 

 ment nearly one-half as long as basal seg- 

 ment, the apex obliquely truncate. Aedea- 

 gus, fig. 913, with the base round, the stem 

 constricted to a narrow central portion and 

 greatly expanded at apex ; apical portion 

 definitely narrowed from stem, heavily scle- 

 rotized and almost black; mesal cavity al- 

 most entirely open; mesal plates small; 



Fig. 914. — Hydropsyche solex, female geni- 

 talia. A, lateral aspect; B, dorsal aspect. 



lateral plates wide, from lateral view hiding 

 the meso-dorsal portion. 



Female. — Length 13 mm. In color and 

 general structure similar to male. Ninth 

 tergite, fig. 914, with clasper groove large, 

 invaginated only slightly under dorsal cap. 

 from dorsal view appearing to extend deeply 

 beneath cap; lateral lobe large, with abun- 

 dant setae; postero-lateral flange well de- 

 veloped. 



Holotype, male. — Balmorhea, Texas, 

 along stone irrigation flume: April 19, 1939, 

 H. H. & J. A. Ross. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — Same data as for holotype, 

 U , 3 9 . 



Leucotrichia Mosely 



(See also p. 120) 



KEY TO MALES OF NEARCTIC 

 SPECIES 



1. Ninth segment with a pair of long, 



sclerotized spurs and long styles, 



fig. 915 notosa n. sp. 



Ninth segment without long, project- 

 ing spurs and styles, fig. 916 2 



2. Eighth sternite with lateral margin 



forming long, triangular lobes, fig. 



917 sarita n. sp. 



Eighth sternite without lateral lobes 

 but with a pair of pointed lobes 

 situated ventrad, figs. 916, 918. ... 3 



3. Seventh sternite with an apico-mesal, 



short process; aedeagus with a long, 

 dorsal loop extending over its base, 



fig. 918 limpia n. sp. 



Seventh sternite with no short process 

 but instead with an apico-mesal 

 brush of dark setae; aedeagus with 

 a pair of short, dorsal processes not 



produced into a loop, fig. 916 



pictipes (Banks) 



Leucotrichia notosa new species 



The long, lateral styles of the ninth seg- 

 ment distinguish this species from all others 

 in the genus, as pointed out in the preceding 

 key. 



Male. — Length 4 mm. Color mottled 

 light and dark shades of gray, the legs con- 

 spicuously banded, essentially similar in this 

 characteristic to pictipes. General structure 

 typical for the genus. Seventh segment with- 

 out a mesal projection. Eighth segment with 

 the tergite reduced to a narrow triangular 



