THE INSECT WORLD. 



321 



SO as to warm up rapidly, but there is danger in holding too long, 

 because if the plants start under water, as they sometimes do, the 

 crop is ruined. Occasionally, however, it pays to lose a crop 

 in whole or in i)art, to free the bogs completely of this insect, as 

 they will then remain practically safe for several years in succes- 

 sion. Wliere water is abundant and the bogs can be readily 

 reflowed, the practice of the present day is to draw the water 

 early to induce an early hatching of the insects, and as soon as 

 the larvce generally appear, reflow, leaving on the water at 

 least twenty-four hours. This will not hurt the plants at that 

 period of their growth, and will kill every caterjjillar upon the 

 bog. The effect depends largely upon the care with which it has 

 been done and upon the judgment exercised as to the proper 

 time. It should be de- 

 layed until the great ma- Fig. 370. 

 jority of the eggs have 

 hatched, l)ut should not 

 be delayed so as to run the 

 risk of injuring the plants. 



In the genus Caccecia 

 we have several injurious 

 species, and none more an- 

 noying than C. rosaccana. 

 This attacks a great va- 

 riety of plants, but it is 



most troublesome on roses, spinning and folding leaves and buds 

 and so destroying the flowers. These larvae are not easily dealt 

 with, but spraying the plants with pyrctln-um or kerosene emul- 

 sion as soon as the first signs of injury are observed will generally 

 serve to keep them down. On a small scale they may be con- 

 trolled by compressing the s])un-u]) leaves and killing the cater- 

 pillar in its home. 



Some of the species live in communities, making a nest or 

 web, and such is the Caccecia fervidava, the caterpillar of which 

 lives on oak, and spins up the shoots of young trees or the tips 

 of the branches of older ones. In some cases the nests become 

 from three to six inches in diameter, and when the caterpillars 

 have reached their full growth they pupate within it, wriggling 

 out through the silken. covering when ready to emerge as moths, 



2; • 



Rose leaf-roller, C'ar/m'a rnsacrana. — Larva, 

 pupa, and aclull. 



