TnE SLUG. 185 



soon acquires a covering of greenish black slime, and is said by Harris 

 to live as a worm twenty-six days, shedding its skin during that period 



Fig. 61. Fig. 62. 





Fig. 61. The Egg magnified, with the Embryo Slug seen through the shelL 

 Fig. 62. The Egg empty after the Slug has escaped — magnified. 



five times. Fig. 63 gives its appearance after it has shed its skin for the 

 last time, with the forsaken skin lying near it. It is now much changed 

 in color, being a brown-yellow, and somewhat diminished in size. In 

 a few hours it falls to the ground, and immediately seeks to burrow into 

 the soil. Descending to the depth of several inches, it forms a cocoon 

 with a shiny brown interior surface, and a rough exterior, with 

 grains of earth adhering. Fig. 64 shows a broken cocoon with the 



Fig. 63. Fig. 64. Fig. 65. 



Fig. 63. (a) The Slug, after shedding its skin the last time. (&) The skin left upon 

 the leaf. 



Fig. &4. (c.) The Cocoon from which the insect has been prematurely removed. 

 {d) The Slug after having commenced its change to the fly state. 



Fig. 65. The Ichneumon Fly magnified; supposed to be of the species Encyrtus, 

 taken from the egg of the slug. 



insect, now much further diminished in size, taken out. This is the 

 Ptipa or dormant state. It remains in the earth after its first appear- 

 ance sixteen days, when it comes forth as the perfect insect. Fig. 60. 

 The second brood remain in their subterranean retreat until the suc- 

 ceeding spring. 



" We will now consider the means for preventing or palliating the 

 injury resulting from the attacks of the pear-slug. I would first remark, 

 that the slug is found in much greater abundance on weakly growing 

 trees than on those of strong and rapid growth. This fact points to 



