LIFE BISTORY OF THE GIPSY MOTH. 13 



HIE LARVJ; 



(PL I, fig. 6.) 



The newly hatched caterpillars feed upon the small leaves, making 

 "pin holes" in them. As a rule the caterpillars molt five times, but 

 quite a number of cases are on record where an additional molt took 

 place before they entered the pupal stage. The newly hatched cater- 

 pillars are about one-eighth of an inch in length and covered with long, 

 slender hairs. During warm weather they feed upon the leaves, but 

 when the temperature is low, or during rainy or unsettled weather, 

 such as is common in early spring, they congregate in masses in the 

 crevices of the bark or on the egg clusters from which they hatched. 

 As the weather becomes warmer in the early summer, they grow rap- 

 idly and devour the entire leaves except the woody veins. Until they 

 are about half grown, the caterpillars are able to suspend themselves 

 from the twigs or branches of the trees by means of silken threads 

 spun from their bodies, and in this way they often drop upon animals, 

 carriages, or other moving objects, and may be conveyed to localities 

 where none of the species exists. After the caterpillars have molted 

 the fourth time, which usually occurs about the middle of June, a con- 

 siderable change in coloration appears. On the dorsum of each of the 

 first five segments behind the head is a pair of prominent blue tuber- 

 cles, while on the following six segments the tubercles are of a dark- 

 red color. The arrangement and coloration of these tubercles Is 

 characteristic of the species. The feeding habits change somewhat 

 with the progress in growth of the caterpillars, for after becoming half 

 grown the caterpillars seem to prefer shelter from the sun and feed 

 for the most part at night or during cloudy weather. During the 

 warm part of the day they remain concealed in crevices in the bark, 

 crawl to the ground, or seek any convenient shelter from the sun. 

 This habit serves as a protection against their natural enemies, and 

 although in moderately infested sections it is usually possible to find 

 caterpillars feeding at midday during sunny weather, still the ma- 

 jority are either in hiding or are feeding in such situations as to be 

 largely protected from direct sunlight. The period spent in the cater- 

 pillar stage extends, on the average, from early in May to July 5, or is 

 approximately seven weeks. Egg clusters deposited in cool situations 

 do not hatch as readily as those more favorably Located; hence 

 the entire length of the feeding period varies considerably. Larvae 

 have been found as early as the 1st of April and as late as September 

 6. In certain areas along the seacoast and on islands which are sur- 

 rounded by tidewater, the hatching of the eggs is retarded, and pupa- 

 tion takes place much later than where conditions are normal The 

 full-grown caterpillars measure about L* inches in length, although 

 there is considerable variation in this respect, due Largely to the 



