8 CIRCULAR 4 6 4, IT. S. DEPARTMENT OF AGRICULTURE 



absence of water becomes less of a problem as the larvae increase 

 in size, probably because of the decrease in the ratio between evapo- 

 rative surface and body volume. 



First-instar larvae move very slowly. They are active only when 

 the temperature is above 60° F. and are more active when the temper- 

 ature is 70° or higher. 



Gypsy moth larvae that are to become male moths molt five times, 

 and those that are to be females molt six times. The full-grown 

 larva is from 1% to 2 l / 2 inches long. The head has yellow markings; 

 the body is dusky or sooty colored, hairy, and on the dorsum is a 

 double row of Rye pairs of blue spots followed by a double row of six 

 pairs of red spots. As the larvae grow, the quantity of foliage eaten 

 per day increases tremendously. Approximately 75 percent of all 

 the foliage eaten by larvae having- five instars is eaten in the fifth 

 or last instar, and approximately 65 percent of the foliage eaten by 

 larvae living through six instars is consumed in the last instar. Con- 

 trol measures against larvae should therefore be applied as soon as 

 possible after the eggs hatch, to protect the foliage from the later 

 instars. 



THE PUPAE 



When full grown, the larvae shed their skins and transform to 

 chestnut-brown pupae bearing tufts of yellow hairs. After about 10 

 days in this stage the adult moths emerge. 



THE ADULTS 



The male gypsy moth is dark brown with black wing markings, 

 and is a strong flier. The males usually emerge earlier than the 

 females, and fly near the ground, in a characteristic zigzag manner, 

 in search of female moths. 



The female moth is nearly white, with black wing markings, and 

 is much larger than the male. Because of the weight of their bodies, 

 the females are incapable of flight, and are usually found beside their 

 empty pupal cases. Here they deposit their eggs, and once this 

 function has been performed they die. Oviposition begins within a 

 day or two after the female emerges from the pupa. The moths do 

 not feed. 



INJURY CAUSED BY THE GYPSY MOTH 



It is impossible to state with precision the loss to New England 

 forests due to the ravages of the gypsy moth. The best information 

 compiled from data extending over a long period of years indicates 

 losses of many millions of dollars in tree growth. These losses have 

 been due not only to the direct or indirect killing of the trees but 

 also to the retardation of growth through defoliation. Although far 

 less spectacular than the immediate killing of trees, the second type 

 of loss is more to be feared, for tens of thousands of trees are so 

 affected for every one killed. Most conifers, notably hemlock and 

 white pine, are killed by a single complete defoliation. Most rapid- 

 growing deciduous trees put out a new crop of foliage the same season 

 in which stripping occurs; they are therefore without foliage but a 



