August, 1944 



Ross: Caddis Flies of Illinois 



149 



tenth tergite pointed and conical; claspers 

 short and sinuate; near base of each clasper 

 arises a short style tipped with a long seta, 

 P ; aedeagus with long, slender spiral and a 

 sickle-like hook at tip. Female genitalia, 

 fig. 532: eighth segment cylindrical, almost 

 membranous, without ventral ornament; its 

 apical margin straight, the ventral margin 

 bearing six evenly spaced setae, each situated 

 on an individual stalk; bursa copulatrix with 

 end short and robust. Tenth segment tri- 

 angular, unique in the genus. 



In Illinois this species is restricted to the 

 Ozark Hills where it has been collected 

 along the streams peculiar to that region 

 (see p. 6). The seasonal appearance of the 

 adults is distinctly vernal, as indicated by 

 records not only for Illinois but for all other 

 states from which the species is known. Al- 

 though the adults have been taken in large 

 numbers, no larvae have yet been discov- 

 ered. 



The known distribution records are 

 scanty, including only Arkansas, Illinois and 

 Oklahoma, but indicate a restriction to the 

 Ozarks and nearby mountains. 



Illinois Records. — Eddyville, Lusk 

 Creek: June 1, 1940, B. D. Burks, 6^, 

 6$. EiCHORN, Hicks Branch: May 29, 

 1935, Ross & Mohr, 1 $ . Herod: May 10, 

 1935, C. O. Mohr, 1 6 ; May 29, 1935, Ross 

 & Mohr, $ $ , 9 5; May 13, 1937, Frison 

 & Ross, $ $ . 



Hydroptila hamata Morton 



Hydroptila hamata Morton (1905, p. 67); c?", 

 9. 



Larva. — Fig. 507. Color variable. Light 

 extreme has head yellow, with black V 

 across top of frons, and pronotum mostly 

 yellow; darker individuals have head with 

 a dusky posterior band and a black pentag- 

 onal central area, and pronotum dark with 

 pale anterior margin. 



Adults. — Fig. 540. Size and color as for 

 armata, except for the femora, which are 

 dark brown or black (they are tawny in 

 other members of the genus). Seventh ster- 

 nite of male with a long mesal process ex- 

 panded at apex and flared laterad, the flared 

 edges serrate. Male genitalia, fig. 512: ninth 

 segment with long, finger-like internal arms; 

 tenth tergite simple; claspers short, with a 

 beaked ventral portion and a finger-like, 

 style-bearing, dorso-lateral portion; aedea- 

 gus very long, the apical portion divided 



into a long, slender filament and a long rod 

 bent sharply at apex. Female genitalia, fig. 

 529: eighth sternite with six apical setae 

 along incised apical margin, and with a pair 

 of transverse sclerotized bands near middle. 

 Although we have collections of this spe- 

 cies from many widely scattered localities 

 in the state, it must be classed as a rarity 



Fig. 540. — Hydroptila hamata d^. 



for Illinois. It occurs in some of our north- 

 eastern glacial lakes and in clear rivers and 

 streams in various other localities, but is 

 almost always collected in very small num- 

 bers. We have associated larvae and adults 

 on the basis of mature pupae from Channel 

 Lake and Lusk Creek. The adults appear 

 from spring to late summer. 



The species ranges throughout most of 

 the mountainous and predominantly hilly 

 country from southern Mexico to at least 

 Washington in the west and to New York 

 and Ontario in the east. It is frequently 

 abundant in such areas as the Ozarks and 

 hilly parts of Oklahoma. Records are avail- 

 able from Arizona, Arkansas, Illinois, Indi- 

 ana, Kentucky, Michigan, Missouri, New 

 Mexico, New York, North Carolina, Okla- 

 homa, Ontario, Oregon, Pennsylvania, Tex- 

 as, Virginia, Washington, Wyoming, Mex- 



ico. 



Illinois Records. — ChannelLake : May 



