124 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



varied considerably in the two years under observation. The follow- 

 ing table shows the variation: 



Incubation Period 

 Date 



1914. 

 1915. 



A single female was observed to lay 59 eggs, the average for 41 

 females for an entire summer being 22.9. 



Egg-laying begins about the latter part of May and continues, in 

 late seasons, until the first week of August. Individual females will 

 lay eggs, intermittently, over a period of 68 days. Eggs are, as a rule, 

 not laid daily by individual females. Frequently, they are deposit-ed 

 for two or three consecutive days followed by an intermission of a few 

 days. Six per day was the largest number of eggs to be laid by a 

 single individual. 



Eggs require moisture, for hatching, which is furnished by the tissues 

 of the plant. Eggs kept on damp soil hatched readily. Under labo- 

 ratory conditions they were easily incubated in moist vials or on 

 freshly cut pieces of corn stalk. 



Full}' developed eggs dissected from recently killed adults always 

 failed to hatch. These females, at the height of the egg-lajdng period, 

 were never found to contain more than six ripe and three immature 

 eggs at one time. 



A few Q\a,ys before hatching, body segments of the growing larva can 

 be seen through the shell. Frequently, the brown coloration of the 

 head is noticed, especially in late hatching eggs. 



Larva 



In hatching, the egg splits at the end containing the caudal region of 

 the larva and along one side. By continued twisting, the young, 

 footless larva backs its way out and finds itself surrounded by an 

 abundance of food. At this time it is scarcely larger than the egg and 

 is white in color, except the head which is a chestnut l^rown. Fre- 

 quently larvae, hatching after a short incubation period, are white 

 with only the mandibles of a brown hue. In the latter case, the 

 whole head completely darkens soon after emerging from the shell. 



The young larva at once begins to work up and down in the stalk, 

 leaving the burrow behind it filled with castings. Before pupation, 

 part of these castings are used to construct a pupal cell by compacting 

 them against the walls of the burrow near the tap-root. The larva, 

 if head downward, reverses its position, assumes a quiescent stage for 

 two or three days, undergoes a final moult and pupates. This insect 

 was observed to moult five times. Three or four larvse mav work in 



