274 OHIO EXPERIMENT STATION: BULLETIN 332 



masses and the whole is covered with the buff scales from the under- 

 side of the insect's body. The mass so covered is aptly described 

 by Doctor Felt as closely resembling a small sponge. 



The catei-pillar when first hatched is about one-tenth of an inch 

 in length and heavily covered with brownish-yellow hair. The full- 

 grown caterpillar is from 2 to 2i/^ inches in length, grayish-brown 

 in color with four rows of prominent blue and red tubercles extend- 

 ing lengthwise of the body. Further adorning the body are num- 

 erous well-defined tussocks of black and light yellow hairs. 



The pupa is rich brown in color, and varies from three-fourths 

 of an inch to li/^ inches in length. It is sparsely decorated with 

 tawny hairs and is usually suspended by a few silken threads to 

 which it is secured by the hooks at the tip of the abdomen. 



Life history and habits. — The winter is passed in the egg stage 

 in the masses previously described. The greater part of the larvae 

 hatch during late April and early May, and the main part of the 

 caterpillar brood matures by early July. The caterpillars feed 

 mainly during the nighttime, remaining clustered on the tree or 

 secreted in hollows and the like, during the day. The early part of 

 July is spent in the pupal stage,- the moths appearing about mid- 

 July to deposit their quota of over-wintering eggs. The males fly 

 readily, but the females, while having perfect wings, are unable 

 to fly. 



How the insect spreads. — Burgess (36) in his exhaustive dis- 

 cussion of the spread of the gipsy moth calls attention to several 

 methods by which the pest is disseminated, the more important of 

 which are as follows: 



A close examination of the very young larvae of the gipsy moth 

 reveals the fact that the insect is clothed with two types of hairs; 

 the normal slender type and others which have an enlarged bulb 

 near the base. Still further seeking shows these bulbs to be noth- 

 ing other than miniature balloons. Because of their great number, 

 the body of the caterpillar is rendered quite buoyant and easily 

 carried by the wind ; hence the floating young caterpillars constitute 

 one of the chief means by which the species is spread. Under the 

 most favorable conditions the catei-pillars can float long distances, 

 it having been proved that they can travel in this manner as far 

 as 20 miles. 



Another important means of dispersal is the transporting of 

 the insect chiefly in the egg or larvae stage. Since the eggs are 

 laid upon a wide range of objects, such as board piles, packing cases, 

 fencing, stone and other building materials, which are likely to be 

 shipped during the winter from point to point, abundant appoi'tunity 



