214 



[Februiirj-, 



This genua contains a rather heterogeneous collection of small 

 flies, including all those black-legged species whose males have con- 

 tiguous eyes, which cannot be placed in any of the preceding genera. 



Several small species are embraced in this group which are very 

 difficult to determine, as they are very much alike, and do not possess 

 any very marked distinctive characters. Several different species 

 have, I believe, been described under the same name, and I think that 

 the same species may have been described under different names ; so 

 that it is veiy difficult to arrive at just conclusions. The females of 

 distinct species are, in some cases, so similar, that it is almost impos- 

 sible to name them correctly, unless they are found associated with 

 the corresponding males. 



P. FLOccosA, Macq. 



The males of this common species may at ance be recognised by the tuft of hairs 

 on the under-side of the base of the liind femora, and by tbe inner sides of the hind 

 tibise being ciliated along the middle part of their inner surfaces ■with a series of 

 short bristles of unequal lengths. There is but little doubt that this species is the 

 same as the M. floralis, of Fallen, Meigen, Zetterstedt, Schiner, and others ; for the 

 general descriptions of both species agree together, though none of the last-named 

 authors mention the tufted femora. The face is rather prominent ; the eyes (of 

 male) sub-contiguous ; the arista pubescent ; the thorax marked ■with three rather 

 broad and widely separated stripes ; the abdomen narrow and rather tapering, ■with 

 a ■wide, black, dorsal, longitudinal stripe, which becomes narro'wer towards its ex- 

 tremity, and is more or less dilated opposite the upper margin of each segment, which 

 is marked with a narrow, transverse, black line. The female has the eyes separated 

 by a ■white, intra-ocular space, occupying about a third of the width of the head, con- 

 taining a •wide central, stripe, usually red at its front part, and black behind ; but 

 sometimes entirely black. The thorax and abdomen are both lighter in colour than in 

 the male, and are indistinctly striped ; the latter is oblongo-ovoid in shape, ■with the 

 apex pointed. 



The larvae feed upon the stems of cauliflowers and other varieties of the cabbage 

 tribe. I have received specimens of the fly from Mr. Inchbald, bred from the first, 

 and I reared several myself last summer from cabbage plants sent to me by Mr. 

 Dunn, of Dalkeith, in consequence of their being infested with the "grubs of the 

 cabbage-fly." 



The larva3 of A. floralis are said, by Zetterstedt and Schiner, to feed upon ra- 

 dishes {Raphanus sativus), andi Winnertz has bred this fly from the roots of Brassica 

 napoirassica. 



P. TRAJTSVERSALIS, Zett. 



This species has the abdomen oblong, flattened, rather short, covered ■with soft 



hairs, and marked along the dorsum ■with a widish, longitudinal, black band of even 



•width, interrupted opposite the edges of the segments, ■which are bordered by a 



whitish line. The thorax is very dark grey, marked with three indistinct, longitu- 



