284 Mr. W. Wesche 07i systematic affinities of the Phoridx 



them both in a sub- family, " Energopoda," with the Asihdas 

 and Empidse, placing the group at the end of the Orthorra- 

 pha.* Herr. Theo. Becker thinks that they are derived from 

 Nematocerous forms allied to the Mycetophilida) and 

 notices the structure of the bristles found only in the 

 Phoridas and Mycetophilidae.f 



Schiner in his "Fauna Austrica" placed them between the 

 BibionidiB and the Borboridae, but whether for convenience, 

 or on account of affinity is not clear. 



Not one of these authors is sure whether this family 

 belongs to the Orthorrapha or to the Cyclorrajjha, and 

 nothing definite seems known about the mechanism of 

 the pupa-case. 



The problem being so difficult of solution, Osten-Sacken 

 even going so far as to say that " a real affinity with Phora 

 does not exist anywhere," it niay seem presumption in me 

 to attempt to solve it, as I certainly have no jiretensions 

 to a comprehensive knowledge of exotic species of Diptera. 

 But I am encouraged to present my views, as I attack 

 from a new position, none of these writers with the possible 

 exception of Becker having made much use of the micro- 

 scope, while the great majority of the observations from 

 which my conclusions have been arrived at, are founded 

 on the anatomy and microscopic structure, the minute 

 size of these insects mostly requiring a magnification of 

 250 diameters fur a good view of such organs as mouth 

 parts or genitalia. 



After an examination and comparison of a number of 

 preparations, and a study of the genitalia of several species 

 of Phoridas, (I was already familiar with the Muscid forms), 

 I came to the conclusion that they have no real affinities 

 either to the Borborida' or the Hippoboscida?, the families 

 that are placed before and after them in Mr. Verrall's list 

 of British Diptera. Further, they are sharply divided from 

 any of the Muscidas by the absence of the ptilinum, the 

 membrane on the head, which being inflated, is used to 

 push the cover off the pupa-case. The absence of this 

 structure raises a very strong doubt as to whether the 

 Phorida3 have any place in the Cyclorrapha ; a doubt that 

 in my mind is a certainty that they have not. 



* The position of Phora in the system of Diptera, " Ent. Mon. 

 Mag." 2nd ser., vol. xiii, pp. 204, Sep. 1902. 



t Die Phoriden. Abh. d. k. k. Zool-botan. Ges. AVien. Bd 1. 

 Ueit 1. 



