20 THE SUGAR-BEET WIKEWORM. 



seems to have little effect on the hatching of the eggs, as some which 

 were kept partially submerged part of the time hatched in good 

 shape. 



As hatching time approached, large, UTegular, hyaline areas ap- 

 ])eared in the eggs in various places. At first nothing could be seen 

 of the embryo, but about a week before hatching its outlines could 

 be made out with difficulty. The embryo became little plainer, 

 even at the time of hatching. 



LENGTH OF EGG STAGE. 



The length of the egg stage varied under laboratory conditions 

 from 23 to 33 days, most of the eggs hatching in from 27 to 30 days, 

 so that the length of the egg stage may be roughly considered as a 

 month. It seems probable that the period might be shortened mal(>- 

 rially under favorable conditions, out of doors, and eggs laid in the 

 warm damp soil might i)ossibly hatch in from 15 to 25 days. 



The Larva. 



emergence from the egg. 



The larva? (PL II, fig. h) emergen from the eggs by eatmg a small 

 hole in the shell and crawling out. In all the cases noted the hole 

 was very little larger than the body of the wireworm, so that it is a 

 matter of a few moments for the young wireworm to leave the shell 

 entirely. In the case of several which were timed, between two and 

 seven minutes elapsed from the appearance of their heads through 

 the shell until they were entirely free. During the earlier part of the 

 hatching season no eggshells could be found, and it was thought 

 ])robable that the larva on emergmg used the shell for food. Such 

 did not prove to be the case, however, as later, when more eggs were 

 hatching, it was observed that the larva on hatchmg leaves the old 

 shell almost at once. In a few cases the larvae crawled around the 

 shells for a short tune but did not attempt to eat them and always 

 left them intact. Where the eggs are hatching in the soil, the young 

 larva remams for a short time in the cavity occupied by the egg. 

 That the eggshells are quite tough was proven by the fact that 

 the empty shells were able to retain then* shape for some time. 



THE NEWLY HATCHED LARVA. 



When first hatched the larva (PI. II, fig. h) is semiopaque white. 

 The extreme tips of the mandibles are the only parts which show 

 any color, and these are light yellow. The general j)roi)ortions of 

 the newly hatched larva are very much like those of the older ones. 

 They vary little in size. Their average length is 2 mai, and the 

 width is 0.27 mm. 



