78 COXNECTICUT GEOL, AND NAT, HIST. SURVEY [BlllL 



steniite is called the hypogynium. The valves of the eighth sternite 

 are called hvpovalvae or hypogynial valves in female Tipulidae. 



The ninth abdominal segment which bears the male genitalia is 

 called the genital segment, or andrium, in male insects. The ninth 

 tergite is then referred to as the epandrium and the ninth sternite is 

 caUed the hypandrium in these insects. AVhen the ninth segment is 

 called the aiidrium, the segmental complex preceding it may be re- 

 ferred to as the protandrium in the males of the Cyclorrhapha 

 (Sarcoi)hagidae, etc.), in which this structure is closely associated 

 with the ninth segment. The students of these Diptera usually refer 

 to the protandrium and andrium as the first and second genital seg- 

 ments; and these parts are also referred to as the pregenital and 

 genital segments by some dipterists, but the so-called first genital 

 "segment" or pregenital "segment" is not a segment at all, but is 

 a synsternite, or composite sclerite made up of the united seventh 

 and' eighth sternites Avhich have become displaced into the dorsal 

 region. It is therefore preferable to refer to the synsternite and 

 ninth segment as the protandrium and andrium. Furthermore, the 

 designation pregenital segments is frequently applied to all of the 

 abdominal segments anterior to the ninth or genital segment proper 

 (or the segments called the visceral segments by Snodgrass, 1935), 

 and tliis usage is an extremely useful one. In the lower Diptera the 

 ninth or genital segment not only bears an aedeagus, or male organ 

 proper, but also bears the two-segmented genital forceps, or forcipate 

 parameres, homologous with the forcipate parameres of male Trichop- 

 tera, Mecoptera, Hymenoptera, etc. ; and in the higher Diptera the 

 ninth segment also bears the aedeagus and the paired so-called anter- 

 ior and posterior gonapophyses (which may be peculiar to these 

 Cyclorrhapha). 



The Postgenital Segments. The designation posfcgenital seg- 

 ments refers to the segments behind the genital segments, and is usual- 

 ly applied to the segments behind the eighth abdominal segment of 

 the female (when the ninth does not bear any processes, etc.) and 

 those behind the ninth abdominal segment in the male. The post- 

 genital segments are best developed in female Tipulidae, and are 

 fairly well developed in the females of some of the higher Diptera 

 (Fig. 9, F) ; but in most male Diptera they are reduced and fuse to 

 form the small inconspicuous so-called "anal segment" or proctiger, 

 borne behind the ninth abdominal segment. 



The reduction and fusion of the postgenital segments to form a 

 proctiger or composite "anal segment", pgr^ is more extensive in the 

 females of the higher Diptera shown in Fig. 9a, B, C and D, than, in 

 the corresponding males (i. e., pgr of Fig. 13, D, E and F, or Fig. 14, D, 

 F and H, etc.), since the greater importance of the ninth segment as 

 the functional genital segment of the male would prevent its re- 

 duction and incorporation into the proctiger in the higher Diptera, 

 in which this consideration does not apply in the case of the female, 

 since the eighth is the functional genital segment of the female, and 



