INSECTS. 123 



the ground will be caught and killed. If greater pains were to be 

 taken to destroy the insects in the caterpillar state, their numbers 

 would soon greatly diminish. 



Even after they have left the trees, have gone into the ground, 

 and have changed their forms, they are not wholly beyond the 

 reach of means for destroying them. In orchards, in the autumn, 

 root up and kill great numbers of the chrysalids of' the canker- 

 worms. Some persons have recommended digging or plowing 

 under the trees, in the autumn, with the hope of crushing some of 

 the chrysalids by so doing, and of exposing others to perish with 

 the cold of the following winter. If hogs are then allowed to go 

 among the trees, and a few grains of corn are scattered on the 

 loosened soil, these animals will eat many of the chrysalids as well 

 as the corn, and will crush others with their feet. 



Apple, elm, and lime-trees, are sometimes injured a good deal 

 by another kind of span-worm, larger than the canker-worm, and 

 very different from it in appearance. It is of a bright yellow color, 

 with ten crinkled black lines along the top of the back ; the head 

 is rust-colored ; and the belly is paler than the rest of the body. 

 When fully grown, it measures about one inch and a quarter in 

 length. It often rests with the middle of the body curved upwa xls 

 a little, and sometimes even without the support of its fore-legs. 

 The leaves of the lime seem to be its natural and favorite food, for 

 it may be found on this tree every year ; but is seen in considerable 

 abundance, with common canker-worms, on other trees. It i?, 

 hatched rather later, and does not leave the trees quite so soon as 

 the latter. A-bout or soon after the middle of June it spins down 

 from the trees, goes into the ground, and changes to a chrysalis in 

 a little cell five or six inches below the surface ; and from this it 

 comes out in the moth state towards the end of October or during 

 the month of November. More rarely its last transformation is re- 

 tarded till the spring. The females are wingless and grub-like, with 

 slender thread-shaped antennae. As soon as they leave the ground 

 they creep up the trees, and lay their eggs jn little clusters, here 

 and there on the branches. * 



As these span-worms appear at the same time as canker-worms, 

 resemble them in their habits, and often live on the same trees, they 

 can be kept in check by such means as are found useful when em- 

 ployed against canker-worms. 



THE HOP CATERPILLAR. The hop-vine is often infested by great 

 numbers of caterpillars called Herminians, of the grc up Pyralides, 



