August, 1944 



Ross: Caddis Flies of Illinois 



269 



almost truncate and having a scattering of 

 medium length setae ; apical segment short 

 and boot shaped, the dorsal heel small and 

 pointed, the ventral toe large and somewhat 

 triangular, with a brush of short setae on 



Fig. 909. — Rhyacophila harmstoni, male 

 genitalia, ji, lateral aspect; B, tenth tergite; 

 C and D aedeagus, respectively lateral and 

 ventral aspects. 



the inner margin at apex. Aedeagus with 

 dorsal portion very narrow, ventral portion 

 expanded and wider; armature consisting of 

 a mesal style which is widest at base and 

 tapers rather rapidly to a slender straight 

 apex, flanked on each side by a curved 

 cluster of three or four spines fused on 

 basal portion and sinuate at apex. 



Holotype, male. — Strawberry Valley, 

 Utah: July 15, 1938, Knowlton & Harm- 

 ston. 



A gapetus iridis new species 



This species is most closely related to 

 pinatus, differing from it in the truncate 

 lateral aspect of the claspers and the con- 

 formation of the tenth tergite. 



Male. — Length 5 mm. Color dark brown, 

 the legs beyond coxae whitish yellow with 

 black spurs. General structure typical for 

 genus. Genitalia as in fig. 910. Ninth seg- 

 ment cylindrical, its posterior margin trun- 

 cate laterad and incised almost to the base 

 on the dorsum. Cerci long and slender with 

 a dorsal brush of long setae. Tenth tergite 

 very long, the basal part robust, tapering 



Fig. 910. — Agapetiis iridis, male genitalia. 

 Ay lateral aspect; B, tenth tergite; C, clasper. 



to apex ; almost completely membranous 

 except for a pair of stout sharp dorsal spines 

 at apex and a pair of ventral sclerotized 

 ribbons which are expanded and flat at apex 

 and bearing on the lateral corner a fairly 

 long, sharp spine. Claspers long, lateral 

 aspect forming an elongate rectangle, the 

 apico-ventral corner slightly pointed; mesal 

 face with an apical and dorsal sclerotized 

 tooth and with the ventro-mesal margin pro- 

 duced near middle into a wide, triangular 

 lobe sclerotized at apex and evenly curved 

 to meet the slightly wider base. Aedeagus 

 semimembranous and tubular, typical for 

 the genus. 



Female. — In size, color and general 

 structure similar to male. Eighth segment 

 bilaterally compressed, its apical margin 

 slightly incised on meson and with the dorsal 

 margin slightly shorter than the ventral one. 



Holotype, male. — Small creek near Ta- 

 hawus, New York, Adirondack State Park: 

 June 20, 1941, Frison & Ross. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — New York. — Same data as 

 for holotype, 1 $ . Cedar River near In- 

 dian Lake, Tune 20, 1941, Frison & Ross, 



u. 



Chimarra elia new species 



This species is most closely related to 

 utahensis, differing from it in the large, 

 keel-like apical process of the ninth sternite, 

 in addition to other differences in the geni- 

 talia. 



