6 THE entomologist's RECOftt). 



my having referred to inherited habits, morphological adaptations, 

 and acquired instincts as having acted as factors in the vital phenomena 

 of various animals. Now, it seems to me that either he must take the 

 position of denying that there are such things as those which go by 

 the above titles, or else that these inherited tendencies produce 

 results. As Dr. Dixey in his preceding sentence speaks of the 

 " hybernating habit," and as Professor Weismann frequently employs 

 the term " hereditary tendency," I presume that the existence of these 

 phenomena is unquestioned. But if natural selection by a longer or 

 shorter course of operations has given rise to a habit in any succession 

 of individuals, that habit, though only a result, becomes a factor, so 

 long as it survives, in controlling the actions of the organism ; and, 

 as I contended, in case of a change in the environment, before the 

 new conditions have had time to induce a full reaction, the old habit 

 would persist, and force the animal along the old groove, even to its 

 detriment. 



Now, if any results are produced by such instinct or habit, they 

 may either be trivial and transient, or. on the other hand, they may be 

 far-reaching and destructive of the race before adjustment to a 

 changed environment takes place. Take the case, even hypothetically, 

 of certain moths in the x\rctic regions, which are said to be attracted 

 by a bright light in the daytime, even as their fellows are in countries 

 where night gives them a signal for flight. This instinct, if the fact is 

 as I have mentioned, may be a survival from an earlier epoch, when 

 those regions were not in their present position in regard to the pole, 

 and were subject in part, at least, to alternations of day and night 

 during the period of their imaginal existence. Or take any other 

 hypothesis as to the origin of the instinct and its survival. One 

 observer has recorded that he noticed numerous specimens drowned in 

 the waters of a cascade, into the flashing sweep of which they 

 persistently flew. Natural selection in the end eradicates prejudicial 

 habits, if the animals survive during the period of that sometimes 

 very slow process, but, pending this, the secondary factor will con- 

 tinue to operate. Dr. Biding, whom I know to be an enthusiastic 

 worker and careful observer, agrees that possibly my theory of unreason- 

 able surviving habits may be a sufficient explanation of cases of 

 hybernation which commence before any cold or scarcity of food has 

 set in. He is mistaken in thinking that 1 deny the latter factor to be 

 a possible predisposing cause in the evolution of a hybernating habit. 

 My arguments were merely in support of the proposition that cold 

 was an original and potent factor in its phyletic origin, but I nowhere 

 negatived the other suggestion. In pointing out that cold produced 

 torpor, I mei'ely desired to suggest that torpidity was a somewhat 

 analogous phenomenon to hybernation, suggestive of homologous 

 adaptations, probably both physiological and morphological in a 

 similar direction. Dr, Dixey points out that the latter is physio- 

 logically different from the former. 



I am unfortunately ignorant of the researches of Mr. Marshall Hall 

 on this subject, and have no opportunity in the country to consult 

 them ; but torpidity would appear to be the direct efiect of cold upon 

 organisms not prepared to adjust themselves to the stress, while 

 hybernation may be the acquired method of adaptation in such cases 

 as are subject to regularly recurrent conditions of cold as obtain in 



