1908.] 251 



in my many store-boxes full of acquisitions resulted in my finding 

 three old examples, two of which had stood in the Burney collection, 

 and one in the S. Stevens collection, among the irrorellus : their 

 history is unknown to me, but they are obviously of British origin. 

 The specimens from the above-mentioned four sources agree well with 

 Hubner's figure of "rorrella" (fig. 231), and are beyond all doubt 

 specifically identical with those forming the beautiful series of rorellus 

 in the Frey and the Stainton continental collections, with which I 

 compared them last autumn. The insect must, I think, be very rare, 

 as a rule, in this country, and the six examples already referred to 

 are the only extant British ones that are known to me, nor are any 

 included in the sets of allied species in the national British collection. 

 Neither Mr. Vine nor I have seen it again, and unfortunately the 

 orchard grouud, which was opposite the above-mentioned wall, and in 

 which my friend thinks it highly probable that the moths observed in 

 1S95 had been bred, was soon afterwards built over. 



Yponomeuta padellus, L., or malinellns, Z., has been observed 

 over the English Channel during migration (Ent. liec.,xix,189 [1907]), 

 but the beautiful condition of all the specimens of rorellus that have, 

 to our knowledge, been noticed in Britain, seems to quite preclude 

 the idea of their having flown from any distance. 



Y. rorellus, 1Tb. (exp. alar. 25-26 mm.), need never be confused 

 with irrorellus, Hb. (exp. alar. 22-25 mm.), for its ground-colour is 

 whiter, its black spots are decidedly smaller, its grey cloud is fainter 

 and more extensive, and it has no large dark spot on the fold. Its 

 much larger size is, of itself, sufficient to separate it from the grey- 

 clouded white forms of padellus, L. {exp. alar. 17-20 mm.), which it 

 otherwise closely resembles in general facies, as also in the size and 

 position of the black spots. In rorellus, moreover, the grey longitu- 

 dinal cloud extends just below, but does not embrace, the posterior 

 half of the costa, whereas, when padellus shows a similar grey cloud, 

 this envelops the corresponding portion of the costa. 



Continental authors appear to be agreed that the larva of rorellus 

 feeds in May and June upon sallow, various collectors having found 

 it upon Salix alba, while S. caprea and helix are mentioned, on Hart- 

 mann's authority, by Sorhagen (Kleinschmet. d. M. Brand., 1G3 [1886]), 

 and according to Bossier, as quoted by Kaltenbach in Pflanz. Klas. 

 Insek., 169 (1874), plum must be its food-plant at Darmstadt. 

 Treitschke (Schmet. Eur., ix, 1, 222 [1832]) and Kaltenbach (op. cit., 

 pp. 574-5) give Kollar as responsible for the statement that the insect 



