189ri.] 211 



24. Peeicoma advena, Etn. 



P. aduena, ante, 2nd ser., vol. iv, 127, step 8, and vol. v, pi. iii, 

 P. 24. 



Referring to the original diagnosis — the rows of bristling hair, except on the 

 mediastinal nervure, extend beyond the dark transverse band (which externally 

 touches the bases of both of the forks, and is linked along the prsebrachial nervure 

 to the dark apical space), and beyond the dark spot on the axillar nervure, and end 

 in the whitish fascia and whitish spot. The wing-fringes are glossed with light 

 satiny drab, and the tuft at the base of the costa is slightly brownish at the roots of 

 the hairs j from certain standpoints the costal fringe matches (at least in parts) with 

 the darker portions af tlie disc. Beneath the wing, the scales and flattened hairs 

 have much the same distribution as in P. consors (22). Legs of a uniformly light 

 brownish colour, glossed with a lighter yellowish whitey-brown. Pubescence of the 

 head and upper surface of the body whitey-brown, glossed with impure whitish. 

 Supenor $ genital appendages of a similar pattern to those of the other described 

 species of this Section. 



The specimen remains unique. 



Section IV of Pericoma ; British species, Nos. 26—30 ; 

 Algerian, Nos. XIV, XV. 



Eefer ante, 2nd ser , vol. iv, 33, step. 6, and pp. 127 — 9 ; also 

 vol. V, pi. iii, P. 26—30 (details). 



Affinities chiefly with the preceding Section, but partly with 

 Section V and PsycJioda, Section II. Thus, in Subsection A, Pericoma 

 ustulata (27) and fratercula (26) respectively march well in touch 

 with P. decipiens (III, D, 20) and amhigua (III, C, 19) ; in Subsection 

 B, P. caliginosa (28), and the Algerian No. XIV, scheduled f B, supply 

 a natural link between the preceding species, via No. 26, and the 

 subsequent species of this Section, and more generally between 

 narrow-winged forms of Pericoma and the broad-winged species of 

 Section V ; P. incerta (29), scheduled f B.B., has closer affinity with 

 the remaining species, Nos. XV and 30, and with Pericoma, III, E, 

 than with Section V. Of the two species scheduled IV, B, ft, the 

 Algerian No. XV, like P. incerta (29), approaches the Algerian No. 

 Xil, scheduled Pericoma, III, E, e. ; the other, P. revisenda (30), while 

 sharing the same i-elationship, and while leaning towards the Algerian 

 No. XIII, scheduled Pericoma, III, E, e.e., in respect of the reduced 

 amount of bristling hair on the pobrachial nervure, constitutes a type 

 of Pericoma, approximate to Psychoda humeralis (6). 



{To be continued). 



