24 THE SUGAR-BEET WIREWOEM. 



inches below the surface, but as the soil in the rearing cages was 

 kept damp to the surface they would evidently be found deeper under 

 field conditions. 



Examination from time to time during the summer revealed no 

 startling changes. Growth was very slow, but the wireworms be- 

 came more active, and their skins a deeper yellow and noticeably 

 harder. 



APPROXIMATE LENGTH OF LARVAL STAGE. 



As the first larva? of this species were hatched from the eggs iii the 

 spring of 1912 there are no data concerning the complete life history 

 or even of the way the larvse pass their first winter. At the date of 

 this ^^Tithlg (Oct. 15, 1912), however, it seems quite evident that this 

 year's mreworms will turn out next sprmg to be the "small ones" 

 which are always noted commg up to feed during February and 

 March. 



At the time the beetles were being collected, in March, 1912, there 

 was no vegetation of any kind in some of the fields, and the wire- 

 worms, coming out from hibernation, were attracted to the old beet 

 roots which are found in greater or less numbers in all of the fields. 

 Nearly all larvae collected at this time, to the number of over 3,000, 

 were readily separable into two sizes. This has been reported before 

 by other investigators.^ The smaller ones appeared to be about 

 one-third grown, and very probably were the ones which had hatched 

 the preceding spring, and were consequently about a 3'ear old. The 

 larger ones showed more variation in size, occurring from three- 

 fourths grown to practically mature. These larvae, were probably 

 1 and 2 years older than those of the smaller size. That there is 

 a difference in age in the wireworms of this latter group is proved by 

 the fact that of 100 isolated during March only 17 pupated in the 

 period from July to September, and the remainder, some of which 

 at the time of writing (December, 1912), had recently molted, had 

 gone deep into the soil in the cages and seemed prepared to spend the 

 winter. Now, from the fact that none of these large larvae could 

 have come from eggs the preceding spring it seems very probable 

 that this species will uphold the contentions of most of the American 

 writers on this subject and spend three years in the larval state. To 

 be exact, it would be a trifle over three years, as Prof. F. M. Webster ^ 

 has pointed out, "the larvae hatching in the spring and pupating in 

 tlie late summer." Larvae have also been carried in the laboratoiy 

 from June, 1910, to April, 1912, without pupating, so it seems evident 

 that the larval stage could not be less than three years. 



1 Eleventh Hcporl on the Noxious, Beneficial and other Insects of New York. Ry Asa Fitch, M. T>., ISfifi. 



2 Underground Insect Destroyers of the Wheat I'lant. By V. M. Webster. Bui. 46, Ohio Agr. Exp. Sta., 

 1892. 



