GROWTH AND TRANSFORMATIONS OF INSECTS 59 



when the sky becomes clouded 

 and rain threatens. While 

 young they feed together, each 

 little caterpillar spinning a fine 

 strand of silk wherever it goes, 

 which forms a sort of trail for 

 the others. They become full 

 grown in six or seven weeks, 

 during which time they have 

 molted some four or, excep- 

 tionally, five times, at intervals 

 of eight or nine days, though 

 the length of time between 

 molts varies widely according 

 to the food supply and weather 

 conditions. After the fourth 

 molt the fifth stage occupies 

 about two weeks before the 

 FIG. 75. Tent caterpillars about half grown caterpillar transforms to the 

 on web pupa. When full grown they 



(Photograph by Weed) , 



become extremely restless, wan- 

 der away from the nest, and are frequently encountered on walks 

 and roadsides, 

 and feed on al- 

 most any plant 

 found. They 

 are now about 

 two inches in 

 length, deep 

 black in color, 

 thinly covered 



* 



with yellowish 

 hairs, with a 

 white stripe 

 down the mid- 

 dle of the back. 



At the middle FIG. 76. Full-grown tent caterpillars on web. (Reduced) 

 Of the side of (Photograph by Weed) 



