158 THE entomologist's record. 



Weismann further says that we " are not helped here by the 

 assumption of purely internal forces which Nageli, Askenasy, and 

 others have put forward as supplying a mechanical force of evolution. 

 " It is," he says, " impossible to regard the coincidence of an Indian 

 butterfly with the leaf of a tree now growing in an Indian forest as 

 fortuitous, as a lusiis natwcw ;" but, although we arrive at the same 

 conclusion as Weismann, that selection has been the directive force 

 which has produced the markings, we do so on other grounds than 

 those by means of which he reaches this resiilt. It may, as he says, 

 be necessary to assume " pre-established harmony between the evolu- 

 tion of the ancestral line of the tree with its pre-figurative leaf, and 

 that of the butterfly with its imitating wing," if we are to assume the 

 directive force from within ; but does not the true explanation really 

 amount to this, that internal forces originate all these possibilities ; 

 whilst selection directs them into their several channels ? Thus far, 

 i.e., considering selection as a directive agent, we agree with Weis- 

 mann, that " cases exist wherein all natural explanations than that of 

 selection fail us," but considered as a creative agent (any further than 

 is assumed in its power to modify by direction) we doubt whether 

 Weismann's illustrations prove anything. 



Notes on the deviations in the Life= Histories of Bombyx quercus 



and B. caliunas. 



By Capt. B. BLAYDES THOMPSON. 



(Continued from p. 128y. 



We may now consider the synonymy of the species. To give some 

 idea of the entanglement in this respect of the species B. quercm and its 

 variety, a correspondent of Tlw Entomolotiist (vol. xii., p. 272) makes 

 the following apposite inquiries: — "Newman describes and figures 

 quercus, and simply mentions calhinae as a variety. Kirby calls 

 Newman's querem—mllunae, and makes no mention of roboris. 

 Staudinger, in his 1861 (Jataloi/iie, gives one species, qnerni.s, with ab. 

 roboris and var. callunae, the later (1871) Catakujue changing to var. 

 roboris and ab. callunae. Doubleday, in his Cataloi/m', 2nd (and last) 

 ed., 1866, makes roboris a var. oiB. quercus, and B. callunae & separate 

 species, and in his 1873 supplement he makes callunae a synonym 

 of B. quercus, and B. roboris a separate species, with B. quercus as a 

 synonym. Mr. South, in his List, gives only one species, r/c, B. quercus, 

 with callunae and roboris as varieties." Then the correspondent 

 inquires, " Is the species figured by Newman, quercus, callunae or 

 roboris ! If it is quercus, what are the distinctions between it and 

 callunae and roboris, and are the two latter natives of Britain ?" 



These queries were put to the editor of Tlie Entoviolo(/ist, Mr. 

 South, by a lady, and he replied: — "As regards callunae. Palmer, 

 and roboris, Schrank, the two varieties found in Great Britain, 

 authors do not seem quite in accord. I apprehend that quercus, 

 L.S.N., \., 498, is the type form most generally distributed in Europe, 

 including England, callunae the form which occurs in moorland 

 and mountainous districts, and differs from the type, principally in 

 the darker colour of the female ; and roboris, a variety of the male, 

 which has the fulvous bars of the fore-wings wider than usual, and 



