No. 64] DIPTERA or CONNECTICUT: MORPHOLOGY 107 



Diptera may possibly be represented b}^ the structure which Awati 

 calls the "vesiculum" (a misprint for vinculum?). Edwards (1920) 

 suggests as an alternative view, that the ninth sternite of the higher 

 Diptera may be represented by the structures called the "edita" by 

 Newstead (1911) in Glossina (i. e., the surstvli labelled ss in Fig. 

 13, E). Hewitt (1914) and Berlese (1909) also consider that the 

 surstjdi of the housefly (i. e., the structures labelled ss in Fig. 13, F) 

 represent the halves of the "genital sternite", but the structures in 

 question are appendages of the ninth tergite homologous with the 

 surstyli of lower insects. In a footnote to page 49, Hendel (1928) 

 makes the further suggestion that the anterior gonapophyses, ago^ of 

 Fig. 13, E, represent the "ninth sternite", while the posterior gon- 

 apophyses, pgo, may represent the "tenth sternite" in the higher Dip- 

 tera. 



The ninth sternite or hypandrium, labelled 9s in Fig. 14, E, of a 

 typical muscoid fly, is a flat Y-shaped plate embedded in the dorsal 

 wall of the membranous genital pouch or cubiculum, phc^ of Fig. 14, F, 

 just in front of the base of the male genital organ labelled pho in 

 Fig. 10, E, or Fig. 14, E, etc. The flat anterior portion, or "stem" of 

 the Y-shaped plate, projects forward and upward from the lower 

 angles of the ninth tergite, 9^; and a plicate fold at its anterior end 

 projects internally to form an apocleme-like projection labelled Jia 

 in Fig. 10, E, Fig. 14, E, or Fig. 14, F, Fig. 9a, A, etc., Avhich may 

 be called the hypandrial apodeme. 



The posterior arms of the Y-shaped ninth sternite, 95, extend 

 backward on each side of the base of the male genital organ, j^ho, of 

 Fig. 14, E, or Fig. 10, E, etc., and are connected with the bases of the 

 surstyli, ss, by connecting rods in the form of bacilliform sclerites, 

 hcs, lying just below the lateral margins of the ninth tergite. 9;^. These 

 connecting rods probably aid in flexing the surstyli, ss. of Fig. 14, E, 

 (and the cerci, ce, Avhich are closely associated with the surstyli) when 

 the Y-shaped sclerite, 9s, is drawn forward. Patton (1932-1935) re- 

 fers to these connecting rods as the basal segments of the "coxites" 

 (i. e., the basal segments of the surstyli, ss, which he regards as the 

 homologues of the "coxites" or basimeres), but the connecting rods 

 are probably merely secondarily-developed sclerites which do not 

 occur in all of the higher Diptera. It is possible that the vestigial 

 sclerites which Patton (1934) regards as the "sclerotized spiracles" 

 of the eighth segment in the Sarcophagidae may represent the re- 

 mains of such connecting rods in these insects. At any rate, they do 

 not represent the "sclerotized spiracles" of the eighth segment, since 

 the eighth abdominal spiracles are always absent in male Diptera. 



On each side of the base of the male genital organ, jjha, of such 

 muscoid flies as Phormla (Fig. 13, E), Hylemyia (Fig. 13, D), etc., 

 is a pair of sclerites, ago and pgo, called the anterior and posterior 

 gonapophyses by Lowne (1895) in the male blowfly. The gonapophy- 

 ses are also referred to as the parameres by Bruel (1897) and Patton 

 (1932), and by Hendel (1928), who refers to the anterior gonapopliy- 

 ses as the distal gonapophyses (or parameres) and designates the 



