DEPARTMENT OF EXPERIMENTAL EVOLUTION. 113 



When lamarckiana enters into the hybrid combination the situa- 

 tion becomes extremely complex. At many points the same principle 

 which works out with precision among the pure cruciata crosses can 

 be detected with greater or less clearness, but in most cases it is 

 obscured or completely hidden or destroyed by the more independent 

 movement of characteristics of lamarckiana, including the broad 

 petals, long style, redness of the bud-cones, and various features of 

 foliage and habit of branching, all of which may be recombined in 

 various waj's with the cluster of egg-borne or sperm-borne characters 

 of any biotype of cruciata with which lamarckiana may be crossed. 

 These independent characters of lamarckiana do not readily take a 

 iNIendelian interpretation, however, the same character being in one 

 combination dominant, in the other recessive, and almost never 

 approximating an expected ratio, except perhaps 1 : 1 in several cases. 

 Broad and narrow petals not infrequently occur on the different 

 branches of the same plant. 



Heredity in Butterflies, by John H. Gerould. 



Professor John H. Gerould has been cooperating, as non-resident 

 collaborator, in researches on heredity in butterflies. He makes 

 the following report: 



My principal work with butterflies this season has been with Colias 

 eurytheme, in which I have studied the inheritance of albinism; I have 

 material for the study of other color varieties, as keewaydin and ariadne; 

 and I have again crossed this species with C. philodice. I have mated the 

 species-hybrids together and with individuals of the original species, and 

 have secured a few layings of fertile eggs from these matings. I expect this 

 fall to raise butterflies from these eggs, or to bring them into the pupal stage 

 before I put the stock entirely into winter quarters. The albino female of 

 C. eurytheme, as in C. philodice, is a color-hybrid, a Mendelian heterozygote 

 for color. Thus, from two white females of eurytheme received from Arizona 

 early in June 1913, 1 raised family a, containing 29 white females, 24 orange- 

 yellow females, and 57 males -|- 1 gynandromorphic male; b, containing 

 27 white females, 20 orange-yellow females, and 49 males. 



One-half of the sons of a white female are presumably heterozygous 

 for color, though yellow; so I have attempted to determine the proportions 

 derived by mating white (heterozygous) females with heterozygous yellow 

 males, whether 3 white females to 1 orange female, or 2 white females to 

 1 yellow female, as my experiments on C. 7)/n7o(iice seemed to indicate; but 

 my broods of this generation that have just been emerging do not settle 

 the question. The families from white females mated to their own brothers 

 (or other sons of white females) in which an excess of white female offspring 

 appeared were small. In one such, e (from a^'^, white female X a" male), 

 9 white females and no orange females (-1-15 males) have thus far appeared. 

 Possibly a-^ male was a heterozygote for white, y (w), though, of course, 

 yellow. In family m (ex ¥^ white female X ¥^ male, i. e., son and daughter 

 of a wild white female from Arizona) there are 38 males, 16 white females, 1 1 

 orange-yellow females; ¥^ male, the father, was presumably pure orange- 

 yellow, not carrying the white latent. 



