362 ME. WALTER WES CHE ON THE GENITALIA OF 



The Vltimate Segment of the Ovipositor. 



In families where the ovipositor is not extruded this part does not call for remark. 



StratiomyiidcB. — In Beris and Stratoinys chameeleon it is a chitinous plate with no 

 suggestions of other structure, though the edges in B. valata are convoluted and 

 thickened transversely. 



Empidce. — In the Empidse it consists of a dorsal and ventral plate, 



Bolichopodidce. — In Bollchopus griseipennis there are indications of the formation 

 of two chitinous rods. On the ventral side, at the extremity, is a sensory membrane, 

 covered with minute triangular plates (PI. 25. fig. 52). In Fcecilobothrus nohilitatus 

 four rods show qviite plainly. 



Syrphidce. — In Syritta 2npiens arc two chitinous levers whicli appear to be the 

 continuation of the valvular, and there is a darkening of the chitin suggestive of the 

 formation of a rod. 



In Eristalis intricarius there are three transverse ridges of chitin with setae. In the 

 middle is tiie opening of a gland which is probably a glue-gland. 



MuscidcB. — In Musca domestica this part contains four chitinous rods which are 

 shorter and stouter than the rods in the following sections; there are also several 

 transverse setose ridges. The membrane between this and the penultimate segment 

 has minute triangular sensory plates (PI. 29. fig. 107). 



In Calliphora erythrocephala there are no rods, the part consisting of a dorsal and 

 ventral plate ; there are apodemes from the valves. 



In Polietea lardaria are two transverse setose ridges, dorsal and ventral ; the rest of 

 the part is transparent membrane. 



In Vlidia nigrlpennis this segment consists of apparently three plates forming a 

 rod-like piercing-organ. 



In Norellia spinimcma this segment is part of the abdomen, and appears to consist of 

 a chitinous plate, and bears the remarkable process of short spines already alluded to 

 (PL 28. fig. 90). 



The Penultimate Segment. 



Stratiomyiidcc. — In Beris vallata and B. nigra plates, which do not quite encircle the 

 abdomen, are found in this place. In S. chameeleon what seems to be the opening of a 

 "■land and lateral processes are found on this segment. 



Empidce. — In the Empidae two plates usually form this part. In Hilara cilipes is 

 the curious notched process previously alluded to, and in the interior wall is the opening 

 of a glue-gland (PI. 25. fig. 42). 



BolichopodidcP. — In Dolichopus griseipennis this part appears to be quite membranous ; 

 there is also a glue-gland with a funnel-shaped opening in the interior wall (PI. 25. 

 fio-. 52). In B. festivus three plates are present, as is also the case in Boecilobothrus 

 noLilitatus, where there are also suggestions of the formation of rods. 



Syrphidce — In Syritta pipiens the part presents no noticeable structure. 



Iluscidce. — In Musca domestica, at the posterior part of the segment, are four small, 



