RECENT LITERATURE. 143 



great and lasting service to the cause of science. Dr. Standfuss's 

 experiments, the main results of which are illustrated by a series of 

 excellent coloured plates, some of which reach a very high standard 

 of beauty and accuracy, are chiefly concerned with the subjects of 

 hybridisation and of the alterations produced in the perfect form of 

 insects by the exposure of their immature stages to abnormal physical 

 conditions, mainly those of temperature. There can be no two 

 opinions as to the industry and thoroughness with which the author 

 has addressed himself to the task, nor will there be any question that 

 the results he has obtained and recorded are in the highest degree in- 

 teresting and valuable. It is equally certain, however, that his inter- 

 pretations of the facts will be in many quarters vigorously called in 

 question, as will appear when we mention that he upholds the doctrine 

 of the transmission of acquired characters (pp. 336-344), and that he 

 is disposed to minimise the value of natural selection in species-forma- 

 tion (pp. 286-292, 3). It would be beside our present purpose to enter 

 into a criticism of our author's views on these points ; we will simply 

 content ourselves with remarking that he does not seem to us to have 

 shown that the characters impressed upon individuals by direct action 

 of the environment are capable of transmission, unless in the limited 

 sense allowed by Weismann (' The Germ Plasm,' 1893, p. 401), which, 

 strictly speaking, does not involve heredity at all. We may say also 

 in passing that we cannot help thinking that a careful consideration of 

 the phenomena of insect-life in other regions than the palaearctic — say 

 the neotropical — would lead him to adopt a somewhat more sympa- 

 thetic attitude towards the question of mimicry than that expressed on 

 pages 295, 296. Be this as it may, the experimental portions of the 

 work form a storehouse of valuable material ; and the author certainly 

 deals fairly with his readers by presenting the evidence he has collected 

 in a full and unmutilated condition. • 



English entomologists will be pleased to find that Dr. Standfuss 

 cordially recognises the value of the work of Mr. Merrifield, much of 

 which in many respects anticipated his own. The remarkable results 

 obtained in this country by the last-named investigator with various 

 members of the genus Vanessa and other Lepidoptera by exposure in 

 the pupal stage to abnormal conditions of temperature, were unknown 

 to Dr. Standfuss until the close of his own experiments ; and the fact 

 that the independent descriptions by each author of the effects pro- 

 duced are so closely correspondent, forcibly testifies to the accuracy 

 of the observations of both. 



We note that Dr. Standfuss, though he is firmly convinced that 

 both heat and cold are capable, in different species, of inducing 

 reversion, does not allow that this result may follow the application 

 of either heat or cold in the same species. Eeasons for thinking that, 

 in some cases at any rate, the changes produced in the same species by 

 both raising and lowering the temperature are reversionary, have been 

 put forward by the present writer ; and Dr. Standfuss does not give 

 us his grounds for declining to accept them. The author's speculative 

 views as to the phylogenetic and distributional history of the Vanessas 

 and other groups are always interesting, and often convincing. 



The practical portions of the work, which are in most respects a 

 reissue of the author's former ' Handbuch fiir Sammler der europaischen 



