36 



THE SUGAR-BEET WIKEWORM. 



Ill one field, which had a great many old l)eets on the surface, the 

 beetles were taken from under almost every one, and sometimes in 

 large numbers. It was a common matter to find from 30 to 70 

 adults under single beets, and as many as 243 have been found hiding 

 under one beet. Another favorite shelter was afforded by the old 

 beet tops (PI. XVIII) left in the field from the previous year's harvest. 

 In the field whicli adjoined this one there were few or no old beet 

 tops and beets for shelter, and here beetles were rarities. This field, 

 just the year before, suffered more than any of the surrounding fields 



from wire worm in- 

 jury, so there must 

 have been beetles 

 which developed from 

 the m a t u r e w i r e - 

 worms t h a t h a d 

 caused the damage. 

 In other fields, how- 

 ever, which had suf- 

 fered similar injury 

 but in wliich the old 

 beets had been al- 

 lowed to remain, 

 beetles were present 

 in large numbers. 

 There seems to be 

 only one explanation 

 for this fact, and that 

 is that the adults liad 

 emerged from the 

 cleaned fields and, not 

 finding any shelter, 

 had been obliged to 

 move to other fields 

 or be destroyed by 

 the birds. Tliis was further indicated by the fact that all the beetles 

 found in the clean fields were moving about. The state of affairs 

 was found to be the same in other fields aggregating over 600 acres, 

 where the conditions were similar. 



Fig. S.— Screen cage used in observing oviposition of adults of the 

 supar-boet wireworm under field conditions. (Original.) 



STYLES OF REARING CAGES USED. 



Several styles of rearing cages were used, but only a few will be 

 considered , The ones used indoors consisted of battery jars, flower- 

 pots, and flowerpots with lantern globes. The highest death rate 

 was found in the first , Ix'cause there was no drainage and the contents 



