No. 4.] FRUIT TREES AND INSECT FOES. 127 



female moth ; c, d, structural details. 



The fall canker worm (AlsophUa pometaria Harr.) appears 

 late in the fall, coming out of the ground; and the wingless 

 females crawl up the trees to the smaller limbs, where the eggs 

 are laid in clusters. In the spring these eggs hatch, producing 

 tiny "inchworms," which 

 feed on the leaves till 

 full grown, this condition 

 being reached in June. 

 They then crawl down 

 the tree or spin down 

 a thread to the ground, 

 where a few inches below the surface they pupate. Here they 

 remain till the approach of cold weather, when the insects, 

 now in the moth stage, leave the ground and pass to the trees 

 to lay the eggs for the generation of the following year. 



In the case of the spring canker worm (Paleacrita vernata 

 Peck.) the moths do not appear in 

 the fall, but during the first warm 

 days in March and April; and, like 

 the others, the females crawl up the 

 trees to lay their eggs on the twigs, 

 and it is possible that a cluster of 

 freshly laid eggs of the spring canker 

 worm may be placed close beside a 

 cluster of eggs of the fall canker 

 worm which have been there all winter. The eggs of both 

 kinds will hatch at about the same time, however, and their 

 feeding will also be com- 

 plete at about the same 

 period ; but, while the 

 spring canker worm will 

 then remain in the 

 ground till the following 

 spring, the fall canker 

 worm will spend but a few months there, the winter being 

 passed in the egg on the twigs. 



From the above it is evident that any treatment which will 

 prevent the wingless female from ascending the tree to lay her 

 eggs will be successful, and for this purpose sticky bands and 



Fig. 12. — Spring canker worm: 

 a, full-grown caterpillar; b, 

 enlarged egg, and part of a 

 mass, natural size ; c, d, struc- 

 tural details. 



Spring canker worm 



b, female moth ; c, d, e, structural detail- 



moth; 



