No. 64] DUTERA OF CONNECTICUT: MORPHOLOGY 77 



recommend it. We already have the desifination terminalia for in- 

 dicating the oenital and postgenital segments, or the postabdomen 

 (when its segments differ from the preceding ones), so that it is not 

 necessary to employ the term hypopygium for the same parts, and it 

 is therefore preferable to restrict the designation hypopyginm to 

 the genital segments, and their ])arts, in both sexes of the Diptera, 

 since this usage is more nearly in accord with the meaning of the 

 word hypopygium. 



The designation "male and female genitalia"' is frequently used as 

 a synonym of "male and female hj'popygium*', but Edwards (1920), 

 in a footnote to page 24, suggests that the designation male genitalia 

 "should perhaps be confined to the chitinizations of the genital tube'", 

 and states that other designations such as male armature and copula- 

 tory apparatus, which have been api^lied to the hypopygium, are 

 unsatisfactory. 



Since there is no specific designation for referring to the parts in 

 question, it is here suggested that the term genitalia be restricted 

 to the parts in the immediate neighborhood of the genital opening 

 of the male or female insect. The term genitalia would then denote 

 the parts of the eighth and ninth sternites lying adjacent to the 

 female genital opening (which is situated between the eighth and 

 ninth sternites) and would also denote the parts adjacent to the 

 male genital opening, namely the aedeagus and the parts on each 

 side of it (such as the genital forceps of the males of the lower 

 Diptera, and the so-called anterior and ])Osterior gonapophyses of 

 male Cyclorrhapha). We nuiy then differentiate the male genitalia 

 into the aedeagus, or male organ proper, and the ancillaries, or struc- 

 tures on each side of it, such as the genital forceps and the gona- 

 pophyses etc.. mentioned above. 



The highh' modified cerci and surstyli of male Cyclorrhapha are 

 so closely associated with the genitalia of these insects that all of 

 these structures might be included in the designation "male arma- 

 ture''. The designation copulatory apparatus, oi- copulatoria, might 

 then be made to include all of these structures, together with the 

 copulatory lobes of the fifth sternite of male Cyclorrhapha, since 

 all of these structures serve as parts of the copulator}^ apparatus in 

 the mating process. If this usage is followed, the designations 

 genitalia, male armature and copulatory apparatus, will have more 

 exact meanings than they do when used as synonyms of hypopygium, 

 terminalia, etc. 



The Genital Segmeiit.s. The female gonopore, or the opening 

 of the common oviduct, or the opening of the cavity into Avhich it 

 discharges, is located between the eighth and ninth abdominal ster- 

 nites (or just behind the eighth sternite) but much of the cavity is 

 contained in the eighth segment, which is therefore called the true 

 genital segment (or gynium) of the female, although the ninth ab- 

 dominal segment may also contain genital parts adjacent to tlie female 

 gonopore. When the eighth abdominal segment of the female is called 

 the gynium, its tergite is referred to as the epigyniuiii and its 



