The Palmer-AVorm. 107 



There is thus one stage — tlie egg — in tlie palmer- worm's life 

 that we know nothing definite al)ont. ]>iit our ohservations have 

 filled the great gap from July till the next spring, and it now 

 remains for someone to discover the ego;, which we believe is laid 

 and hatched in May, and thus complete the life-story of the insect. 



Natural Enemies. 



That the palmer-worm has appeared in injurious numbers only 

 three times in over a century is largely due, we believe, to the 

 efficient work of its enemies in Nature. Among these checks to its 

 increase, certain climatic conditions doubtless rank fii-st. Apparently 

 excessively dry and hot weather in April and May is much more 

 favorable for its development, and both Fitch and Harris agree that 

 palmer-worms of all sizes suddenly disappeared from the trees in 

 1853 with showers of rain in June. The rain probably jars or 

 knocks the caterpillars from the foliage onto the ground, and it 

 may then kill them, or more likely they do not find their way back 

 to the foliage. Tlius the moist conditions which usually prevail in 

 the spring and early summer apparently serve as Nature's most 

 effective check to the development of this insect iu injurious 

 numbers. 



The palmer-worm also falls a prey to enemies among its own kind. 

 Fitch has graphically told the story thus : " Numbers of these worms 

 are every year destroyed by a small footless grub or maggot, which 

 lives in the palmer-worm until it -has attained its grow^th, when it 

 perforates a hole through the side of the worm, and crawding out 

 spins a small, white, oval cocoon for itself, commonly attaching this 

 cocoon very slightly to the surface of the leaf. The worm from 

 which this parasite has crawled remains upon the leaf beside it, its 

 feet seemingly paralyzed, so that it is unable to move from the spot. 

 It turns its head at times from one side to the other, but eats no 

 more and soon perishes." Harris states that more than half of the 

 caterpillars he tried to rear in 1853 \vere killed by this little para- 

 site. Several of the caterpillars in our cages also succumbed in a 

 similar manner in June last ; it was doubtless the Avork of the same 

 parasite that killed so many of the caterpillars in 1853. 



From the little cocoon spun beside their dying host, we reared a 



