222 Isabel McCracken 



season no such freaks were found, and those bred in the laboratory 

 failed to mate, they were looked upon as representing possibly a 

 pathological condition. 



However, in 1905 outdoor scriptas were kept under constant 

 surveillance throughout the breeding season. At stated periods, 

 four or five weeks apart, several hours were spent in the field, at 

 which time several hundred individuals passed under inspection 

 with the following result: 



First inspection, March 4. Thousands of beetles in a limited 

 area feeding and beginning to breed. (These were in all proba- 

 bility the hibernated individuals from the previous year.) No 

 "all black" (AB) individuals were observed. Several hundred 

 individuals, representing each of the dichromatic extremes, were 

 collected at this time for indoor controlled breeding. 



April 12 : Many thousands of beetles observed; two AB females 

 collected. 



May 14: Many thousands observed, two AB females collected. 



June 21: Many thousands observed, two AB males collected, 



July 28: Individuals in this particular feeding ground becom- 

 ing noticeably fewer. Many hundreds of beetles observed, one 

 AB female collected. 



August 21 : Many hundreds of beetles observed, one AB male 

 collected. 



Hence a total of five females and three males were collected in 

 this locality during the five months the locality was under observa- 

 tion and covering the breeding season of the beetle. Three similar 

 sports were collected during this time from poplar trees a half mile 

 or so distant from this locality. 



During the progress of these outdoor inspections, indoor breed- 

 ing was in progress from the collection of March 4, 1905, that is, 

 a collection made up of "spotted" (S) (Fig. i) and "black" (B) 

 (Fig. 2) but no "all black" (AB). 



Four generations were reared to maturity from this collection. 

 The following table gives the data in regard to the occurrence 

 of the sport AB with the character of the lineage in each genera- 

 tion. (The term "sport" is here used in the sense of a singular 

 and decided variance from the normal type.) 



