Xo. 629] SHORTER ARTICLES AND CORRESPOXDEXCE 561 



GENETICS AND EVOLUTION IN LEPTINOTARSA 

 In considering work of the kind presented by Professor Tower 

 in his latest partial report on Evolution in Leptinotarsa (Tower, 

 1918) it is necessary, in justice to the author, that we distin- 

 guish carefully between three different things : the actual experi- 

 mental work, the author's interpretation of its results, and his 

 general speculations. Professor Tower had secured an unusually 

 favorable opportunity for attacking his problem, by a fortunate 

 selection of material. The "lineata" group of the genus Lepti- 

 notarsa comprises a large number of forms generally recognized 



habiting markedly dilVcrcnt tMiviroiinuMital complexes, and easily 

 bred in the laboratory. His wnrk ivp.vMMits a pro.ligioiis amount 

 of painstaking lal)()r. coxci-ino' many yeai-s. untiei' most favor- 

 able conditions. It will a -matter of regret to many that so 

 large a proportion of this volume lias been devoted to very gen- 

 eral speculation, rathei* than a more comj)lete presentation of 



firnmtion. hut nothing adih'd. In what we already know, i hough 



