222 [March, 



males ; ocelli large and prominent ; frontal bristles wanting ; arista 

 bare, or pubescent ; alulets small, but with the scales usually unequal 

 in size ; abdomen cylindrico-conical, with only four distinct segments, 

 each of which is mostly marked with three spots, one central and 

 elongated, and two lateral and round ; wings veined as in the Homa- 

 lomyice, but with the axillary less approximated to the extremity of the 

 anal veins : hind tibiae of the males often bearded on one or the other 

 side with long hairs. 



Females with the eyes separated by a moderately wide space, fur- 

 nished with a single row of small bristles on each side ; abdomen 

 pointed, and marked as in the males, but with smaller spots. 



Sect. 1 — Halteres pal 



1. Macquarti, Stseg. 



triquetra, p. Macq. 



2. Zetterstedti, Eond. 



triquetra, Fall, et Zett. 



3. cilipes, Hal. 



triquetra, p. Macq. 

 tibialis, Staeg. 

 Stcegeri, Zett. 



4. triquetra, "Wied. et Meig. 

 nudipes, Zett. 



5. gibbera, Meig. 

 cerea, Zett. ? 



Sect. 2 — Halteres black. 



6. ATERRIMA, Meig. 



This- group, though closely related to the Homalomyice, is well 

 characterized, and has been recognised as forming a distinct genus by 

 most modern authors, except Schiner, who, in his most valuable work 

 (Fauna Austriaca, Diptera), still retains it in his great and hetero- 

 geneous genus Antliomyia. Jt was elaborately monographed by H. 

 Loew in 1874,* and revised by Eondani in 1877.f 



The British species in the first section may be thus tabulated : — 



Hind tibiae of $ with long hairs on both outer and inner sides... 1. Macquarti. 



„ „ „ on inner sides only 2. Zetterstedti. 



„ „ „ on outer sides only 3. cilipes. 



„ „ „ on neither side 4. triquetra. 



All these four species have the alulets and wings more or less fuscous or nigres- 

 cent. A. Macquarti, which is the most common, is also usually the largest ; besides 

 having long cilise on both sides of the hind tibiae, the males are also furnished with 

 a single long straight bristle in the middle of the under-side of the middle femora. 

 The females sometimes have the fore tibiae piceous, or even testaceous, and may be 

 found in abundance on horse-droppings in roads in woody places. I know of no 



* Entomologische Miscellen., Breslau. f Dipterologise Italic* Prodromus, Vol. vi. 



