1943] 
Bionomics of Ectopsocus pumilis 
59 
Moulting. — Often the nymphs ate their exuviae, thus mak- 
ing it difficult to determine moults in cases where measuring 
was impossible. The majority of the exuviae were in a vertical 
position with the head down, but some were horizontal. Moult- 
ing seemed to be the same as that described for C. manteri (6). 
The epidermis split along the top of the thorax and head. The 
nymph arched up, with the antennae held down along the sides 
of the body. The head was finally freed and gradually the 
nymph rose until it was actually resting on the end of its abdo- 
men, although the tarsi of the exuviae were in contact with the 
substratum. When almost vertical the antennae were released, 
then the legs. All this time air bubbles were being swallowed 
and the abdomen stretched out. After moving the legs it bent 
over, freeing the tip of the abdomen, and stood beside the exu- 
viae. After a short time the abdomen contracted to its normal 
length. One adult was observed from the time it first freed its 
legs from the exuviae until its wings were completely unfolded. 
Five minutes after freeing the legs it walked from the exuviae. 
The wings were beginning to unfold; so it turned around to a 
vertical position with the head up. In twelve minutes the wings 
were completely straightened and were the same light color 
throughout. After the third instar one can determine when 
moulting will occur because the thick wing pads stick out from 
the body as in Figure 6. 
Habits. — Under laboratory conditions the nymphs and 
adults eat fungi, epidermis and mesophyll of the corn sheaths, 
pollen, embryo and starch of broken corn kernels, exuviae, and 
dead of their own kind. This species seemed to get along very 
well on the embryo and starch of the corn kernels. In some 
cases when they finished there was nothing left but the hard 
yellow seed coat of the kernel. Silk is deposited by the nymphs 
and adults. Although the quantity produced by E. pumilis is 
considered rather conspicuous it is a small amount in compari- 
son to that deposited by E. calif ornicus. E. pumilis , like C. 
manteri , gave a sudden start when the cotton plugs in the rear- 
ing cages were moistened, and they usually pushed their mandi- 
bles into the cotton and took water from the plugs. There 
seemed to be a tendency for both the nymphs and adults to 
walk upward, if confronted with a vertical surface. This nega- 
tive geotropism made this species easy to handle. If a glass 
tube were placed over an escaped nymph or adult it immediately 
