18S2.1 



223 



specific characters by which they may be distinguished from the females of the allied 

 species. A. Zetterstedti has the long ciliae of the hind tibiae arranged in a double 

 row on the inner and anterior sides, and has two or thi*ee strong bristles on the 

 under-surface of the middle femora. This little species (usually the smallest) is not 

 uncommon. I do not know the female. A. cilipes has the beard on the hind tibia? 

 of the males longer and stronger than in either of the other species, and placed on 

 the outer (or rather hinder) sides only ; it has also a single very long bristle pro- 

 jecting straightly outwards a little before the end of the tibia below the beard. The 

 legs are all more or less piceous, the tibia? being often testaceous. In size it nearly 

 equals A. Macquarti, the males being about 5 millimetres in length. It is not 

 common. The female is unknown to me. A. triquetra is about the size of A. 

 Zetterstedti, or a little larger, the males measuring from 3£ to 4 millimetres in 

 length. It is easily known by its simple hind tibia?. There is usually one long 

 bristle on the under-side of the middle femora, as in A. Macquarti. It is generally 

 distributed. I have not seen the female. 



A. gibbera, Meig. 



This little species, from 2k to 3 millimetres in length, has black halteres, as well 

 as nigrescent alulets and wings ; the thorax is deep black ; the abdomen is dark 

 grey, marked in the ordinary manner, but with the spots large and sometimes con- 

 fluent, when they become indistinct ; the scales of the alulets are very small, and 

 almost or quite equal in size ; the hind tibia? are ciliated on the under-side with long 

 hairs arranged in two rows. Very rare. I have only seen one male, captured by 

 Mr. Verrall at Eannoch, which he kindly sent for my inspection. 



A. ATEKRIMA, Meig. 



This is an aberrant species, the abdomen being without the characteristic spots ; 

 it resembles the other species in the genus, however, by the form and structure of 

 the head, abdomen, and wings. It is entirely black, with the exception of a narrow 

 white seam on the posterior edge of each abdominal segment ; the halteres are quite 

 black, as well as the alulets, the scales of which are small and equal in size ; the 

 wings are nigrescent ; the legs are black ; there is a single straight bristle on the 

 under-side of each middle femur ; the hind tibia? are simple. Size of male about 

 3 mm. I have seen but one specimen of this little fly, also from the collection of 

 Mr. Verrall. 



15. CCELOMYIA, Hal. 



Homalomyia, Rond. 

 Aricia, p. Zett. 



Gen. cli. — Eyes of moderate size, bare, sub-contiguous in male, 

 not covering the lower third of the sides of the head ; forehead and 

 epistome rather prominent ; proboscis membranous and somewhat 

 elongated ; arista tomentose ; abdomen with five segments, very de- 

 pressed, membranaceous beneath, concave, and without plica ; alulets 

 small and sub-equal ; wings and legs as in the Homalomyice. 



