1890.] 



THE YOUNG NATURALIST. 



79 



THE PTEROPHORINA OF BRITAIN, 

 By J. W. Tutt, F.E.S. 

 Continued from page 20, Vol. XI. 



P. isodactylus. — This species is erroneously called the similidactylus 

 of Dale by Dr. Wocke in his ' Catalogue,' and hence it is called by 

 a different name on the continent, to the one in common use here. 

 The similidactylus of Dale is without doubt our lithodactylus . There is no 

 question, therefore, that the Continental nomenclature will have to be 

 brought into agreement with our own. The error of Dr. Wocke 

 does not seem to stop here, for he gives as synonyms : — Monodactylus, 

 Haw. p. 476, Stphs. 111., iv., 373, but Haworth's description : — 

 " Aluc alis anticis canis retusis, fissura inconspicua, posticis tripartitis 

 fuscis," does not appear to be referable to isodactylus. His further 

 description copied from Villars, makes it still more certain that 

 Haworth could not have intended his monodactylus to be the species 

 we know as isodactylus. 1 



Synonymy. — Isodactylus, Zell. Linn. Ent. Zeitschrift, vi., 328, 

 Stn. " Manual," ii., p. 440 ; Similidactylus, Std. Cat. (non Dale). 



Imago. — This species was first described by Zeller. His description 

 (" Linn. Ent. Zeitschrift," Vol. VI., p. 328) is as follows: "Alis anter- 

 "ioribus fusco ochraceis, antice obscuvioribus, triangulo costali ante fissuram 

 "obscuriove obsoletissimo ; in digiti tertii dovso medio squamis paucis atris 

 " (male musei Stainton J." 



Stainton in the " Manual " Vol. II., p. 440 describes the species 

 as : — " 10"' — • 11'" F.w. dull greyish ochreous clouded with darker, 

 with a very obscure costal triangle before the fissure ; tip of anterior 

 lobe not produced, scarcely pointed." The anterior wings are divided 

 into two lobes, the apex is comparatively blunt, and the ground colour 

 is pale greyish or ochreous-brown, more grey in the central area, with 

 a more or less distinctly defined triangular blotch placed on the costa 

 just before the fissure, between the lobes of the anterior wing ; the 

 outer margin darker than the ground-colour, the darker band being 

 followed by a paler line parallel to the outer margin, fringes pale 

 greyish. Posterior wings divided into three plumules, greyish-brown, 

 fringes paler ; the third plumule has some black scales, but not form- 

 ing so distinct a tuft as they do in gonodactyla. Head, thorax and 

 abdomen same colour as the ground colour of the wings. 



