262 ENTOMOLOGICAL NEWS. [June, 'l6 



anteriorly to the R-M cross-vein, whereas in the Chironomidse, Simulidae, 

 and Bibionidse the radial sector is usually simple, but when it forks 

 does so beyond the R-M cross-vein. An apparent exception to this rule, 

 however, is the Bibionid genus Eupeitenus. It is also noteworthy that 

 in the families of the first group the media is primitively three- 

 branched, while in those of the second it is never more than two- 

 branched. 



Mr. Edwards disclaims having made an exhaustive investi- 

 gation, but expresses the conviction that Mycctobia belongs 

 with the Rhyphidae. The writer hopes that other workers will 

 be stimulated to take up the study of the relationships with- 

 in the Diptera, and their bearings on the new ideas. With 

 this end in view, I quote the summary at the end of Mr. Ed- 

 wards' paper : 



1. Mycetobia agrees with the Rhyphidae and diverges from the Myce- 

 tophilidae in the possession of a large gular plate, in the structure of the 

 second palpal joint, in the position of the forking of the radial vein, 

 the course of the cubital vein, and in the chitinous spermathecae of the 

 female. Since the venation of Mycetobia has been shown to be di- 

 rectly derivable from that of the Rhyphid genus Olbiogaster, it is prob- 

 able that any resemblances in this respect to the Mycetophilidae are due 

 to convergent evolution, and not to relationship. The genus Mycetobia 

 (and with it Mesochria, though not Ditomyia or Symmerus) must 

 therefore, on grounds of adult as well as larval structure, be trans- 

 ferred from the Mycetophilidae to the Rhyphidae. 



2. It is at least possible that the characters of the gular plate and 

 of the position of the radial fork will be found on full investigation 

 to divide the Nematocera into two groups, and there is evidence that 

 these groups may coincide with those founded on other characters, 

 notably the tracheal system of the larva; this evidence, therefore, 

 tends to confirm Knab's recent division of the Nematocera (Ann. Ent. 

 Soc. Amer. vol. viii, p. 93, March, 1915) into Oligoneura, with peri- 

 pneustic larvae, and Polyneura, with amphipneustic larvae. The genus 

 Pachyncura seems to require special study, owing to the intermediate 

 character of its venation, and Eupeitenus is also aberrant. 



3. If, as seems probable from many considerations, the higher 

 Diptera have been derived from the Polyneura and the Oligoneura 

 represent an entirely distinct line of evolution, the primary division of 

 the order should be neither into Orthorrhapha and Cyclorrhapha, nor 

 into Nematocera and Brachycera, but into Polyneura and Oligoneura, 

 the former including, in addition to the Tipulid-Culicid group of the 

 Nematocera, the whole of the Cyclorrhapha and the Orthorrhapha 

 Brachycera. 



