SPONGILLA-FLIES — PARFIN AND GURNEY 453 



gradates in the hindwing when they occur. The coupling apparatus 

 consists of a convex jugal lobe on the forewing and a poorly developed 

 humeral lobe bearing two bristles on the hindwing. In general, the 

 costal cross-veins tend to be closer together toward the base of the 

 wing. 



A question which has arisen all through this investigation has been 

 whether Sc and Rl are actually fused or coalesced distally before the 

 pterostigma in all genera of the family. The original diagnoses of the 

 family, as given by Handlhsch (1906, pp. 40-42; 1908, pp. 1251, 1292) 

 do not mention the fusion as a characteristic of the family, although 

 Tillyard (1916, p. 312; 1926, p. 316), Comstock (1918, p. 177), and 

 Carpenter (1940, pp. 194, 253) state that the fusion does take place. 

 Ki'iiger (1923) has noted a difference in this point in regard to the 

 ! different genera. In the present study of the wings of the four genera 

 (Sisyra, Climacia, Neurorthus, Sisyrina) there did appear to be a 

 I definite fusion in Climacia, but in Sisyra and particularly Neurorthus 

 there was some doubt (e. g., in a single specimen of Sisyra, one wing 



; might appear to show Sc and III fused, but the other might show them 

 running free to the margin; or in certain species, as panama, Sc appears 



I weak at the margin). In Neurorthus, Sc gives the appearance of 

 being free at the apex and joined to Rl by a short subcostal cross-vein. 



I In the specimen of Sisyrina examined, Sc seemed to atrophy at the 

 apex. The terminal fork of Rl at the end of the pterostigma is weak, 



I as are also the pterostigmal cross-veins in all genera. 



Abdomen (fig. 12): 10-segmented; a pair of spiracles on each of 

 first eight segments, the first pair the largest, closest to anterior 

 margin, the other pairs smaller, located less anteriorly; first segment 



I short, sternite and tergite reduced, only small sclerotized lateral 

 pieces, rest membranous; second and third tergites usually small, 



i second and third sternites usually larger than fourth to seventh tergites 



: in the female and to eighth in the male, which are more uniform; 

 transverse streaks ("secondary sutures" of Killington, 1936, p. 36) 



I or sulci (for strengthening) present on second and thhd sternites, 

 sometimes on fourth to sixth sternites, varying in stage of develop- 



I ment, usually becoming shorter and weaker more distally, on second 

 segment cm-ved toward anterior margin. 



Genital segments of male varying considerably in shape and size 

 in different genera; ninth tergite divided or greatly weakened mid- 

 dorsaUy, sometimes moved lateroventrally to tenth tergite and much 

 smaller and more difficult to see (Sisyra), almost fused with it (S. 

 minuta), larger and almost as broad as tenth tergite {Climacia)', 

 ninth sternite located below ninth tergite, ventrally more or less 

 convex, and with a pair of internal distally projecting processes 

 {Climacia), or larger, more like eighth sternite {Sisyra); tenth tergite 



359326 — 56 5 



