318 DIPTERA OF NORTH AMERICA. [PART IV, 



the cells in the apical portion of the wing, the basal cells are 

 short ; the first is longer than the second. 



1 am uncertain about the sex of my specimens, as the tip of the 

 abdomen shows no trace either of a forceps or of an ovipositor ; 

 I am inclined to think that they are females, and that the ovi- 

 positor of this genus has very short, almost indistinct horny 

 appendages, or none at all. 



The next relatives of Frotoplasa are, the amber genus Macro- 

 chile Locvv, and the Chilian genus Tanyderus Philippi. 



Tanyderus^ Philippi (Verh. Zool. Bot. Gesellsch. in Wien, 18G5, 

 p. *I80, Tab. XXIX, fig. 57) shows, in almost all respects, the 

 greatest resemblance to Frotoplasa; the same large suctorial 

 flabs and long palpi ; long neck ; projecting scutellum ; venation 

 almost identical ; anal angle likewise square, only more pointed ; 

 the wings pictured in a similar manner. The only differences 

 which I can discover are : the antennte are longer and consist of 

 at least twenty-five joints, the last ones being difficult to count ; 

 the first vein and both branches of the second vein are very much 

 arcuated, whereas they are nearly straight in Frotoplasa ; there 

 is no supernumerary cross-vein in the penultimate posterior cell, 

 but there is one in the first posterior cell (which does not exist 

 in Frotoplasa). " The abdomen of the male," says Dr. Philippi, 

 "ends in two filaments." As this author had only one of the 

 sexes before him, did he not mistake the female for a male? 

 Tanyderus is represented by a single species, T. pictus, from 

 Chile. 



Macrochile!^ Loew (Linnsea Entomologica, Vol. Y, p. 402, 

 1851, Tab. II, fig. 24) is also remarkably like Frotoplasa ; nearly 

 the same venation, the same square anal angle,' long proboscis, 

 large lips, and long palpi. The only striking difference in the 

 venation is, that the supernumerary cross-vein in the penultimate 

 posterior cell, which distinguishes Frotoplasa, is wanting here, 

 as in Tanyderus, and that the prasfurca is rounded near its 

 origin, and has no stump of a vein. The eyes of Macrochile 



' From ravvo), to extend, and Jsp», neck. 



2 From /naxpof, large, and x^'^"!^ 'ip- 



" This is not mentioned in Mr. Loew's description, nor represented on 

 his figure, but I have ascertained it on the original specimens, which I 

 have seen. The statement about the structure of the collare, which I 

 make further below, I owe to a written communication of Mr. Loew. 



