UACcir.v. 



113 



Genus BACCHA, Fair. 



Baccha, Fabricius, Syst. AntLj). 199 (1805). 



liacca, Koudani, Dipt. Ital. Prod, ii, p. 104 (1857). 



Bacha, Scliiiier, Faun. Austr. i, p. 32.'> (1862). 



Bacehina, Williston, Mon. N. Amer. Dipt. 2iid Ed. p. 86 (1896). 



Genotype, Stirplms eJonqatus, Fabr. ; by designation of Curtis, 

 Brit. Ent. (1S39). 



Head more than hemisjjherical, broader than thorax, tiat^;ened 

 behind: frons slightly prominent; eyes bare, contiguous for a 

 long distance in 6 , narrowly separated in $ ; antennte short, 3rd 

 joint deeper than long, arista bare. Face generally swollen in 

 centre, the swelling forming an indefinite bump, or with a small 

 distinct tubercle. Thorax and scutellum normal, former much 

 wider across the middle. Abdomen very slender, very much 

 longer than thorax, 2iid and 3rd segments very long and narrow, 

 behind which the abdomen widens gradually nearly to tip. Some 

 pubescence at sides of abdomen on basal half. Legs long, thin. 



Fig. 20. — Baccha triavgulifera, Aust. {elegans, Brun.), (f . 



simple; hind femora distinctly lengthened but not thickened; 

 basal joint of hind tarsi generally thickened. Wings with vena- 

 tion of Sijrphus; alula very small or almost absent; squamio 

 small, inconspicuous ; wings at rest folded over abdomen. 



Very slender, graceful ilies of moderate size, fond of hovering ; 

 the species somewiiat didicult to separate. 



Life-Jiistorif. Larv:e feeding on Aph'ido', or perhaps Coccido:. 



llancje. Practically world-wide. 



The exact generic limits of Baccha are not very definite. Some 

 authors include in it Ociqttamits, a North American group, whil>t 

 Major Austen seems to have much extended the scope of the 

 genus. The 2nd segment of the abdomen is sometimes almost 

 fused with the broader, very short 1st segment, and this must not 

 be lost sight of in interpreting the descriptions. 



