and of several Brachycerous families in Dvptcra. 295 



My stutly of the Phorklye is based on about a dozen 

 species belonging to four, or if we admit Apiochmta of 

 Brues, five genera, and in all the characters of the trophi, 

 with the exception of the palpi, have been very constant, 

 while in the Dolichopodida3 they vary greatly. The short 

 predaceous labium of Aphrosylus, Dolichopus or Medcterus, 

 lengthens in some Gymnopterwps (G. assimilis, StiBg., for 

 example), and is specialised for flower feeding in Orthochile, 

 while Psilopus toieclcmannii, Fin., has lost the curious 

 characteristic tracheae of the family. I therefore point out 

 that the affinities pointed out are most readily seen and 

 understood in the genera, Dolichopus, Aphrosyhis and 

 Iledeterios. 



4. The structure of the compound eyes.— The 

 character of the pubescence on the eyes is similar in some 

 Dolichopodida;! and Phoridre ; it has been fully discussed 

 in section 5. 



5. Characters in the male genitalia, — The Doli- 

 chopodida3 in the majority of species, have the hypopy- 

 gium much developed, free, and attached to the abdomen 

 by a membrane ; the forcipes interiores and palpi genita- 

 lium are outside the cavity of the hypopygium. Similar 

 conditions are only found in the Phorida3, the two famihes 

 sharing these characters, though the armature is unlike in 

 detail and general arrangement. 



6. Characters in the female genitalia. — In the 

 DolichopodidiB the ovipositor is similar in type, though 

 with one joint more — all the Phoiidse examined having 

 six segments in the abdomen and three in the ovipositor, 

 while D. griseipennis, Stan., has five in the abdomen and 

 four in the ovipositor. The receptacula are also soluble in 

 the preparation of the insect. This is common in the 

 Nematocera, but quite rare in the Brachycera. 



7. Predaceous character. — This calls for evidence 

 as it has not before been touched on. {a) The structure 

 of the mouth parts in the hypopharynx and labrum sug- 

 gests a raptorial habit, (h) The legs also, (c) A prepar- 

 ation of the female of P. rnfipes shows in the contents of 

 the abdomen, the appearance which I associate with the 

 digested blood or juices of insects, (rf) I have in my 

 cabinet a small acalyptrate Muscid which I took out of the 

 grasp of P. concinna^. Both are mounted on the same card, 

 and till I examined them with a lens, I was under the 

 impression that they were "m copula" ; unfortunately the 



