1895.] 245 



SUPPLEMENT TO "A SYNOPSIS OF BRITISH PSYCH0DID2E," 



BY THE KEY. A. E. EATON, M.A., F.E.S. 

 C Continued from page 213). 



Peeicoma (Haliday, MS.), Walker (1850), part. 



Syn. Psychoda, section B (Hal., MS.), Curtis, Brit. Eat., 745 

 (18:i9).— Pmcowa (Hal., MS.), Walk., Ins. Brit. Dipt., vol. iii, 254 

 and 256 (excl. sp. Noa. 1 and 3) ; Schiner, Ins. Aust. Dipt., ii, G32 ; 

 Van der Wulp, Dipt. Neerlaud., i. 



The two species eliminated from the genus as originally consti- 

 tuted in Walker's work, appertained to the genus Psychoda as 

 restricted (Hal., MS.) in the same volume. After their removal, 

 Pericoma remained an assemblage of species of miscellaneous affinities, 

 distinguished from TJlomyia by having no pouches in the wings of the 

 males, Avhile some, more closely related to Psychoda, differed from this 

 last genus mainly in having numerous instead of few tenacular 

 spiiiules on the inferior genital appendages of the males. Beyond 

 increasing the number of described species, the Synopsis made no 

 material change in the constitution of Pericoina ; but by strengthening 

 their representation, it caused the plurality of types included under 

 this name to be clearly manifest. The Sections into which the British 

 species were assorted in 1893 were not of equal systematic value, and 

 cannot all rank as Sub-genera ; and the further synoptical grading of 

 the species was devised more with a view to their being easily identified 

 than to their formal classification. 



The British species are numbered here as in the Synopsis, to show 

 their original sequence and to facilitate reference ; and in Sections II 

 — IV the supplementary or other principal characters employed in 

 the revised classification are stated in tabular form for greater con- 

 venience. 



Section I op Pekicoma ; British species, Nos. 1 — 7 and 12 ; 

 Algerian, No. I. 



Affinities with Ulomyia and Section II of Pericoma. 

 Refer ante, 2nd ser., vol. iv, p. 32, step 4« ; pp. 120-1 and (No. 

 12) 123 ; vol. V, pis. i and ii, figs. P. 1-7 and 12 (details). 



Wing : broadly-ovate ; apex rounded at or very close to the end of the cubitus. 

 In most species the postical meets the anal nervure at its entrance into the lower 

 angle of the posterior basal cell : when they unite beyond the cell, their junction is 

 not farther from that angle than the cell's apical width. Bristling hair restricted to 

 the same primary and secondary nervures as in Ulomyia, and extended outwards 

 farthest either (as in that genus) on the anterior radius, or (sp. Nos. 6 and 7) sub- 



