OF ENVIRONMENT 125 



conclusions may be founded upon the evidence 

 obtained. The results of the work by Tower, in 

 which beetles of the genus Leptinotarsa were 

 subjected to various combinations and alterations 

 in climatic conditions in a series of experiments 

 carried on for a period of more than twelve years, 

 have recently been available and far surpass in 

 importance anything previously obtained from 

 animals. The value of the evidence is greatly 

 enhanced by its repetition, by the fact that pedi- 

 greed cultures were used and conditions so regu- 

 lated that an accurate analysis of the effects of 

 the various cUmatic factors could be made. 

 Professor Tower finds that : — 



" Not only members of the genus Leptinotarsa, but 

 also of allied genera can . be directly modified by the 

 application of intense environmental stimuli to the 

 germinal material. The use of temperature and 

 moisture in unusual degrees of intensity has given rise 

 to a number of forms and modified characters. Some 

 notion of the extent of these modifications is gained 

 from the two following illustrations. In Plate I, 

 Figure 1, is shown the normal form of L. vmdecvmlme- 

 ata, and in Figure 2, a race derived from it by the 

 application of low temperature and low relative humid- 

 ity. This new form resembles in some respects Jacoby's 

 species L. angustovittata, and breeds true. It matters 

 not whether this new form is a species, race, elementary 

 species, or a nightmare to the systematist, the important 

 point is, that as the result of subjecting the germinal 

 material to certain conditions at a fixed point in its 

 development, that the eggs thus treated, when fertihzed 

 by normal male germs, gave the form shown, which 

 breeds true without subsequent segregation of charac- 



