124 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Ithytrichia clavata Morton 



Ithytrichia clavata Morton (1905, p. 67); d^. 



Larva. — What is possibly the larva of 

 this species was illustrated by Needham 

 (1902, p. 377, figs. 2-5). His drawing is 

 reproduced here in fig. 456. No additional 

 material of this form has been found. 



Fig. 459. — Ithytrichia clavata, female geni- 

 talia. A, ventral aspect; B, bursa copulatrix. 



Adults. — Length 3 mm. Color dark 

 brown with light mottling over body and 

 wings. Male genitalia, fig. 457: ninth and 

 tenth tergites entirely membranous dorsally, 

 the lateral portion extending to apex of 

 clasper and forming an apical portion with 

 downcurved, truncate lateral aspect and a 

 flared ventral aspect; below this is a thumb- 

 like protuberance from which arises a fin- 

 ger-like process; claspers long and slender, 

 tapering to a narrow apex; aedeagus long, 

 with tubular base, distinct neck with a stout 

 spiral process and long apex flattened and 

 flanged at end. Female genitalia, fig. 459: 

 eighth sternite membranous with six setae 

 at apex, each on a separate basal tubercle; 

 near middle of segment is a curious, head- 

 like structure having internal lobes connect- 

 ed with its base; bursa copulatrix with base 

 open, fig. 4595. 



Allotype, female. — Cultus Lake, Sardis, 

 British Columbia: July 23, 1936, H. H. 

 Ross. 



Our only Illinois collection of this species 

 was made at light, along the Galena River, 

 . Council Hill, June 26, 1940, Mohr & Riegel, 

 7 $ . We have female specimens from Mun- 

 cie which may be this species. Since the 

 female of mazon is not known and may be 

 similar to that of clavata, it seems best to 

 leave these Muncie specimens unidentified. 



The species has a very wide range, at 

 least transcontinental and perhaps Holarctic, 



with records from British Columbia, Cali- 

 fornia, Illinois, New York, Oklahoma, 

 Pennsylvania. Tjeder (1930) records the 

 species from Sweden, but there is a doubt 

 as to the correctness of his identification. 



Ithytrichia mazon new species 



Male. — Length 3 mm. Color brown with 

 light mottling over body and wings. Gen- 

 eral structure typical for genus. Male 

 genitalia, fig. 458: ninth and tenth tergites 

 not separated, both membranous; lateral 

 area of ninth segment sinuate at base, with 

 an arcuate, sclerotized dorsal thickening, 

 the apex wide and without flared areas or 

 processes; claspers nearly straight, ventral 

 aspect parallel sided and truncate at apex; 

 aedeagus with long, tubular base, round 

 neck, and with spiral and apex similar to, but 

 slightly narrower than, those in fig. 457C 



Holotype, male. — Mazon, Illinois, along 

 Mazon Creek, June 16, 1938, B. D. Burks. 



Known only from the holotype. This 

 species resembles lamellaris Eaton most 

 closely but differs in having no sclerotized 

 dorsal rods beneath the base of the ninth 

 tergite and in the truncate apex of the 

 claspers. The type was collected at light 

 along the banks of Mazon Creek, which is 

 a small stream laden with pollution. 



Tascobia new genus 



Larva (mature type). — Head rounded, 

 all legs short and stocky. Abdomen grad- 

 ually enlarged toward middle, tapering to 

 posterior end, with moderate constrictions 

 between segments. Anal hooks short and 

 not projecting on "legs." 



Case. — Purselike, of fibrous construction. 



Adults. — Length 3 mm. Color salt-and- 

 pepper mottling. Ocelli present, lateral pair 

 close to eye. Wings only moderately nar- 

 rowed at apex. Legs with spur count of 

 1-3-4. Notum, fig. 438, with mesoscutel- 

 lum divided by transverse line; metascutel- 

 lum wide, short and rectangular. \ 



Genotype. — Stactobia palmata. 



This genus includes palmata, brustia and 

 delira, all placed previously in the genus 

 Stactobia. Stactobia is apparently restricted 

 to Europe and is quite distinct from this 

 new genus as evidenced by differences in 

 larvae and genitalia. Characters to sepa- 

 rate Tascobia from other Nearctic Hydrop- 

 tilidae are given in the key to genera. 



