DIOCTRIA. 59 



Epistoma flat, broad, clothed with shining down on each side, beset 

 with a few bristles in front. Eyes generally green, rarely violet ; fore 

 part flat, composed of large facets. Three ocelli on the crown. Pro- 

 boscis porrect, short, almost horizontal. Labrum conical, very short. 

 Lingua subulate, flat, clothed towards the tip with short velvet-like 

 retracted hairs, as long as the labium. Maxillae subulate, flat, pointed, 

 almost as long as the lingua. Palpi short, cylindrical, truncated, 

 bristly. Labium bristly, arched beneath, channelled above, small 

 in front. Antenna porrect, 5-jointed, not stylate, seated on a tu- 

 bercle, closely approximate at the base, curved, diverging, longer 

 than the head ; first and second joints bristly ; first joint cylindri- 

 cal ; second shorter than the first ; almost cyathiform ; third long, 

 compressed ; fourth and fifth very ' short, forming an obtuse tip. 

 Thorax oval, almost bare, often striped on the back, and gilded 

 or silvery on each side. Wings lanceolate, narrow, obtuse, very 

 finely pubescent ; mediastinal areolet open. Alula? small, entire. 

 Halteres uncovered. Abdomen with 7 segments, bare, almost cylin- 

 drical, sometimes marked with yellow on each side ; first segment 

 broader and more arched than the following. Legs slender, slightly 

 bristly or quite bare ; femora and tibiae straight ; hinder tibiae finely 

 fringed with hairs ; fore tibiae slightly hairy by the spurs ; hind tarsi 

 slightly clavate. Onychia conspicuous. . 



These flies inhabit meadows, trees, and bushes, during the 

 summer, and are more abundant than those of the preceding 

 genus ; they feed chiefly on small Diptera ; some species prey 

 upon Uymenoptera. 



1. oelandica, L. s. n. ii. 1008. 1.5 (1763); Fb. ; Shr. ; Gfr.; 

 Gm. ; Mg. ; LI. ; Fin. ; Mq. ; Zll. ; Ztt. ; Lw. Nigra, thorace albido- 

 quadrivittato, alis nigricantibus, pedibus mfis, tibiis apice tirsisque 

 nigris. Long. 6-7 ; alar. 10-12 lin. 



Black, shining, clothed with black hairs. Head with a white 

 covering beneath, and on each side of the front. Epistoma convex, 

 beset with yellow bristles. Palpi clothed with long black hairs. First 

 and second and the base of the third joint of the antennae clothed 

 with black hairs. Thorax with 2 whitish stripes on the back, and with 

 an oblique yellowish white stripe on each side. Wings blackish ; discs 

 of the areolets paler towards the tips and along the hind border ; veins 

 black. Halteres yellow. Legs red, clothed with short tawny hairs ; 

 tibiae and tarsi armed with tawny spines ; tarsi and tips of the tibise 

 black ; claws tawny, with black tips ; onychia yellow. 



Generally distributed. (E. S.) 



2. cothurnata, Mg. zw. ii. 244. 6 (1820). Meigenii, Sd. ent. 

 141. 26. Atra, thorace cinereo-trivittato, lateribus abdominisque seg- 

 mentorum marginibus posticis ferrugineis, alis limpidis, pedibus fulvis, 

 tibiis apices versus tarsisque piceis. Long. 7-j ; alar. 1 3 lin. 



