Dipterous Genus Xylomyia, Rond. 189 



the imagines, larvse, mode of pupation, and nervous system 

 of the larvse) used by Osten Sacken in his paper of 1882, to 

 which reference has already been made, to divorce Subulu 

 from Xylophagus and substantiate its inclusion among the 

 Stratiomyidse (Beridina), especially as the paper in question 

 is written in English. But it may be interesting to note that, 

 as pointed out by Osten Sacken himself, his conclusions (at 

 least so far as concerns Subula) were anticipated by Latreille 

 and Westwood. The latter, in the ' Introduction ' &c. vol. ii. 

 pp. 533-534, and in the appended " Synopsis of the Genera 

 of British Insects," p. 130, makes a family Beridse, to include 

 the genera JSubula, Beris, and Actina, and another — the 

 Ccenomyidse — comprising Xylophagus and the non-British 

 genera Pachystomus ( = Xylophagus) and Ccenomyia. West- 

 wood, however, erred in including his Ccenomyidse among 

 the Notacantha. 



In 1891 Osten Sacken formally merged his Xylophagidse 

 (i.e. Xylophagus + Ccenomyia) in the Leptidse, the death- 

 warrant of the former family running as follows : — " The very 

 problematic family of Xylophagidse must be given up, and 

 its contents, temporarily at least, united with the Leptidse " *. 

 Prior to this (in 1886 — Biol. Centr.-Am.) Osten Sacken had 

 placed Subula at the head of the family Stratiomyidse ; and in 

 this connexion it may be remarked that the Beridina are 

 placed by Osten Sacken at the commencement of the Stratio- 

 myidse t instead of at the end, where they (Berinse) are to be 

 found in Schiner's Catalogue as well as in Verrall's ( List,' 

 and in one of the recent catalogues by van der Wulp L The 

 position of Xylomyia at the commencement of the Stratio- 

 myidse instead of at the end is supported by a study of the 

 venation, which exhibits several noteworthy divergences from 

 the ordinary Stratiomyid type: it is sufficient to refer to the 

 shape of the discal cell, which is very different from that 

 which is a special characteristic of the Stratiomyidse. 



The conclusion, therefore, at which we arrive is that 

 Xylomyia represents a primitive ancestral form of Stiatio- 

 myid, given off from the common stem after the evolution of 



* C. R. Osten Sacken, " Suggestions towards a better Grouping of 

 certain Families of the Order Diptera," Ent. Month. Mag. ser. 2, vol. ii. 

 (1891) p. 38. 



t C'/. ' Catalogue of the Described Diptera of North America ' [2nd ed. I 

 1878, p. 43. 



X V. d. Wulp, ' Catalogue Described Dipt. S. Asia ' (1896), supra cit. 

 p. 58. In the recently published ' Nieuwe Naamlijst van Nederlandsche 

 Diptera, door F. M. van der Wulp en Dr. J. C. II. De Meijere. — Uitge- 

 geven door de Nederlandsche Entomologische Vereeniging als Dijvcegsel 

 tot deel xli. van bet Tijdschrift voor Entomologie ' ('S Gravenhage, 

 Martiuus Nijhoti, 1898), the first genus of tbeStratiomyidaj is Beris. 



