8-t CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



The Vostalxlomen of Female CydorrMplia. In the female mus- 

 coid flies shown in Fio-. 9, E, and Fio-. 9a, D. the secrments of the 

 postabdonien are extremely slender, and form a telescopic, eo^g-laying: 

 tube (oviscapt or ovicaiida) typical of muscoid flies in general.='^ 

 The tergites of the sixth, seventh and eighth abdominal segments are 

 represented by two slender, longitudinal sclerites, while each of the 

 slender sixtl/and seventh sternites is reduced to a slender median 

 sclerite, and the eiglith sternite is represented by a pair of slender 

 longitudinal sclerit«s, in the female housefly shown in Fig. 9, E, as 

 is also the case in the segments of the postabdomen of the female 

 authomyids described by Huckett (1921-1924). 



The eighth sternite of female muscoid flies does not, as a rule, 

 ])roject posteriorly to form a hypogynium of the type occurring in 

 the orthorrhaphous Brachycera described above, and the ninth seg- 

 ment tends to unite somewhat more closely with the proctiger, or 

 "anal segment", in female Muscoidea. than is the case in the Brachyc- 

 era mentioned above. The cerci of a female housefly are one-seg- 

 mented, lobe-like structures; and in most Cyclorrhapha the cerci 

 appear to be reduced to a single segment. 



In the female calobatid shown in Fig. 10. F, the apparent "seg- 

 ment" behind the sixth is modified to form a strongly sclerotized 

 caudal region, which is broad basally and tapers posteriorly, and is 

 probably used in oviposition. In the trupaneid fly shown in Fig. 

 9, J), the apparent segment behind the sixth, becomes modified to form 

 a sclerotized tube into which the terminal segments, which (with the 

 cerci) are modified for piercing, are retracted; and in other trupan- 

 eids such as T oxotrypmiea curvicajuda^ the apparent seventh segment 

 of the female forms an elongated sharply curved structure which is 

 longer than the rest of the body. 



Loew (1862, p. xv) refers to the egg -laying apparatus of such 

 Diptera as those mentioned above, as the "ovipositor", and states that 

 such an "ovipositor" is called "according to its form either the borer 

 (terebra) or the style (stylus)." Such an "ovipositor", however, is 

 not homologous wdth the terebra of Hymenoptera and other insects; 

 and the slender terminal portion, called the stylus by Lowe, is not 

 homologous with numerous other structures to which the designation 

 style, or stylus, is applied. It is therefore inadvisable to apply tlie 

 designation terebra or style, to these structures in female Diptera; 

 and, as was mentioned above, the egg-laying apparatus of the Diptera 

 is not homologous with an ovipositor of the orthopteroid type, so that 

 it is preferal)le to discard such terms as stylus, terebra, ovipositor, etc., 

 for these .structures in the Diptera, in favor of such designations as 

 oviscapt, or ovicauda, etc.. for the parts in question. 



4. The terminal abdominal structures of male Diptera 



In most Nematocera and other lower Diptera, the segments an- 

 terior to the genital segments do not as a rule differ markedly from 



* According to Berlese (1902) the postabdomen of the female housefiv plays an 

 important role m the mating process. 



