LIFE HISTORY AND HABITS. 23 



placed ill the center of a large petri dish. Witliin 10 iniiuites all the 

 wirewornis were under it. This experiment was repeated by using a 

 piece of damp cardboard the size of the beet slice and again timing 

 the wireworms. In this test all the larvae finally gathered under the 

 cardboard to escape the light, but a longer time was required before 

 this took place. These tests were repeated several times as checks 

 and always gave the same results, so it is evident that the larvae are 

 able, to a small extent, to locate food. 



The larvae begin feedmg noticeably, though lightly, very soon 

 after hatchmg. A fresh slice of sugar beet was placed in the cage 

 every day, and w^hen each slice was removed the mmute black feedmg 

 marks could be noticed. The depressions made by the feedmg could 

 be made out only with a hand lens, but the black stam, so character- 

 istic of wu'eworm injury, had spread out and was quite conspicuous. 



The wu'eworms grow quite rapidly durmg the first two or three 

 weeks, and it might be added that this is the only tinie in their long 

 larval life when theu" growth is apparent. They approximately 

 double in size in this tune and then remam about the same size until 

 they molt. At the time of their first molt they take a sudden jump 

 in size and froiiv this time on their growth is very slow. 



An attempt was made to trace the molts with these wireworms, 

 but unfortunately it had to be abandoned. The death rate in the 

 exposed cages was so high that it soon became apparent that none 

 could be brought entirely through in this manner. Added to the 

 difhculty was the fact that since their time of molting was so UTegular 

 only a few^ could be kept in a single cage. After about a thousand 

 larvae had died in these cages it was concluded that it was impossible 

 to carry the observations to completion with the forms of rearing 

 apparatus at hand. The cast skins of the larvae could not be found, 

 owing to their small size and transparency, and the only molts that 

 could be traced were in the case of certam larvae which mcreased in 

 size quite noticeably overnight. The increase in the width of the 

 head was found to be the best test. 



From time to tune the soil in the flowerpots containing the bulk of 

 the wireworms was carefully examined to see whether anything could 

 be learned concerning the feeding habits of the larvae under natural 

 conditions. In every case the larvae were found scattered rather 

 generally through the sod, and as many of them were found around 

 the edges of the pot as directly around the beet root. Since the root 

 hairs were scattered pretty generally through the soU it seemed prob- 

 able that the lai'vae fed on them. This was further indicated by the 

 fact that no feeding marks could be found on the mam beet root. 

 At any rate it is safe to say that, from the standpoint of injury due 

 to their feeding, the wireworms during the first year of their lai'val 

 life may be disregarded. Larvae were generally found from 1 to 3 



