Dichromatism m Lina Lappojiica. 121 



sex were discarded. By this means individuals were limited to 

 mates of a definite color without forced mating. A pair once 

 mated, however, were mated for lite, as they were then removed 

 to a I X 4 inch shell vial and numbered. Here they lived and 

 reproduced for the rest of their lives. 



Each mass of eggs oviposited was removed to a 12 ounce breed- 

 ing jar for further development, and given its parental number. 

 In this way 288 individuals were mated, representing 144 crosses. 

 Of these, ten pairs produced no eggs, although copulation took 

 place several times, nineteen pairs produced eggs that failed to 

 develop, nine pairs produced eggs that went through pre-embry- 

 onic development, but failed to hatch, and 106 pairs produced 

 eggs that hatched in from three to six days, the offspring reaching 

 maturity in about twenty-five days from the date of hatching. 

 The 106 pairs represented the following matings: 



57 pairs of S d^ X S 9 



19 pairs of B d" X B 9 



14 pairs of B d" X S 9 



16 pairs of S d" X B 9 



Table I, compiled from the records of individual broods, gives 

 a summary of the data obtained. 



We find, therefore, that in a lot of 57 d" S's mated with a lot of 

 57 9 S's without respect to ancestry, that over one-half reproduce 

 their kind, while the others produce mixed broods (32 : 25). 

 The mixed broods are made up of individuals representing the 

 extremes of color only — no blends — in the proportion 890 S : 280 

 B, or 3.2 S : I B. 



Also in a lot of 19 d^ B's and 19 9 B's, the parents chosen at ran- 

 dom without respect to ancestry, two sorts of broods are produced, 

 namely, broods true to parent color and mixed broods, in the pro- 

 portion 14 pure : 5 mixed. The mixed broods are made up of 

 individuals representing the extremes of color only, in the pro- 

 portion I S : 1.7 B. 



Therefore, from parents chosen at random, but similarly mated, 

 two sorts of broods are obtained, broods true to parental type, or 

 pure broods, and mixed broods, the preponderance of individuals 

 being in each case on the side of the color type of the immediate 

 parents. Records of individual broods show that this condition 



