296 WILLIAM LAWRENCE TOWER. 



conclusions drawn from the first two experiments and showing 

 beyond doubt that the variabiHty of behavior in the alter- 

 native inheritance of the eltyral stripes in these two species of 

 beetles was due to conditions surrounding and incident upon the 

 germinal materials in their most sensitive stages, before, during 

 and immediately following fertilization. The behavior common 

 to this type of experiment is shown in Plate III. 



With this cross of an L. signaticollis 9 X d" L. diversa, the 

 determination of dominance and the ensuing type of behavior is 

 clearly a function of the conditions incident upon the combining 

 germ plasms. In the repitition of Exp. No. H 409/411, the 

 experiment was varied so that in some cases it was the first 

 laid eggs that gave the behavior of Exp. No. H 409, and in others, 

 it was the last laid eggs, or those of the middle of the reproductive 

 period — showing that the results are not "age results," nor due 

 to segregations, nor orthogenesis giving one kind of germ at the 

 start, another at the middle, and others at the close of the repro- 

 ductive period. 



Crosses Between L. signaticollis and L. undecimlineata. 

 More interesting and complicated results were obtained in 

 crosses between L. signaticollis and L. undecimlineata, where 

 there are contrasting characters between both larvae and adults, 

 differences in the specific pattern as a whole, in specific spots 

 and in the general body color. Reference to Figs, i and 2 will 

 show essentially what these differences are, as far as pattern and 

 spots are concerned. In body color of the larvae the difference 

 is between a white in L. undecimlineata and a bright chrome 

 yellow in L. signaticollis. 



L. undecimlineata 9 X d^ L. signaticollis. 

 Exp. No. H 700 A. 

 A virgin female of L. undecimlineata, from Ex. No. 722, g. Ill 

 (AA) was crossed with a male L. signaticollis from Ex. No. 419, 

 g. XIII (CAAC) under the following conditions: 



Food : Normal — uniform. 

 T. R. H. 



Day Av. ± 95° F. 3.5°. Day Av. 84 per cent. ± 8 per cent. 



Night Av. ± 89° F. 4.8°. Night Av. 100 per cent. 



