Studies on the Variability and Heritability of Pigmentation in Oenothera. 343 
of the mature bud very early, when the buds are of small size. It 
is at this time very commonly of a darker shade (dark brownish red), 
becoming lighter as the bud develops. Buds only one cm. in length 
frequently show the full color pattern. In this connection I may call 
attention to some observations upon the effects of the attacks of a 
certain insect on the buds of Oenothera. When the buds are very 
young, they are stung by this insect (name undetermined) which 
deposits probably a single egg in the bud. Later a small larva, 
marked with pink transverse bands, appears and feeds upon the 
anthers, afterwards eating its way out of the bud to pupate in the 
ground. Buds thus attacked undergo several remarkable changes. 
The hypanthium fails to develop, or remains very short with much- 
thickened walls. As the bud matures, the base of the cone becomes 
nearly twice its normal diameter, and as the cone is also shorter 
than normal, its slope is very abrupt. In buds of O. Lamarckiana 
(and the same is true of some, as least, of the mutants) there is also 
invariably the development of an exceptional amount of red on the 
sepals (rather more than in typical O. rudrinervis 5). On the other 
hand, the buds of O. diennis (an American race from New York) when 
similarly attacked, undergo exactly the same morphological changes 
but in no case did I find any red whatever developed on the sepals, 
although a large number of such parasitized buds were examined from 
a culture at Wood’s Hole in 1908. This difference is sufficiently 
striking and may be of significance. MIRANDE (1907) and others have 
similarly found a development of anthocyan as the result of insect 
attacks, probably due to an accumulation of sugars. 
DE VRIES, and also MAC DOUGAL, SHULL and others have made 
observations on the buds of O. Lamarckiana as compared with those 
of O. rubrinervis and other forms. The cone of the O. Lamarckiana 
bud is frequently somewhat squarer and slenderer. It is also usually 
more yellowish than that of O. rudrinervis, and sometimes there are 
extremely narrow fine longitudinal reddish lines along the marginal 
area of the sepals. These appear to be quite distinct in character 
from the color pattern of O. rubrinervis. In the latter they have never 
been seen to occur, not even when the characteristic red bands are 
wholly absent. 
No change in the mode of an individual during the season has 
been observed, but O. ruörinervis plants which come into bloom late 
in the season have always been observed to show a somewhat reduced 
color pattern on their buds. Whether this is a direct effect of altered 
