NOTES AND OBSERVATIONS. 293 



49. suri, Hausm., Illiger Mag. vi. 1807, p. 244. 



cafer, Serv., Encycl. Meth. x. 1825, p. 351. 

 capensis, Dej., Cat. 3rd ed. p. 150. 

 hottentotus, McLeay, Horas Ent. i. 2, p. 498. 

 laicus, Illiger MS. 

 3.— Cape Colony ; Cape of Good Hope ; Port Elizabeth; Natal. 

 In Mus. Hope. 



(To be continued.) 



NOTES AND OBSERVATIONS. 



The Vertical Distribution of Pieris rap.e. — I was always under the 

 impression until recently that this butterfly was a lowland species, only 

 being found in cultivated parts. I have, however, met with it this summer 

 in the Grindelwald, at an elevation of nearly 7000 feet above the sea- 

 level, which is well within the upper alpine zone of Speyer ; while in the 

 pine or lower alpine belt, some 1000 or 1500 feet lower, it was exceed- 

 ingly plentiful. As I could find no trace of any cruciferous plant which 

 could constitute the pabulum of its larva in either zone, I conclude that 

 the insect does not permanently reside at such an elevation, but only 

 occurs there in the winged state. Will any readers kindly inform me 

 what is the greatest elevation at which they have observed this butter- 

 fly in the British Isles ? My experience is that it is an exclusively 

 lowland species, not occurring above the altitude of 1000 feet further 

 north than latitude 52^. — W. Harcourt Bath ; Ladywood, Birming- 

 ham, Sept. 14th, 1894. 



Zygjena trifolii ab. — In Mr. South's short notice {ante, p. 253) of 

 the capture of a curious aberration of Zygana trifolii by Mr. W. M. 

 Christy, no mention is made of the condition of the legs. As there are 

 two cases on record (' Materials for Study of Variation,' by W. Bateson, 

 p. 148), one, of the replacement of a leg by a wing, and the other of the 

 reverse phenomenon (although apparently neither seems fully substan- 

 tiated), some further description relative to such points would, I feel 

 sure, be welcomed by all students of variation. From the figure of the 

 specimen I judge that the last pair of legs (at least) is normal ; if so, 

 it would seem that, for some reason, the development of the dorsal pair 

 of metathoracic imaginal discs was arrested, and that an attempt had 

 been made to supply their place by division of the dorsal meso- 

 thoracic disc of one side. Of course this is pure surmise, and some 

 people may argue that it merely shifts the responsibility of an explanation 

 farther back in the life-history, and that the changes suggested are as 

 difficult to understand the reason of as the phenomenon itself; if so, 

 the question must be an individual one ; but it does seem to me to 

 account, in however imperfect a manner, for that correlation of 

 variations, the occurrence of which, considering the extreme rarity of 

 all variations involving absence or reduplication of appendages, can 

 hardly be attributed to chance. For, suppose, in the absence of 

 statistics, that the probability of one such variation is 1 in 1000, and 



ENTOM, — OCT. 1894. 2 A 



