August, 1944 



Ross: Caddis Flies of Illinois 



285 



with dorsal portion only slightly flared at 

 apex, ventral portion fusiform, narrow and 

 pointed at apex. 



Holotype, male. — Yosemite National 

 Park, California, along Dana Fork, Tou- 

 lumne River, elevation 8,500 feet: Aug. 15, 

 1935, H. J. Rayner. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — Same data as for holotype, 

 6S. 



Oligophlebodes rtithae new species 



The horizontal claspers place this species 

 in the same group as s'tgma and ardis ; it 

 differs from both of these in the long apex 

 of the claspers and the long and narrow 

 mesal projection of the ninth sternite. The 

 female may be distinguished by the scalloped 

 lateral lobes of the ninth sternite. 



Male. — Length 8 mm. Color mostly 



m^m\m^:fm 



95 1 ^ 



ARDIS "" 



Figs. 948-951. — Oligophlebodes, female geni- 

 talia. 



dark brown, the legs below coxae yellowish 

 and the wings pale brown without conspicu- 

 ous markings. In life the insect appears 

 black with brown wings. General structure 

 typical for genus. Genitalia as in fig. 945. 

 Ninth segment reduced to a linelike collar 

 on the dorsum, expanded into a broad lat- 

 eral portion and a long, tonguelike and 

 angular ventral projection; the lateral mar- 

 gin bears a platelike process which is large 

 and confluent at outer margin with the pos- 

 terior margin of the segment below it. Api- 

 cal blade of clasper long, sharp, sometimes 

 sinuate and with a slightly expanded base. 

 Tenth tergite consisting of indefinite mem- 

 branous folds. Cerci small with abundant, 

 long setae. Aedeagus cylindrical and tubu- 

 lar, with a pair of internal sclerotized rods 

 in addition to the central style. 



Female. — Similar to male in size, color 

 and general structure. Subgenital plate, 

 fig. 948, with a low mesal process and with 

 lateral lobes which are nearly truncate but 

 which have a distinct emargination in the 

 middle of the posterior margin. Bursa copu- 

 latrix with dorsal lobe expanded at extreme 

 tip, ventral lobe fairly wide, scarcely nar- 

 rowed at base but tapering to a long, sharp 

 point at apex. Tenth tergite with lateral 

 lobes sclerotized dorsally. 



Holotype, male. — Roe's Creek, Glacier 

 National Park, Montana: July 12, 1940, 

 H. H. & J. A. Ross. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — Montana: Same data as 

 for holotype, 23(5, 10$; same data but 

 SuNRiFT Creek, 1 $ ; same data but east of 

 Summit, Logan Pass, 1 $ . 



Psilotreta Banks 



Accumulated material in this genus indi- 

 cates that there are five Nearctic species 

 readily separated by characters of the male 

 genitalia. After the discovery of these char- 

 acters I was very fortunate in being able to 

 restudy the Banks and Hagen types in the 

 Museum of Comparative Zoology; in addi- 

 tion, the redescription by Betten & Mosely 

 (1940) of Walker's indecisa has cleared up 

 the identity of that species. It is now possi- 

 ble to place all the names in literature 

 except for dissimilis and borealis. Insuf- 

 ficient material is available to tabulate the 

 females and immature stages. A complete 

 list of synonymy is given in the check list. 



