Franck: Aberrations in Lepidoptera 153 



produced totally different results. While a well-fed specimen 

 was more thickly scaled, darker and richer in color, etc., one 

 that was underfed was lighter in color and thinly scaled. 



Many other experiments of European entomologists could be 

 cited, as for instance, with plants subjected to aniline dyes and 

 other abnormal solutions. These experiments have been tried 

 repeatedly without any tangible results. The few instances I 

 have cited, will, however, suffice for the present. I cannot say 

 that I am satisfied with the results attained by this school. In 

 their work the speculative element is predominant and the facts 

 are not conclusive. 



Let us now consider the other faction or school, which claims 

 that aberrations are the result of climatic conditions. The work 

 of Dr. Standfuss shows the most remarkable results. By sub- 

 jecting the pupae of various species of Vanessa to different de- 

 grees of heat, he obtained a regular series of aberrations in V . io. 

 He recorded series of hundreds of specimens showing variation, 

 some without eye spots, others showing partial suppression of 

 the latter, etc., and some nearly producing the stem form of V . 

 ■urticco, showing undoubtedly that all these nearly related species 

 can be traced back to one primitive form, similar to V. urticce, 

 which in the course of thousands of years of gradual evolution 

 has produced the now distinct species of io, polychloros, xantho- 

 melas and others. V. antiopa is also a species that is very 

 likely to show excellent results of this kind, as large series of 

 aberrations, due to subjecting the pupae to both heat and cold 

 are known to exist. Strange to say, the results of Dr. Standfuss 

 were almost identical, although all specimens under my personal 

 observation could be easily traced to the medium which produced 

 the aberrant forms, viz., heat or cold, the individuals subjected 

 to cold being thinner scaled. Dr. Standfuss has proved, beyond 

 a doubt, that a certain percentage of heat or cold will result in 

 certain definite variations, and has named a number of varieties 

 or forms, which are, so to speak, manufactured to order. This 

 is a remarkable achievement in science and goes far toward 

 proving his ideas correct. 



