Xo. 64] DIPTERA OF CONNECTICUT: MORPHOLOGY 93 



male organ, labelled ae in the male mosquito shown in Fio;. 11, A, 

 appears to be homologous with the structure called the aedeagus in 

 male insects in general. Older writers refer to it as the penis (a term 

 restricted b,y recent entomologists to the membranous eversible struc- 

 ture through which the ejaculatory duct discharges to the exterior), 

 while many recent culicidologists such as Freeborn (1924) and others, 

 follow Christophers (1922) in calling it the phallosome, although 

 Alexander and other students of the Tipulidae restrict the term 

 phallosome to the structure labelled j^hs at the base of the aedeagus ae 

 of the male tipulid shown in Fig. 7, J, and the latter usage has much 

 to recommend it. Edwards (1920) suggests that it be called the 

 mesosome (as proposed by Waterston, 1914) instead of phallosome, 

 and states that it corresponds to the structure called the theca by 

 Christophers (1922) — a term applied to a wide variety of structures 

 in other insects. Although there can be no serious objection to call- 

 ing the male organ ae of a male mosquito (Fig. 11, A) the phallo- 

 some, it is preferable to refer to it as the aedeagus, in conformity 

 Nvith the general application of this term in other insects. 



The so-called "tenth segment" of male culicids is apparently a 

 composite structure formed by the union of the tenth segment, the 

 cercus-bearing eleventh segment, and the anus-bearing, non-segmental 

 telson. If the appendages it bears are formed by the cerci (as Chris- 

 tophers, 1923, maintains), the cercus-bearing eleventh segment is 

 probably involved in its composition, so that it is inadvisable to refer 

 to it as the "tenth segment" or the "anal segment". Since it is ap- 

 parently a segmental complex, it should be designated as the procti- 

 ger, or anus-bearing segmental complex which is referred to by this 

 name in lower insects. 



The structures labelled pr in Fig. 11, A, are apparently formed, 

 at least in part, by the cerci, since Christophers (1923) has shown 

 that their distal portions, at least, correspond to the cerci of female 

 mosquitoes. Freeborn (1924), on the other hand, refers to these 

 structures as the paraprocts or parapodial plates, although the occur- 

 rence of distinct paraprocts in the Dipt4?ra has not yet been definitely 

 demonstrated. While it is quite possible that the paraprocts may 

 enter into the composition of the structures in question, it is also 

 quite possible that the paraprocts may form the bipartite plate in 

 the ventral region of the "anal segment" of certain Nematocera, and 

 until the homologies of these structures have been definitely deter- 

 mined, it is preferable to refer to the structures labelled pr in Fig. 

 11, A, simply as the "cerci". 



The Tenninalm of Male Orthorrhaplious Brachycera. The Rha- 

 gionidae (Leptidae) and Therevidae are the most primitive repre- 

 sentatives of the orthorrhaphous Brachycera, and have retained many 

 of the characters of the Anisopodidae, Bibionidae and Mycetophilidae, 

 which approach the lower Brachycera in many respects. The genital 

 forceps c.vi and st of the rhagionid shown in Fig. 12, A, are not very 

 different from those of typical male Nematocera; and even in some 

 of the higher members of the orthorrhaphous Brachycera (e. g., the 



