486 R. OSTEN SACKEN 



ridge here, in both sexes ; in D. brevicornis ^ it is developed 

 into a small hornlike appendage (see Trans. Ent. Soc. 1. c. 

 fig. 2); in Z). turgida it is much smaller; still smaller in the 

 females. The very small and closely approximated ocelli are 

 placed (as in Phytalmia) on the top of the vertex ; besides the 

 two erect bristles behind them , there is another bristle , some 

 distance in front, on each side near the orbit , which does not 

 exist in Phytalmia; still lower down, not far from the orbit, a 

 little above the antennae, there is, on each side, a minute erect 

 bristle (sometimes two) , which also exists in the other genus. 

 The antennae are like those of Phytalmia; the arista is likewise 

 feathery on one side only. The minute fringe of hairs, described 

 by D.' Gerstaecker as existing on the underside of the second 

 joint in Ph., I do not perceive here. The occiput is less deve- 

 veloped and as the anterior part of thorax is less prolonged, 

 than in Ph., the connection between head and thorax looks more 

 close, less neckHke. The thorax is more rounded and compact ; 

 its structure , in the main is the same : the part of the meta- 

 thorax between the foot of the halteres and the root of the 

 wings is more swollen. The metathorax is very flat and ver- 

 tical. The structure of the legs is the same, only they are less 

 long and a little stronger ; the front femora have a single spine 

 on the underside in the </ (two or three in Ph.) , none in the 

 9 . The abdomen of the d^ has four, that of the 9 five seg- 

 ments ; the first segment (petiole), is shorter than in Ph. ; the 

 ovipositor is about -/g of the abdomen in length, in the shape 

 of a narrow funnel (convex above and below , and gradually 

 attenuated towards the tip. 



It is not easy to assign to Phytalmia and Diplochorda a fit- 

 ting position in the system, as it exists at present. Gerstaecker, 

 in describing it among a number of Ortalidae, seems to assume 

 its membership in that polymorphous family. At least Loew 

 takes it so (Monogr. N. Am. Dipt. Ill , 27) when he quotes 

 Phytalmia among the Ortalideous genera , introduced by Ger- 

 staecker. But neither of these authors discusses the question 

 further. The structure of the funnelshaped ovipositor of the two 



