82 



lYz mm. In other words, these larvae varied in age from those jusi 

 hatched to others virtually three-fourths grown. 



The next inspection was not made until the 9th of July, when 

 larvae were found varying from 2 mm. to 12 mm. in length — the last 

 full grown. On the 12th of July four pots contained larvae from 4 mm. 

 long to the maximum size. Cautious search of these pots was made for 

 pupae every second day from July 12 to the 20th, but none were found. 

 On the 25th of July a thoro examination of all the pots disclosed four 

 adults in the earth (the pale color of which showed that they were 

 but recently transformed), together with three pupae, and larvae of 

 various sizes from 5 mm. to 12 mm. long. Some of the oldest larvae 

 were thickening and shortening up preparatory to pupation. By the 

 following day three of them had pupated, and the next day three 

 more. Attempts to carry these pupae thru separately to the imago 

 stage, with a view to determining the length of the pupal period, were 

 disappointed by the death of the pupae, probably thru some fault of 

 management. The experiment was interrupted on the 10th of August, 

 and no further data were obtained. 



It will be noticed that we have here a much earlier start in the 

 development of the root-worms than in the preceding experiment, a 

 fact probably due to the miscellaneous character of the material ob- 

 tained in collections of the soil from the infested corn-field. 



Another imperfect experiment. No. 2810, may be worthy of men- 

 tion by way of verification. This was based on eggs taken from the 

 earth in a corn field, September 15 to 17, 1905, and placed with a little 

 dirt in a perforated tin box, three inches in diameter. This was buried 

 in earth in an ordinary flower-pot, and kept thru the winter at ordinary 

 outdoor temperatures. On the 6th of March, 1906, these eggs were 

 seen to be in good condition. They were inspected daily from March 

 31 to June 19, at which time a root of the corn plant growing in the 

 pot was found to be infested and slightly injured by a Diabrotica larva 

 only 3 mm. long, and evidently hatched quite recently. 



This experiment was interrupted July 1, and nothing further 

 came of it. 



An additional item of some interest, as showing the ease with 

 which Diabrotica eggs may be obtained at the proper season of the 

 year, is given in a note made by Mr. E. O. G. Kelly, my field assistant 

 in 1905. September 16 of that year he put into a bottle, with green 

 corn-silks, about a dozen Diabroticas caught on sunflower blossoms, 

 and four days later found that they had deposited some four hundred 

 eggs on the contents and sides of the bottle. Whether these were 



