142 Orthorrhapha brachycera. 



of labrum, but it has a long connecting membrane; the labella are 

 relatively long, almost twice as long as the small basal part of labium, 

 somewhat broad, and cleft to the base; they are somewhat hairy. 

 Thorax is rectangular, somewhat arched above. Prothorax is small, 

 but distinct, it has two curious, strong and straight bristles above, 

 one on each side, and sometimes some hairs on the sides. Meta- 

 thorax is very small, and I could lind no chitinised metasternum. On 

 the thoracic disc there are dorsocentral and acrostichal bristles; they 

 are very short to medium long; generally the dorsocentral bristles 

 are uniserial, the acrostichal bristles biserial or more or less regularly 

 quadriserial ; sometimes they are all pluriserial. Generally a humeral 

 bristle, a posthumeral, one to three notopleural, a supraalar and a 

 postalar bristle present, rarely some of them mav be absent, but the 

 notopleural bristles are always present. Scutellum has generally four, 

 sometimes more marginal bristles. Metapleura are bare. Abdomen 

 is more or less slender, especially in the males; it is cylindrical, or 

 in the male it may be a little compressed, and in this sex it is not 

 much narrowed towards the apex. It consists of eight segments; the 

 iirst segment is short and a little broader than the following, the 

 second is the longest. The male genitalia are very uniformly con- 

 structed and somewhat curious; the tw^o last abdominal segments are 

 much lower than the preceding, and as their dorsal side is hidden 

 under the genitalia, it looks as if there v^ere eight ventral, but only 

 six dorsal segments; the eighth ventral segment is as a rule some- 

 what large. The genitalia are more or less, often strongly compressed 

 "with a sharp edge downwards or backwards; they consist of a pair 

 of lamellæ, which at the end bear some small spines; they are 

 directed forwards, and the spines are generally hidden under the 

 sixth dorsal segment. Quite hidden between these lamellæ is found 

 a pair of sinuous or angular, somewhat styliform pieces, at most the 

 ends of them may be seen anteriorly between the lamellæ; I think 

 the lamellæ are the lower and the inner pieces represent the upper 

 lamellæ. Below the lamellæ lies a large, compressed piece with a 

 more or less sharp edge, which is I think the ventral lamella; it 

 terminates above with a slender process, which is curved forwards 

 between the lamellæ. Penis is exceedingly thin, thread-like, curved 

 upwards and forwards and quite hidden in or below the ventral 

 lamella and between the lateral lamellæ. In the female the abdomen 

 is more robust and suddenly pointed; the seventh and eighth segment 

 are very narrow and often drawn back into the foregoing; after the 

 eighth segment follows a very narrow ring, terminating with two thin 

 styles. The legs are generally not specially long; in the male the 



