August, 1944 



Ross: Caddis Flies of Illinois 



277 



separated by a high membranous fold. From 

 below the base of the tenth tergite arise 

 a pair of long, membranous filaments which 

 continue beneath the full length of the ter- 

 gite and then curve sharply dorsad around 

 its tip; just before the turn these processes 

 have a large, sharp lateral spur. Claspers 

 with a small, triangular base and a long, 

 slightly spatulate blade irregularly set with 

 setae, the two blades close together at base 

 and diverging slightly toward apex; lateral 

 aspect curved and slightly arcuate. Aedea- 

 gus almost exactly as for vala (see fig. 515), 

 having a long narrow neck, long stout spiral, 

 the apical portion long, cylindrical and 

 sharply angled at tip. 



Female. — In size, color and general stuc- 

 ture similar to male. Genitalia apparently 

 identical with those of vala; eighth sternite 

 with a central Y-shaped plate, the apex with 

 an arcuate lobe bearing six long setae (see 

 fig. 530). 



Holotype, male. — Lake Waskesieu, 

 Prince Albert National Park, Saskatche- 

 wan: Aug. 15, 1940, L. T., No. 8, Don 

 Milne. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — Same data as for holotype. 

 U, 19. 



Neotrichia sonora new species 



This species is most closely related to 

 okopa, but may be separated from it by the 

 slender and upturned apex of the claspers, 

 in addition to the different conformation of 

 the tenth tergite. 



Male. — Length 2.25 mm. Color of body 

 and appendages a uniform light shade of 

 brown. General structure typical of the 

 subgenus Exitrichia. 



Genitalia as in fig. 927. Ninth segment 

 annular, the invaginated basal portion short 

 and subtriangular, the dorsum covered with 

 a scattering of very short setae; the apical 

 margin of the dorsum appears to be pro- 

 duced into a somewhat irregular, membra- 

 nous hood covering the tenth tergite. Tenth 

 tergite pointed at apex, seen from above, 

 produced into a rounded mesal lobe from 

 the base of which arise a pair of long setae. 

 From the sides of this structure arise a 

 pair of heavily sclerotized, long points 

 curved slightly ventrad, and below these a 

 pair of heavily sclerotized, triangular bodies. 

 From the lateral margin of the ninth arise 



a pair of cercus-like appendages which are 

 slightly enlarged toward apex, clothed with 

 a scattering of long setae and concave on 

 the mesal face. Claspers very heavily scle- 

 rotized and black, seen from lateral view; 

 thick at base, tapering to a fiat and slightly 

 upturned apical portion; somewhat rectan- 

 gular from ventral view but with irregular 

 margins and with apex triangular; mesal 

 margin bearing a pair of small toothlike 

 projections below apex, and below these 

 there arises a stylelike appendage from the 

 mesal face. Aedeagus practically identical 

 with that of okopa except that the spiracle 

 extends closer to the apex. 



Female. — Size, color and general struc- 

 ture as for male. Genitalia, including orna- 

 mentation and coloration of eighth sternite 

 and bursa copulatrix, apparently identical 

 with those of okopa. 



Holotype, male. — Neville Spring at foot 



Fig. 927. — Neotrichia sonora, male genitalia. 

 A, lateral aspect; B, dorsal aspect; C, ventral 

 aspect. 



