NOTES AND LITERATURE 



EXPERIMENTAL EVOLUTION 

 The Effect of the Environment upon Animals. — The second vol- 

 ume of Bachmetjew's great work, "Experimented Entomo- 

 logische Studien" (1), will be welcomed by all who are inter- 

 ested in the effect of external factors upon organisms. It will 

 doubtless surprise many that, although dealing almost ex- 

 clusively with insects, the author reviews more than 1,200 

 papers. Even so, seasonal dimorphism, protective coloration 

 mimicry and parthenogenesis are only touched upon inci- 

 dentally as it is intended to take them up in a later volume. 

 Furthermore, practically none of the literature since 1905 is 

 included. The first 600 pages of the book are taken up with 

 short abstracts arranged in chronological order within appro- 

 priate groupings. These abstracts are then rearranged — often 

 being repeated verbatim — in the "theoretical part" according 

 to their bearing upon special problems. Although the author 

 states his opinions concerning the significance of the data thus 

 brought together, the reader is largely left to draw his own 

 deductions, as it seems to have been the aim of the author to 

 make a handbook to the literature of experimental entomology 

 rather than a dissertation in support of his own views. There 

 can be little room for doubt in view of this immense amount of 

 evidence that environmental factors are responsible for many— 

 perhaps most — of the variations and aberrations among insects. 

 However, there is, as yet, little proof that they produce heritable 

 modifications such as we believe real species to be made of. In 

 this regard Tower's work with Leptinotarsa is a remarkable ex- 

 ception. Practically all the results so far obtained, while inter- 

 esting and important, belong to physiology rather than to 

 evolution. 



Federly is continuing his work concerning the effect of ex- 

 ternal conditions upon the scales of Lepidoptera. A recent paper 

 (2) reviews the literature of albinism and gives certain original 

 observations. True albinism seems to be rare. However, cases 

 of ' ' pseudo-albinism. ' ' due to a reduction in the size of the scales 

 but not in the intensity of the pigment nor in the number of 

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