138 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 1 



Male genitalia, fig. 487: eighth segment 

 spiny at sides; claspers projecting and up- 

 turned at apex; aedeagus with a long, rib- 

 bon-like spiral and with apex knobbed and 

 bearing a pair of sharp, short processes. 



Our only records of this species in Illi- 

 nois have been taken along the Kankakee 

 River at Momence during May. Nothing 

 is known regarding its biology. 



Records of this species are very scattered 

 but indicate an extensive range stretching 

 from New York to Oklahoma, with records 

 available for Indiana, New York and Okla- 

 homa as well as Illinois. 



Illinois Records. — Momence, Kankakee 

 River: May 17, 1937, Ross & Burks, 1 $ ; 

 May 24, 1937, H. H. Ross, U. 



Oxyethira novasota new species 



Male. — Length 3 mm. In color and gen- 

 eral structure similar to the preceding, the 

 diagnostic characters apparently confined to 

 the male genitalia. 



Genitalia as in fig. 489. Eighth segment 

 very simple, without sclerotized processes, 

 both dorsal and ventral margins of the apex 

 circularly incised, the dorsal incision bear- 

 ing membranous folds; there is a distinct 

 angle where the dorsal margin and the lat- 

 eral margin join. Ninth segment short; the 

 venter with a wide, triangular emargination, 

 the dorsum reduced to a narrow bridge. 

 Tenth tergite somewhat inverted U-shaped, 

 the base large and the apex pointed; the 

 basal portion is bridgelike and the apex is 

 divided into a pair of lobes appearing some- 

 what triangular, as viewed from above, and 

 pointed mesad, not quite touching at apex, 

 and armed at tip with a minute spine. Be- 

 low the tenth tergite is a pair of semimem- 

 branous horns, each surmounted by a long 

 seta. Below this are two plates, a short 

 wide one with a slightly concave posterior 

 margin and below that a longer one divided 

 into a pair of rounded lobes separated by a 

 rounded mesal incision, the ventral margin 

 armed with a cluster of long setae. Aedea- 

 gus with a wide, tapered, tubelike basal por- 

 tion; a sinuate, wide "neck" from which 

 arises a long, stout spiral encircling the 

 structure one and one-half times, proceeding 

 as far toward the posterior as the remain- 

 ing genitalia and ending in a clavate tip; 

 and an apical tube which tapers from the 

 base to the middle, then expands slightly, 

 and is divided at the extreme apex into a 

 sclerotized point and a semisclerotized lobe 



which appears beaked from lateral view and 

 ovate from dorsal view. 



Female. — Length 3.2 mm. Color and 

 general structure as for male. Genitalia 

 as in fig. 497. Eighth segment with tergite 

 simple, bearing at apex an irregular row 

 of long setae. Eighth sternite with its apical 

 margin produced into a long, rounded pro- 

 jection which merges with the ninth sternite. 

 Ninth tergite fairly heavily sclerotized, its 

 baso-ventral angle produced into a long, in- 

 ternal rod, its baso-dorsal region produced 

 into a rounded projection bearing a cushion 

 of short, thick, black spines and its apex 

 tapering to meet the tenth tergite. Tenth 

 tergite appearing narrow from lateral view 

 and wide and emarginate from ventral view 

 with a pair of styles arising from each later- 

 al hump. From the inner margin of the 

 apex of the eighth arises a series of semi- 

 membranous folds \vhich encircle the bursa 

 copulatrix. This structure is irregular in 

 shape, somewhat like a truncate cylinder, 

 the posterior margin with a wide opening 

 around the ventral margin from which arises 

 a group of semisclerotized, irregular, tooth- 

 like lobes. 



Holotype, male. — Marquez, Texas, 

 along Novasota River: April 16, 1939, J. A. 

 & H. H. Ross. 



Allotype, female. — Same data as for 

 holotype. 



Paratypes. — Texas. — Same data as for 

 holotype, 1 $ . 



On the basis of genitalia, this species is 

 most closely related to grisea from which it 

 differs in the two-lobed apex of the aedeagus 

 and other characters of the genitalia. 



This species has not yet been taken in 

 Illinois. The river along which it was col- 

 lected in Texas is a sluggish, silty river 

 much like some of the rivers of southern 

 Illinois, and there is a good possibility that 

 it may be found in Illinois with additional 

 collecting. 



Oxyethira grisea Betten 



Oxyethira grisea Betten (1934, p. 162); cT. 



Adults. — Length 3 mm. Color a salt- 

 and-pepper mottling of cream and brown. 

 Male genitalia, fig. 488, similar in general 

 features to those of the preceding species, 

 differing chiefly in the apex of the aedeagus 

 and smaller cleft of the fused claspers. 



The holotype of this species may be lost. 

 There seems little doubt, however, that our 



