178 THK CANADIAN ENTOMOLOGIST. 



impotent to create new races until an individual, no different externally 

 from the others, is found whose offspring do not revert as do offspring in 

 general. However, if, after a female, for instance, has attained her 

 final form and coloration, she be subjected to extreme temperature and 

 moisture conditions, the germ plasm of the eggs then maturing is so 

 affected that the beetles developing from them are, for the most part, 

 entirely different from the parent form, even though their entire ontogeny 

 is passed under perfectly normal conditions, and they will breed true, 

 under normal conditions, to their new characters. If this same original 

 female had been returned to a normal environment the eggs which mature 

 under these conditions develop into normal offspring as though their 

 mother had never been forced to give birth to abnormal children. To 

 quote part of a single experiment : 



" In May, igos, I subjected four males and four females from the hibernatingf 

 population of dccenilineafa to extremely hot (average 35' C), dry (relative 

 humidity, average 45 per cent.) conditions, accompanied by low atmospheric 

 pressure (19-21 inches) during the growth and fertilization of the first three lots ot 

 eggs, which were placed as soon as laid in natural conditions and reared. The 

 last two lots were laid and reared in normal conditions. The first I designated 

 Lot A, the second Lot R. All were reared during their ontogeny from the earliest 

 embryonic stage to adults in normal environment. From 506 larvai which hatched 

 from Lot A I obtained 96 adult beetles, of which 82 were of the form pallida, two 

 of the form imtnaciilo'tlnn-ax, and 14 unmodified. From Lot B, of 319 eggs I got 

 6t normal beetles.' 



In another experiment the action of abnormal conditions on the 

 forming germ plasm brought about inheritable physiological modifications. 

 They had five instead of two or three generations a year, being normal in 

 every other respect. This was kept up through three cycles, when the 

 experiment was stopped. "In the ns^ oi & five-brooded race i\\trt \\:\.s a 

 pure, perfectly constant inheritable character arising as the response to 

 stimuli applied to the germ plasm. Eleven years of study of this and 

 related genera have shown that /;/ tione of the family, or relations of the 

 family, are there traces of five-brooded races or species." 



Unfortunately, further details of the data can not be given here. But 

 an idea of the contents of the paper has perhaps been given. Not even 

 all the conclusions can be quoted. The following, however, can not be 

 passed over : "Variation is to be interpreted upon the basis of response to 

 stimuli directed by the stage of development reached and the nature of 

 the pre-existing stages. Variation is also epigenetic, and not a pre- 

 determined character in organisms " (^). 307). "There is not at present 



