28 



THE SUGAR-BEET WIREWORM. 



Avaleiecl lojjculaily, except on two occasions, (luring the late summer 

 of 1911 and was then allowed to become quite dry. As the larvae 

 were killed by the drying soil they were removed so that they would 

 not furnish food for the survivors. On September 12, 1911, the 

 cage was again examined and only one larva was found alive. Two 

 dead ones were found near the surface m the tlry earth, and they 

 had probably been killed by the drying out of the soil. This cage 

 was then watered regularly and examined at intervals. The larva 

 was still alive and active on April 15, 1912. During the latter 

 part of April the cage, which was kept in the outdoor insectary, was 

 blown over by the wind and broken. Before it was noticed the 

 soil had dried out to such an extent that the larva was dead. An 



Fig. 7. — Diagram showing length of life of sugar-beet wireworm without food. (Original.) 



exam'mation of the channels through tlie cage showed that the wire- 

 worm had been quite active up to the time of its death. While 

 those larvae might have secured a little food during the earlier part 

 (»r the experiment they could not have done so later, as they weie 

 ( iu'cked up and removed when they died. In this experiment 

 seven wirewornis lived over a year without food, and one almost two 

 years, as shown in the following diagram (fig. 7). 



These wnreworms did not grow noiTnally, for when the last one 

 died after being in the cage two years it was less than half size. This 

 larva should have ])Uj)ated that fall, as it was at least a year old when 

 the experiment be^gan, and therefore should have been mature. 



