1892. 



THE BRITISH NATURALIST. 



easily seen mottled shells are devoured with the grass. It is evidently 

 assumed that the varieties breed true, at least to some extent, although 

 no statement of this kind is made. These remarks are followed up 

 by the suggestion that H caperata had originally a uniformly brown 

 shell. "We can imagine that the developement which the colouring 

 and marking have passed througli represent to us a gradual change, 

 through mottled forms, from an original form which had an uniform.ly 

 brown shell, which tends, owing to the surroundings of an arid, open, 

 and sunny habitat, to a uniform whitish or vvhite shell, which v/e know 

 is the prevailing characteristic colour of species living in dry and 

 sunburnt countries." "The variety ornata being really an aside form, 

 so to speak, prominent only on the sheep pastures, arises from the 

 causes previously explained." It is further suggested that the typical 

 forms of H, vivgata, H. encitonim, the var. bizona of H . acuta, and 

 kindred form of continental Helices may owe their prevalence to a 

 like cause. The geneology of the colour varieties of H. 

 caperata is summed up as follows, i. The brown shell: now 

 perhaps represented by the var. fulva, a reversion to the type 

 from No. 2 or No. 3. 2. Form with paler shades on brown shell 

 3. Ordinary mottled form and derivative forms, in which these 

 mottlings tend to produce bands (var. ornata.) 4. Forms in v\-hich 

 dark mottlings are disappearing. 5. Form from which mottlings and 

 bands have disappeared (var. albicans). Produced from No. 4, and 

 also from the var. ornata. No. 3. These forms in which the dark 

 mottling or banding is replaced by translucent markings may be 

 explained by the failure of the animal material, which is the basis of 

 the colouring matter of the shell. — W. A. Gain, Tuxford. 



THE PTEROPHORINA OF BRITAIN, 



BY J. W. TUTT, F.E.S. 

 (Continued from page 63). 



striking as in my series of Platyptilia gonodactyla, also from various 

 English localities. Mimceseoptilns plagiodactylus I have bred from 

 larvae feeding on, and partly in, the shoots of Scabiosa. These were 

 sent me by ^Ir. Purdey, of Folkestone. Previous to this Mr. Gregson 

 had been good enough to send me larvae of plagiodactylus, or as he 

 named it scahiodactylus. In his note accompanying the larvae, ^Ix. 

 Gregson wrote : — ' You will see how" distinct it is from plagiodactylus 

 of our list, which has a larva having a broad claret dorsal line.' The 

 body-colour and ornamentation of Mr. Gregson's larvae may be briefly 

 described thus : — Whitish-green, dorsal stripe reddish-pink (or rose- 



