4 Pipuncnlidae. 



wards turned surface a larger or smaller, curious membraneous im- 

 pression of roundish, oval or elongated shape, often with a longitudinal 

 keel-shaped middle fold; the impression is in some species very small 

 or quite disappearing; in the other genera no such impression is 

 present, the segment here looking as if composed of two pieces, 

 separated by a longitudinal split, but this latter, I think, answers to 

 the impression, Nephrocenis I have not seen, but its hypopygium 

 seems to be principally of the same construction; the eighth segment 

 bears to the right, at the end below, the ninth segment, the real hypo- 

 pygium, which consists of a basal part bearing a pair of more or less 

 elongated triangular, somewhat claw-like appendages, and from the 

 basal part issues below the penis as a thread-like organ, curved or 

 with the end somewhat rolled up; in an excision in the basal part 

 between the bases of the claws is a pair of small, hairy lamellæ, 

 constituting the tenth segment. It will be seen that the genitalia are 

 rather like those in the Syrphidae; as there the anterior of the trans- 

 formed segments are forced to the left, the eighth lying at the end, 

 curving to the right and bearing the ninth below towards the right; 

 also the construction of the ninth segment, the hypopygium itself, 

 is similar to that in the Syrphidae. In the female abdomen is in all 

 genera composed of six not transformed segments, next to these 

 follows a curious large hypopygium, consisting of two segments, the 

 first forming an oval or more roundish or cordate, sometimes elongated 

 basal part, ending in a longer or shorter, thin and pointed ovipositor, 

 which is straight or more or less incurved, or on the contrary, recurved. 

 The ovipositor is semitubular with a ventral (upwards turned) canal ; 

 on the dorsal side at the base of the ovipositor is an opening, in which 

 two small lamellæ are placed, answering to the last segment; this 

 opening is thus the morphological end of the segment forming the 

 ovipositor, and the ovipositor itself is a ventral prolongation of the 

 segment. The hypopygium is bent in under the venter. According to 

 the above, the female abdomen would consist of only nine segments, 

 but I think a small segment may be present between the sixth and 

 the hypopygium, or else it has quite disappeared. In Nephrocerus 

 there are, in addition to the parts mentioned, two semicircular pro- 

 minent swellings below the sixth abdominal segment. In Pipiinciilus 

 abdomen is generally sparingly and short-haired, in the other genera 

 it has longer hairs especially at the sides; at the sides of the first 

 segment there is always a bunch or fan of longer hairs, but they may 

 be more or less conspicuous and contrasted to the other hairs at the 



