1926 ] 
Color and Sex in the Indian Walking Stick 
151 
COLOR AND SEX IN THE INDIAN WALKING STICK, 
DIXIPPUS MOROSUS 
By A. J. Mangelsdorf, 
Harvard University, Bussey Institution. 
In cultures of the Indian walking-stick, Dixippus morosus, 
reared in the insectary at the Bussey Institution, it was observed 
that in each generation there was a wide range of coloration 
varying from a uniform green in some individuals to a brownish 
black in others. Since this insect usually reproduces partheno- 
genetically the question as to the behavior in inheritance of the 
several color types appeared to be one of considerable interest. 
Dobkiewicz (1912) had already shown that the color of 
these insects is influenced by their surroundings. He reared 
them in cages lined with colored paper, and found that those in 
green and yellow cages remained light green throughout their 
lives, while those in red and black cages had become quite black 
by the time they had reached sexual maturity. However, the 
occurrence in our cultures under what appeared to be a uniform 
environment of green and dark brown individuals, in addition to 
a number which were intermediate between the two extremes, 
suggested that there might be inherent individual differences in 
reactivity to a background of a given color. 
To obtain further information on this question two females, 
one a light green and the other a dark brown, were isolated and 
their eggs saved. The eggs are dropped at the rate of two or 
three a day, and egg-laying may extend over a period of three to 
five months. Over one hundred eggs were obtained from each 
female. They were placed in wide-mouthed bottles stoppered 
with a cotton plug, and were stored in a damp situation in the 
insectary. In about five months after the first eggs were laid, 
hatching began. 
Four cages were constructed, — two were lined with light 
yellowish-green cheesecloth and two with the same material of a 
very dark red color. After a number of eggs from both the green 
