414 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



less so in Halictoxenos and truncate at apex, and in the true Xenini 

 it is constricted, pedunculate at apex. 



Dionocera (Diozoceridae) has a short broadly rounded scutellum. 

 In all the Halictophagoidea and Elenchoidea the scutellum is short 

 and transverse, but variously carved or truncate on its anterior 

 margin (pis. 74-78), 



In other orders of insects the scutellum laterally reaches the 

 posterior attachment of the wing, being connected therewith by 

 the axillary cord. In the Strepsiptera the base of the scutellum is 

 very far behind the posterior attachment of the wings, but in several 

 genera {Triozocera^ Neostyloys^ Xenos) there is a cord from the 

 base of the wing running back and attached to a tiny sclerite on the 

 epimeral area (pi. 65, fig. 6; pi. 66, fig. 7; pi. 70, fig. 4; pi. 72, fig. 

 1 ) . In Xenos vesparurti there is a small piece detached from scutel- 

 lum but next to it and between the parascutellum and postscutellum, 

 and beyond this is the little piece to which the cord is attached. This 

 would indicate that two little pieces of scutellum have separated off 

 and in later genera disappeared completely (pi. 72, fig. 1). 



Posilumhium. — This flexible area behind the base of scutellum is 

 always present and always transverse. It lies in an emargination 

 of the base of the postscutellum, practically at the transverse axis of 

 the hodij. It is usually soft intersegmental skin, but in Eupathonera 

 is chitinized and of the same texture as the remainder of the notum. 

 (See all plates with illustrations of males.) 



PostscutelluTn. — The fifth median zone of the metanotum (count- 

 ing scutellum as the second) is the postscutellum, which is the largest 

 single piece on the entire body. It extends back far over the abdomen 

 and is concave, allowing considerable flexibility to the abdomen, 

 which can, to a large measure, be retracted into it in some genera. 

 (See all plates with illustrations of males.) 



Pretergite and prealare. — Pretergite occurs in front of the prae- 

 scutum, but so far has only been seen in Delphaeixenos anomalocerus 

 (Halictophagidae). The prealare is recognizable besides the scutum 

 or praescutum and in front of the base of the wing (pi. 75, fig. 2). 



Wing sclerites. — A number of tiny pieces occur around the attach- 

 ment of the wing, but have not been carefully studied (pi. 64, fig. 2; 

 pi. 75, fig. 2). 



Pleurotergite. — Between the postscutellum and epimeron or hj^po- 

 epimeron is an elongate area known as the pleurotergite, and prob- 

 ably derived from the postscutellum. In Tetrozocera and other 

 genera this is apparently divided into two pieces (pi. 66, fig. 3). 



Wing. — The wings are attached far front on the metathorax, being 

 surrounded at their base by prealare, tegula, scutum, parascutellum, 

 epimeron, and episternum, with certain tiny pieces difficult to under- 



