7G COXXECTICUT GEOL. AND NAT. HIST. ^IRVEY [Bllll. 



pare also Fio;. 1^. A), the sixth abdominal sejiinent might be regarded 

 as the last ^^t^gment of the preabdomen. if the designation postabdomen 

 is applied to" the slender terminal abdominal region of these insects. 

 The torsion and asymmetrical development of the segments of the 

 postabdomen of male Cyclorrhapha has been discussed elsewhere. 



Thv Tcrmmalia. The designation terminalia was apparently 

 Hrst applied to the terminal abdominal segments located behind the 

 genital segments. Freeborn (1924, p. 190), however, proposed that the 

 designation terminalia be applied to "the complex of anal and genital 

 pai-ts borne caiidad of the seventh abdominal segment." Kecent in- 

 vestigators have further extended the application of the term to 

 inchide practically all of the postabdomen of the higher Diptera 

 when the segments of this region differ from the preceding ones, and 

 this usage has been adopted here, since it has received increasingly 

 wide acceptance among dipterists in general, and the students of 

 the higher Diptera in particular. 



Some recent investigators would use the term hypopygium as a 

 synonym of terminalia (as here employed), and most culicidologists 

 follow Christophers (1923. p. 701) in applying the designation ''female 

 hypopygium" to "the eighth (in part), the ninth and the tenth 

 segments with their appendages, the intersegmental membranes and 

 the openings of the anus and genital tract" in female mosquitoes. 

 There is, however, no uniformity of opinion concerning the applica- 

 tion of the term hypopygium among other dipterists. Thus, the stu- 

 dents of the Tipulidae. such as Alexander and others, would include 

 under the designation "'male hypopygium" the eighth abdominal 

 segment as well as the succeeding ones if (as is rarely the case) the 

 (Mghth segment is especially modified — i. e.. if it becomes swollen or 

 enlarged, or if it bears lobes, hairy brushes, spines and other struc- 

 tures differentiating it from the preceding segments. Edwards (1920), 

 on the other hand, includes only the ninth and the succeeding seg- 

 ments in the "male hypopygium", and. in a footnote to page 24, at- 

 tributes this usage to Snodgrass (1904). Snodm-ass (1904, p. 179), 

 however, exi^ressly states that he restricts "the application of the vrord 

 hypopygiurn to the ninth segment only", and many dipterists have 

 followed his suggestion that the term hypopygium be restricted to 

 the ninth segment alone (i. e., without including the succeeding seg- 

 ments) in male Diptera. 



The word hypopygium (ai)parently fii-st introduced bv Westhof, 

 1882) means "under-the-rump" and is therefore hardly Applicable 

 to the "rump" or anus-bearing parts behind the genital secrment. and 

 m fact Bergroth, 1888, (Entom. Tidskr., Vol. 9, p. 138 et seq.) has sub- 

 stituted the term propygium (meaning "in-front-of-the-rump") for 

 the designation hypopygium in referring to the genital set^ments of 

 male Diptera, since he states that the genital setrments are" in front 

 of, rather than under, the rump (or proctiger)"; so that these dip- 

 tei-ists, together with Snodgrass (1904) and other investigators, would 

 excliKle the anus-bearing i)arts behind the genital segments from the 

 ai)plication of the term hypopygium, and this usage has much to 



