1895.] 2-17 



the ncrvures at the terminal margin, in both species, are often white 

 streaks pointing forwards along the edge. 



A local species found in proximity to the sources of feeble 

 streamlets among Apium {Heliosciadium) nodijlorum, and on hazel or 

 SnlLv cnpren, &c., April and May. 



12. Pericoma gracilis, Etii. 

 P. gracilis, ante, 2nd ser., vol. iv, p. 123 ; vol. v, pi. ii, P. 12 

 (neuration). 



This species was referred, in the Synopsis, to the 2nd Section of Pericoma, on 

 account of the junction of the poetical and anal nervures being situated nearly as 

 far beyond the posterior basal cell as the cell's apical width. Ilaving regard, 

 however, to the pattern of the bristling hair on the wings, it should rank in the 1st 

 Section ; the form of the superior J genital appendages consigns it to the Ist 

 Division ; and its hinder tibia) having blackish hair at the tips place it beside 

 P. palustris. 



Antennfe and palpi as in P. palustris ; the hairs white, glossed with light grey; 

 Ist joint in palpus short ; 2nd longer and subequal to the 3rd ; 4th longer and more 

 slender. Pubescence snowy-white in the ^ on the head and fore part of the thorax, 

 light grey between the wings, and white on the abdomen. Tn the same sex, anterior 

 to the tegulse and on the site of the pupal spiracle, is a small whitish thickened 

 circular disc covered over by a rounded tuft of arched white hair. 



A common species, beginning to appear at the end of April. 

 Obtained in Scotland at Lake Maree by Mr. J. J. F. X. King (4 J', 

 5 ? ; June and July, 1890). 



2. Pericoma mutua, Etn. 

 P. mutua, ante, 2nd ser., vol. iv, 121 ; vol. v, pi. i, P. 2 and la 

 (details). 



The small extent of the light-coloured gloss on the fringe at the wing's apex 

 aids in recognition of this species in the net, wliere otherwise it might be mistaken 

 for U lomyia fuliginosa, or another similar species of Pericoma, on account of their 

 close resemblance in coloration and markings to each other. Compared with 

 P. palustris and gracilis, there is less whitish hair on the wing ; in them, on the 

 axillar nervure, exterior to the fold of deflection, the bristling hairs arc spaced with 

 white, black, and white again, before the terminal outspreading black hair spot ; in 

 mutua, on the same nervure, the bristling hairs are blackish almost from the fold to 

 the whitish spot at their outer limit preceding the terminal outspreading blackish 

 hair. The dark fascioe of the wing are of a nearly evenly diffused depth of tint, tlio 

 densest hairs not constituting spots in proximity to the forks. 



3. Pericoma cognata, Etn. 

 P. cognnta, ante, 2nd ser., vol. iv, p. 121 ; vol. v, pi. i, P. 3 

 (neuration). 



