SCIENTIFIC NOTES. 91 



Suecicce, p. 370, "lonodactyla, pentadacfyia, and pterodactyla (fusais) are 

 fairly well-defined as British species, although I would point out that the 

 Linnaean description of monodactyla, Sy sterna Naturcc, loth edition, p 

 542 : "' Ahicita, alis patentibus linearis indivisis," is unsatisfactory, as 

 fir as the "indivisis" is concerned. But the description, "infer. ores 

 fere tripartitte," etc., in the Fauna SueciccB, p. 370, No. 1452, makes it 

 (juite clear that it cannot belong to the Agdistis group. 



(i). Didac/y/a, Linn. This species is happily settled and fully deter- 

 mined by its foodplant. Linnceus gives, Systenia Naturce, 12th edition, 

 p. 899 : " Habitat /// Geo rivali." Mr. Stainton, Eni. Mo. Mag., vol. i. 

 pp. 12-14, gives a full account of the plume in Geiun rivale — the 

 Alucita didactyla of LinnKus. This is not a British species, and there- 

 fore cannot be the didactyla of Haw., which I shall refer to again. 



(2). Telradactyla, Linn., and tridaciyla, Linn. ; fetradactyla, Haw., and 

 iridaciyla, Haw. About the species tetradactyla and tridactyla of 

 Linnaeus, there is, as Mr. Stainton pointed out {Ent. Mo. Mag., vol. i., 

 p. r2) some difficulty. The Linnaean species tetradactyla of the Fauna 

 Siiecicce, pp. 370-37 1, is without doubt the species we know by that name. 

 "Aire superiores lineares : linea albj, longitudinali, ut soli margines 

 obscuriores, immaculata. Pedes albi." The " linea alba " is most 

 characteristic of 1^ tetradactyla, but in the Sy sterna Natural, both loth 

 and 1 2th editions (loth, p. 542 ; 12th, p. 900), tetradactyla gets a fresh 

 description : " Alucita alis patentibus fissis flavescentibus," which fits 

 o ir species nowhere ; but to muddle matters, the tetradactyla descrip- 

 ti )n of the Fauna Sueciccc is applied to a new species tridactyla, and 

 therefore the tridactyla of the Systenia Naturip becomes synonymous with 

 tetradactyla of the Fauna Suecica;, both representing our ^ tetradactyla. 

 The difficulty now remains what is the tetradactyla of the Systenia 

 iVaturce ? The " flavescentibus " is the puzzle. It might refer to the 

 closely-allied baliodactylus, but this is not a Scandinavian species, and 

 therefore very improbable. It might be an entirely different species — 

 " osteodactylus,'" or some other — or finally, it may be that Linnaeus is 

 practically correct, and the tetradactyla of the Systenia Natures is the 

 $ of that species, as the ? is very different to the $, and is of an 

 uniform dirty yellowish-white colour. Haworth, in the Lepidoptera 

 Britannica, p. 477, uses the Linnjean diagnosis for tetradactyla from the 

 Fauna Suecicce, and afterwards adds the description {vide above) from 

 the same work, and which, as I have before said, is most distinctly our 

 tetradactyla. But we have to remember (as I have also pointed out) 

 that this species is sexually dimorphic, that the male has dark costal 

 and inner margins with a longitudinal white line, while the female 

 has the anterior wings entirely whitish. Linnaeus may have (as I have 

 previously stated) described the sexes as distinct ; Haworth, I think, 

 certainly did. Haworth (quoting Fabricius) describes tridactyla as : 

 " Alucita alis fissis ; anticis bifidis albis, posticis tripartitis fuscis, Fab.," 

 and then adds : " Parvus, distinctis alis anticis fissis totis albis, posticis 

 trifidis fuscis" {Lepidoptera Britannica, p. 477). This I consider a very 

 fair diagnosis of the female tetradactyla. 



(3). Tesseradactyla, Linn., and tesseradactyla. Haw. We now come to 

 another species, tesseradactyla. This species is given as British by 

 Haworth, but the species known on the Continent by this name is not 

 a British insect, the name being applied to a species closely allied to 



