364 C R. Osten Sacken: On Prof. Brauers papcr: 



graphs of N.-Am. Dipt. Vol. I, 1862, with a single sliglit modification.*) 

 As a catalogue - maker I was not called upon to refovm, and therefore 

 I adopted that distribution, although in several points I dissented from it. 

 Since then, I liave matured my views ou the subject; and I will avail 

 myself of the present opportunity in order to state my objections; they 

 refer to the family Xylophagidae. 



I. In the first place I object against the juxtaposition of Subula 

 and J^l/lophagus in the same iiltimate subdivision. Since Meigen, 

 in the infancy of dipterology, united both forms in the same genus, 

 routine and nothing eise seems to have indueed authors to keep them 

 together. What have they in common? Head, trophi, palpi, antennae, 

 thorax, abdomen, legs, venation, oflfer difiFerences that are obvious, and 

 some of them are even of a higher order than mere generic differences. 

 In Subula, the prosternal plate, intervening between the front coxae 

 and the anterior thoracic orifice is large; the front coxae short; the 

 abdominal segments but little extensile; in these characters Subula is 

 like the Beridina. In Xylophagus, on. the contrary, the prosternal plate 

 is small, and hence, the interval between the front coxae and the anterior 

 thoracic orifice is short; the front coxae are inserted very near the 

 head; they are long, cylindrical and very movable; the abdominal seg. 

 ments are loosely joined, with extensile connecting membranes; all these 

 characters are those of the group Tabanidae-Leptidae. A conclusive 

 proof of this double relationship is afforded by the metamorphosis of 

 these genera: the larva of Subula resembles those of some Stratiomyidae 

 and its pupa remains within the larva- skin; the larva of Xylophagus 

 is more like that of the Tabanidae, and its pupa throws off the larva- 

 skin, ^) — Still another argument in the same direction is supplied by 

 the anatomy of those diptera. In Dr. Brand t's Vergl. anat. Unters. 

 über d. Nervensystem d. Dipteren (Horae Soc. Ent. Eossicae XV, p. 97) 

 1 find that the formula for the distribution of the cephalic, thoracic 

 and abdominal ganglia is the same for Xylophagus cinctus and Leptis 

 tringaria and scolopacea (2, 2, 6); while it is different in the Tabanidae 

 (2, 1, 4—6) and Stratiomyidae (2, 1, 4). — The nervous Systems of 

 Xylophagus and Leptis, as represented on the plates (fig. 11, 27, 28) 



') Loew's section Coenomyina I retained as a separate family. 

 Mr. Beling's discovery of the larva of Coenomyia has proved since, 

 that its relationship to Xylophagus is much closer than I had supposed. 



^) Dr. Brauer is aware of the differences between Xylophagus 

 and Subula, but he does not attach to them the same importance as 

 I do. (See his p. 5 at the bottom and passim). 



