7. PTIOLINA 313 



Barmouth and Porthcawl ; I suspect also that B. Cooke's record (Naturalist, 

 v., 134) of PtioUna mclama at Whaley-Bridge in Cheshire refers to this 

 species. The dates range from June 12 to 29. 



Synonyviy.—-li is very necessary to identify this species correctly, as upon its 

 determination many other names depend. The type of the genus is^ the species 

 which Zetterstedt (or Stagger) recognised as Leptis obscvra of Fallen. Fallen's 

 original description was as follows : 



"11. L.obscura grisescens, ahdomine pedihusque lividis ; nervo alarum postico 

 " angularem formante arcuato, crasso. 



" In Scania non nisi rarissime obvia. 



" Fem. Obscura, prascedentihus minor. Abdomen lividum, an in vivente flavo- 

 " maculatum ? Pedes obscuri.— Ab omnibus speciebus supra commemoratis satis 

 " distincta : nervo alarum illo postico, qui nervum format angidarem, ceteris 

 " crassiore et arcuatim flexo. 



"Mas." 



This description, though insufficient, is not contradictory to our British species, 

 and in itself fairly defines the genus PtioUna, but one must recognise that many 

 additional European species of Ptiolina are now known. The next writer who 

 knew the species — Meigen merely copied Fallen — was Zetterstedt, _ who was 

 intimately acquainted with Fallen's collection, and his description in Insecta 

 Lapponica under the genus Le2otis is perhaps worthy of being given in detail : 



" 7. L. obscura : nigra aut fusca, alis hyalinis, basi concoloribus, antennarum 

 " articulo primo brevi, ultimo ovato. S 9 • 



" Mas. : Totus niger immaculatus, subpilosus, alis f umato-hyalinis ; Fem. : Fusca 

 " aut griseo-fusca, parum pubescens, thorace subvittato ; alis hyalinis. 



" Var. a. S 9 • halteribus nigris. 



" Var. b. $ . halteribus albidis ; paullo major obscurior. 



"J/fls. et Fem. In hoc genere minima, vix ultra 2 lin. longa, de cetero hujus 

 " omnino subdivisionis. Mas. : niger, hirsutulus. Palpi erecti, Antennarum 

 " articulus ultimus ovalis, subcompressus, seta longitudine fere antennae, apicali. 

 '' Ociili viventis brunnei, vix seneo-micantes. Alaj tota3 obscure hyalinaj ; linea 

 " stigmaticali lata, obsoletissima. Area angularis conclusa, angulo acuto ad 

 " marginem interiorem non usque retracto, omnino ut in prioribus, sed areaj 

 " nervo superiori crassiori. Pedes toti nigri. Femina : obscura aut grisescens, parum 

 " pubescens. Thorax subvittatus. Alte hyalinai. Pedes_ obscure liyidi. _ De 

 " cetero omnia ut in mare. — Variat (? . duplo minor ; variat etiam alis albidis, 

 " nervis fuscis, stigmate nigro, quales in Dalekarlia a D. Boheman lectos vidi. ' 



There are numerous contradictory statements in this description which render 

 its identification with our species rather difficult when compared with subsequently 

 diiferentiated species. Under his diagnosis Zetterstedt says "alis hyalinis, basi 

 " concoloribus," but under his note of the male he says "alis fumato-hyalinis " and of 

 the female " alis hyalinis " ■ now in our British specimens the male has the wings 

 "fumato hyalinis" but the female has the wings by no means hyaline; this 

 character is however strongly modified by Zetterstedt later on in Dipt. Scand., 

 i., 227, when he says of both sexes " alis hyalinis, stigmate fusco ; halteribus albis, 

 clava obscura," and with a "Var. a. ^9. halterum clava nigricante" and "Var. 

 " b. ? , halterum clava alba ; " paullo major," then later on "Alaj cinereo-hyalinai, 

 " stigmate obscuriore. . . . Femina tota, etiam fronte lata, obscure cinerea, thorace 

 "subvittato." At that time no other species of the genus was _ recognised except 

 ^etterstedt's new species P. nigra, which (from subsequent descriptions) was easily 

 distinguishaljle by its strongly pilose basal antennal joints but which included 

 under its description an allied species P. nigrina Whlbg. This was written in 

 1842, but in 1854 Wahlberg dealt with four species known to him, and while 

 P. nigra (= atra) and P. nigrina are well distinguished from all known European 

 species by the long and densely pilose basal antennal joints, and P. nitida by the 

 brilliantly shining vertex of at least the female, P. obscura is described in words 

 absolutely fitting our British species, such as "epistomate et basi antennarum 

 " pilis raris brevibus munitis, . . . thorace obsolete fusco-3-lineatp (? ),_ ._ . . alis 

 " dilute fuscescentibus stigmate saturatiori, . . . Femina antennis basi interdup 

 " subferrugineis." I cannot doubt but that our British species was included in 

 Wahlberg's description of P. obscura, and therefore I adopt that name for it. 



I 



