Geometridae 



Fig. ig^.—Pti/eacrita ver- 

 nata. a, mature larva; ^, egg, 

 magnified, natural size shown in 

 mass at side ; c, enlarged seg- 

 ment of larva, side view ; d, 

 do., viewed dorsally. (After 

 Riley.) 



Canker-worm, because the great majority of the moths issue 

 from the ground in the spring. It has been a great pest in 

 orchards, and formerly in our East- 

 ern cities was a nuisance, not only 

 because of the injury which it inflicted 

 upon the foliage of shade-trees, but 

 because of the annoying manner in 

 which the larvae, pendent from the 

 branches by long threads of silk, were 

 blown about over things and persons 

 beneath them. It was to effect their de- 

 struction that the English sparrow was 

 originally imported into this country. 

 The ravages of the insects upon the 

 foliage of trees in parks and gardens have measurably decreased 

 since this step was taken, but in the open country, especially in 



the Valley of the Mississippi, 

 the insects are still numerous 

 enough to do much harm 

 to orchards. The females 

 being apterous, the best 

 method of preventing the 

 multiplication of the insects 

 upon trees is to prevent 

 them from climbing up 

 upon the foliage and ovipositing. A simple device, which has 

 proved very effective, is to tie a piece of rope about the trunk 

 of the tree which it is intended to protect, and to insert between 

 the rope and the bark strips of tin, which, having been put into 

 place, should be bent downwardly and outwardly, so as to form 

 a collar with a downward flare. The insects have been found 

 not to be inclined to pass such a barrier, and they will congregate 

 just below it, and may there be captured and destroyed. Birds 

 are the chief enemies of the canker-worm, and every wise or- 

 chardist will see to it that all species of insectivorous birds are 

 not molested in his neighborhood, but are encouraged to find in 

 his trees a hospitable welcome. The small amount of fruit 

 which the birds take as toll is amply compensated for by the 

 work which they perform in keeping down insect pests, such as 



Fig. 196. — Palcacrita vernata. a, male; /', 

 female ; c, joint of antenna ; d, joint of ab- 

 domen ; e, ovipositor. (After Riley.) 



