~i^ Heredity and Eugenics 



parallel bands. A double-striped condition in place of a 

 single stripe. 



Many of the mid-tj-pes exhibited the same modifica- 

 tion to a lesser degree, especially the break in the band. 

 A female of this double-striped character was ms,ted with 

 an extracted male iindecimUncata (a brother), and when in- 

 bred there were obtained in the next generation adults with 

 the elytral stripe single, the elytra! stripes single and broken, 

 double, double and broken. From these it has been pos- 

 sible, by a process of analysis, to develop the following stable 

 combination : a t^'pe in which the larva is white with large 

 black spots upon the back like the larva of signaticollis , but 

 with the ground color white, and with the elytral stripes 

 double in the adult; the same type with the stripes double 

 and broken, and the same type but with the ramous and 

 first costal stripes also broken. Third, the same t}q)e of 

 larvae, but with all of the stripes broken. The elytral 

 stripes are extremely invariable and most diffrcult of modi- 

 fication, but this example shows clearly that by combining 

 in the process of hybridization characters accentuated by 

 selection — and it will probably be true of characters accen- 

 tuated in any other way — that there is a definite increase 

 in the modification of characters and that they are rendered 

 stable in the constitution of the gamete and might easily 

 take part in the formation of species. Figs. ']6A-G show 

 some of the t}pes thus far obtained from an evolution 

 movement initiated by the process described. 



In these experiments the modifications are in no wise 

 due to the influence of external factors; in fact, they were 

 carried out under relatively constant conditions, nor is it 

 conceivable that external factors could be productive of such 

 a result. What it is that has brought about these modifica- 



