March, 1833.] 217 



tudinal lines. The abdomen is flat and tapering, having a central, longitudinal, 

 black, doi-sal stripe, as well as transverse dark lines on the borders of the segments ; 

 the latter being only visible in certain lights. The anal segment is small and grey, 

 and the sub-anal appendages of moderate size. The face and epistome are often rufes- 

 cent, and are both slightly prominent ; the eyes are sub-coherent in the male, and 

 widely separated in the female ; the latter having the intra-ocular space red at the 

 fore part ; the I'ow of bristles on the inside of the hind tibise of the male consists of 

 short rigid hairs, placed very near together, and of almost equal lengths. The female 

 has the thorax of a paler brown colour, and is indistinctly striped. 



This little fly is generally distributed, and feeds, in the larva state, upon onions. 

 I bred a number of specimens of both sexes last summer, from onion plants, in 

 different stages of growth, which had been kindly sent to me by Miss Ormerod, as 

 well as by Mr. Dunn, of Dalkeith, in consequence of their being infested by the 

 maggots or larvae of Diptera, which were injurious to the onion crops. 



I have placed the A. ruflceps, of Zetterstedt, as a synonym of P. cilicrura, 

 though Rondani thinks that it agrees more closely with A. angustifrons, of Meigen ; 

 the latter species, however, has a decidedly prominent face, and Zetterstedt says of 

 A.fusciceps, " frons parum prominula." The hind tibiae, again, in A. angustifrons 

 (a typical continental specimen of which, named by Rondani, I have had an oppor- 

 tunity of examining), are furnished with much longer and softer hairs than those of 

 P. cilicrura; and Zetterstedt says of A.fusciceps, "tibiae posticae intus pube brevi 

 erecta ciliatae." I have not seen a British specimen of A. angustfrons. I formerly 

 confused it with P. cilicrura. 



P. TEICHODACTYLA, Roud. 



This species very closely resembles P. cilicrura, but is usually rather smaller, of 

 a lighter grey colour, and has the thorax less distinctly striped, being often im- 

 maculate. The abdominal dorsal stripe is generally interrupted, the separate 

 portions having a triangular shape. The hind tibiae of the males are armed exactly 

 like those of P. cilicrura, but the middle legs present a very characteristic difference, 

 the metatarsal joints being furnished on their outer sides with four or five long 

 curved hairs or bristles. I only know the male. 



This little fly is not uncommon, but less frequently seen than the preceding one. 



P. FLOEILEGA, Zett. 



This species closely resembles P. trichodactyla in form, colour and design, but 

 has the middle metatarsal joints of the males destitute of long hairs, and the inner 

 surfaces of the hind tibiae unarmed, with the exception of having two or three short 

 bristles at their upper part. It is about 3 mm. in length, has both the face and 

 epistome slightly prominent, the eyes of the male contiguous, the arista bare, the 

 thorax yellowish-grey, marked with three indistinct brown stripes ; the abdomen 

 flat, narrow and tapering, with very small anal and sub-anal appendages ; cinereous 

 in colour, and marked with a sub-continuous dorsal stripe, which is quite straight, 

 and of uniform width throughout. T do not know the female. 



Not uncommon. 



P. iGfNOTA, Rond. 



This is a well-marked little species, very common in gardens and fields. It is 



