ISTX 41 



an effectual bar to migration has little to substantiate it, as many well accredited 

 instances are on record of the observation in mid-cUannel of species far less capable 

 of long sustained flight than T^. Antiopa, and migratory swarms of V. cardui have 

 been repeatedly noticed both here and abroad, as may be remembered by most of us. 



One fact has, however, apparently escaped consideration, tending to throw much 

 light on the vexed question, viz., the habits of the genus Vanessa under hibernation. 



It is well known that all the species of which a genus is composed share, in a 

 greater or less degree, any peculiar habit, especially amongst allied species ; and I 

 may here quote the remarks of M. Boisduval, one of the greatest entomologists of the 

 present century, and one who was too correct an observer to make a statement of 

 this description without due investigation. In his Introduction to the ' Species 

 general des Lepidopteres ' (Suites a Buffon), Tom. 1, p. 29, he says : — " Quelques, 

 " unes de nos' Vanessa europeennes, et, a ce que nous soup9onnons, plusieurs Hetero- 

 " ceres, presentent dans certains cas ime anomalie des plus remarquables : leur accou- 

 " plementji'a lieu que sept ou Imit mois apres I'eclosion de I'insecte parfait. Ainsi, 

 " par example, les Vanessa Antiopa, polychloros, &c., qui vivent en famiUe k I'etat 

 " de chenille, et qui eelosent en ete, ne s'accouplent que I'annee suivant au printemps. 

 " La plus grande partie continue de voler jusqu' a la fin de son existence, tandis 

 "qu'une autre se retire dans les crevasses des murailles, les arbres creux, les souterrains, 

 " les caves, et tombe dans uu engourdissement lethargique jusqu' aux premiers beaux 

 " jours. Quelques auteurs ont cm que c'etaient des iudividus tardifs qui avaient 

 " ete surpris par rapproche de la mauvaise saison et qui s'engourdissaient ; mais 

 " il n'est pas ainsi, nons avons eu occasion d'observer des Vanessa polychloros et 

 " wrticce, au mois d'aout, dans un engourdissement profond, pendant que d'autres 

 " individus des memes especes volaient a I'ardeur du soleil. Cest ce qui explique 

 " pourquoi on trouve au printemps des Vanessa qui sont assez fraiches, quoique 

 " toutefois leurs couleurs aient perdu im pen de leur vivacite par rhibernation."* 



Now as V. Antiopa is closely allied to V. polycliloros in habits, &c., we may 

 infer that the peculiarity is common to both of them, as the specimens of the former 

 captured in this country in spring, and which we may fairly suppose to be bred 

 here, are not more imperfect than those of the latter, notwithstanding Antiopa is a 

 moi'e delicate insect than polycliloros, and as such more liable to dilapidation. 



We have here a means of testing the value of the respective theories, for, should 

 V. Antiopa appear this spring in much greater numbers than in former years, we may 

 reasonably admit their claim to having been bred here ; but, on the other hand, should 

 only a few occur as in ordinary seasons, I think we mmy correctly regard them as a 

 foreign importation, as I conclude the greater number appearing in the spring to be 

 those which have commenced their hibernation soon after emerging from the pupa, 

 and therefore unlikely to be subject to the unknown influences which promote 

 migration. 



I may remark "en passant" that polychloros and ttrlicce have been observed as 

 commonly as usual this season, apparently little affected by the cold weather, or from 

 the mild winter decreasing their numbers through imperfect hibernation. — C. Fenn, 

 Ashley House, Eltham Road, Lee, S.E. : May 20th, 1873. 



»0n this point see also the observations made by Mr. Ban-ett in the autumn of 3S65, on speci- 

 mens of Vanessa urticte, which had taken up their quarters fur liibernation as early as August 

 11th, although for two months afterwards the weather remained hot and sunny, and F. urtiece 

 was flvmg about in profu.siou.— £nt. Mo. M..g., Vol. ii, p. 190.— Eds. 



