266 Mr. C. G. Lamb on Exotic Helomyzldse, (Ssc. 



XX. — Notes on E.totic Helomyzldss, Sciomyzidns, and 

 Psilidse. By C. G. Lamb, M.A., B.Sc, Clare College, 

 Cambridge. 



Helomyzidae. 



Helomyza, Fall. 



In the Wiener Ent. Zeit. for 1904 Czerny critically 

 examined all the species of tiiis genus up to that date ; since 

 then only about half a dozen species have been added, and 

 hence the taslc of workin^;- out the specimens in the collections 

 was much simplified. There was one well-known species 

 and three new ones, one of the latter being very interesting 

 as departing from the almost universal character of having 

 extra costal bristles. 



Htlomyza plcta, Wied. 



S. Rhodesia: Chirinda Forest {G. A. K. Marshall, 

 Camb. Coll.). 



There was a fair series of this handsome insect. It 

 exhibits considerable sexual dimorphism. The sex described 

 is the male, and it has the dorsum elegantly variegated in 

 ochre and dark ochreous grey ; its femora are beautifully 

 and regularly spindle-shaped, the mid pair less so, and they 

 bear long dense hairs below. The female has a quite dark 

 dull brown dorsum and scutellum, which exhibit only faint 

 signs of the male marks ; the femora are normal, less haired, 

 and the front ones have an anterior spine row — in fact, the 

 sexual differences in the legs are like those of some Scato- 

 phagas. This type of Helomyza is devoid of the upper 

 patches carrying the orbital bristles, and also of the small 

 ocellar triangle joined to these, which are usual in the Euro- 

 pean forms; it has also pictured wings and swollen and hairy 

 male femora; this form seems to be typically African. 

 JSpeiser, in his Kilimandjaro-Meru Expedition paper, describes 

 two males of tiie same facies — //. acroleucac\.\\(\ II. lactnata — 

 and the next species also belongs to this section. 



Helomyza ingens, sp. n. 



A single male of the ptcia group was present ; it is larger 

 and more stoutly built than that species. 



Head (top view) : — Frons and antennas entirely yellow to 

 orange, in front a little darker^ with microscopic hairs and 



