36 



men, which are used to cut fine slits into the leaf-substance, into which 

 The eggs are pushed. Here they increase to almost twice their original 

 size by absorbing the sap of the plant through their very thin shells, 

 thus preventing their dislodgmcnt until hatching time. The under side 

 of the leaf is invariably utilized for oviposition. The appearance of 

 oval bladder-like projections upon the upper surface of the leaf is pro- 

 duced by the eggs, as already mentioned. They show still more plainly 

 upon the lower surface, where it is seen that the eggs are only partly 

 imbedded in the little pockets produced by the saws of the female. If 

 the leaf substance at the time of cutting these slits is still soft and yield- 

 ing the whole egg is snugly imbedded; otherwise one-third and even 

 one-half of the egg projects outside. The egg itself is quite large in 

 proportion to the mother insect, measuring fully 0.3""". in length. It 

 has a long oval shape and is one-third as wide as long. These trans- 

 lucent, greenish eggs are quite numerous, as each female lays on an 

 average about eighty eggs at a time, and since — in time of scarcity of 

 young foliage — several females sometimes select the same leaf, as 

 many as two hundred eggs have been counted upon a single leaf. The 

 eggs deposited later in these leaves by a second female are usually de- 

 stroyed, because the offspring of the first hatch of eggs commence feed- 

 ing as soon as born and devour the leaf, together with the inclosed 

 eggs. In the course of four to eight days the young slugs are hatched. 

 Tiie time of incubation varies and is controlled by the prevailing tem- 

 perature. 



The Larva, Pupa, and Cocoon. — When the young larvte leave their egg- 

 shells, they are at first white, with a small blackish eye-spot on each 

 side of the head, which is already visible through the shell of the un- 

 hatched egg. This white color soon disappears, and later the slugs 

 are shiny black, transversely wrinkled, and ornamented with ten large 

 and two smaller yellow spots on each side of the body along the stigmatal 

 region. A slimy matter oozes out of their skin and covers them en- 

 tirely. The large yellow spots are very prominent only after the last 

 molt; but they are already vaguely indicated in the younger specimens, 

 which are moreover frequently marked by a narrow, yellow longitudinal 

 dorsal line. Often there are but ten spots, the ones upon the first tho- 

 racic and last abdominal segment being either quite small or lacking. 

 The head is polished black, free, perpendicular, and as large as the 

 first segment. Besides the three pairs of long, black, jointed feet, of 

 which the first pair is shortest and the third longest, the slugs possess 

 six pairs of light blue prolegs and a seventh pair of very imperfect anal 

 ones. 



The larvre undergo four molts, and attain maturity in from ten 

 days to three weeks. When fall grown, they measure fully 20"'"^ in 

 lengtli, and ceasing to feed, enter the ground where they form shiny, 

 glue like cocoons, of a dark bronze color. These cocoons are double, 

 and consist of a rough outside layer inclosing a smooth and tough 



