the determination of dominance. 293 



Experiments in Analysis, 

 Crosses Between L. signaticollis and L. diver sa. 

 The first effort was to determine whether or not external or 

 incident conditions were in any way responsible for the produc- 

 tion of the diversity of behavior found. The first experiment 

 was a cross between a male L. diversa and a female L. signaticollis. 



L. signaticollis ^ X d' L. diversa. 

 Exp. No. H 409.^ 

 A virgin female of L. signaticollis, from Exp. No. 419, g. XI 

 (CCB) was mated with a male L. diversa, from Exp. No. 816, g. 

 VI (A), under the following conditions: 



Food : Normal — uniform. 



t. r. h. 



Day Av. 80° F.± 5°. Day Av. 75 per cent. ± 5 per cent. 



Night Av. 75° F.zb 8°. Night Av. 75 per cent. =h 5 per cent. 



In the Fj generation the larvae were all alike, as was to be 

 expected since the larval stages of the parental stocks are simi- 

 lar. These larvae gave rise to F^ hybrid adults distributed 

 in two sharply marked groups. One of these groups was 

 indistinguishable from the female parent stock, and the other 

 was an intermediate between the male and female parental stocks, 

 in which the essential contrasting character between the adults 

 was in the elytral stripes and these were distinctly midway 

 between the two parent types, (a blend). The numbers were 49 

 of the signaticollis type (sig. type), to 53 of the mid type (mid 

 type) — practically a i : i ratio. 



Several pairs of each of these types were mated for the Fg 

 generation. The matings of the signaticollis type gave in the F2 

 generation pure signaticollis, and further breeding for five con- 

 secutive generations gave only signaticollis types. The progeny 

 of the mid type, however, split in the F2 generation into three 

 classes, with perfect Mendelian ratios, one like the female sig- 

 naticollis type, one like the male diversa type, and the mid type. 

 For example, pair A, gave: • 



1 These experiment numbers are those of the original records, which are now 

 attached to the specimens preserved as a record of this work. 



