130 U.S. NATIONAL MUSEUM BULLETIN 244 



with 1-2 minute apical spurs. Hindlegs most reduced, femur sub- 

 globose, tarsal segments very short, compact. Abdomen exceeding 

 hindmargin of secondaries by usually half its length. 



Wings mostly transparent, nearly devoid of scales in flown speci- 

 mens, some scaling concentrated in anal area of hindwing, less in that 

 of forewing; venation (fig. 168) extremely variable, at least in Thyri- 

 dopteryx ephemeraefonnis. Primaries elongate, usually 11 -veined; R3 

 and 4 almost always long stalked; M2 and 3 usually completely fused in 

 both wings, frequently separating near margin; Mi widely separate 

 from M2+3; base of M divided withui cell of both wings; lA curving 

 abruptly down to connect with 2A, with often a short spur toward 

 outer margin; 2A and 3A separate near wing base, then joining and 

 mmiediately separating, with 2 A continuing to outer margin, 3 A a short 

 spur directed toward hindmargin. Secondaries ovoid-triangulate, 

 approximately ji area of primaries, outer margin more or less evenly 

 rounded; frequently 7-veined, often 6 veins, depending on fused or 

 separate condition of Sc+Ri aud Rs at apex of wing; Sc frequently 

 with 1-2 spurs arising near an oblique crossvein usually present mid- 

 way along cell between Sc+Ri and Rs; Rs converging with Sc+Ri be- 

 yond apex of cell, usually separating again, sometimes remaining fused 

 to margin; lA completely atrophied or with faint vestige curving 

 abruptly downward into 2A somewhat as in forewing, 



Male genitalia. — Elongate. Apex of tegumen with shallow cleft. 

 Valves mth pulvilli moderately to well developed, partially covered 

 with spinules; apex of sacculus minutely spined. Vinculum long, 

 narrow, gradually tapering to elongate saccus. Base of aedeagus 

 prominently expanded. 



Eighth sternite with f ureal arms well developed, more or less parallel; 

 base relatively robust, nearly truncate at posterior margin. 



Female. — Vermiform. All body appendages vestigial, reduced to 

 tiny tubercules or completely absent. Dorsum of head, thorax lightly 

 sclerotized; remainder of body membranous, whitish. Posterior end 

 of abdomen with complete circle of dark, woolly hair. 



Female genitalia. — (Fig. 316.) External genitalia largely mem- 

 branous, single pair of short rodlike apodemes extending from about 

 level of ostium into terminal segment (9-flO); dorsum of eighth 

 abdominal segment with two broad, symmetrical pairs of apodemes 

 along anterior margin, which taper forward into seventh segment. 

 Internal genitalia with extremely long, convoluted ductus seminalis; 

 bursa large, several times volume of spermatheca; spermatheca as in 

 other psychids examined; accessory glands arising posterior to vestib- 

 ulum, branched. 



Discussion. — In 1865 Grote described a new genus and species 

 of psychid from Cuba, Hymenopsyche thoracicum. He correctly 



