130 On the Life History of " Wlreivorms" 



as insecticides, several instances of the power of the larvae to withstand 

 starvation have also been noted. In one case, the larva was evidently 

 affected by the insecticide, which was not of a concentration sufficient 

 to kill it. Treated on the 21st June it still remained, three months later, 

 in much the same condition as immediately after treatment. It was 

 supplied with pieces of potato, but these were not eaten and eventually 

 the larva died — whether from the effect of the insecticide or from 

 starvation could not be ascertained. 



Larval Agriotes can withstand immersion in water for a very long 

 time. In glazed pots which have remained filled with rainwater for at 

 least a few days, they have afterwards been found alive. Bierkander(i7) 

 found they could live in water for four days, but Del Guercio(8) found 

 that death only took place after twenty to thirty days' submersion and 

 that, as he points out, at a time (June — July) when metabolism may 

 be considered at its height. 



Graf ((13) at p. 27) notes that some of the beet fields which have 

 suffered the most from the attacks of Limonius californiciis are those 

 which almost every year are quite thoroughly flooded for two or three 

 days. It appears therefore that irrigation for any reasonable period is 

 hardly likely to have any controlling effect. 



It has been stated by Del Guercio(8) that the larvae (of A. lineatus 

 and A. obscurus) feed during the winter between October and March, on 

 decaying vegetable matter and it is probable that such is often the 

 case. When grass-land has been newly ploughed, wireworms may be 

 found, in winter, still in the sod at or quite near the surface, even in hard 

 weather, provided that the sod remains sufficiently damp. They have 

 also been found repeatedly in winter, when digging in the sod heaps 

 mentioned above or on grass-land, amongst the roots of grasses growing 

 on the surface, even during the continuance of frost and snow. Such 

 larvae may be contracted and sluggish at the time, but appear to suffer 

 no permanent damage and revive quickly when brought under milder 

 conditions. At the same time that these larvae are found near the sur- 

 face on grass-land, others may be found at considerable depths below. 

 Thus, for example, in a hole dug to a depth of 31 inches in one of the 

 sod heaps at the end of December, 1917, 14 Agriotes larvae were taken. 

 Of these nearly half were taken amongst the roots of plants growing 

 on the surface or in the first spit (9 inches) of soil, but the remainder 

 were found lower, at depths from the surface of 11 down to 24 inches. 



In the case of arable land, which has not been recently ploughed 

 out of grass, the larvae are not found near the surface in winter, unless 



