LIFE HISTORY AND HABITS. 



19 



(lition of the soil, a loose damp soil being selected by the adults in 

 preference to other kinds. 



Nearly all the eggs were placed in the first inch and a half of damp 

 soil, and the greater part of these about 1 inch below the line of 

 dampness. 



A small mite, which has been identified by Mr. Nathan Banks as 

 (Gamasus) Parasitus coleoptratorum L. (?), was commonly noted in the 

 soil with the eggs but was never seen destroying them. 



NUMBER AND HATCHING OF EGGS. 



Complete records for the eggs could not be obtained, so the lumi- 

 ber of eggs laid by a female of this species is still a question. One 

 female which had been isolated after fertilization laid 71 eggs before 

 death, and 11 were added by dissection, brmgmg the total to 82 

 eggs. Another female gave a total of 63 eggs by ovij)osition and dis- 

 section. Two others gave 61 and 52 eggs. Twenty-five dissections 

 gave the number of eggs as between 28 and 40, or an average of about 



A?S4K 



Fig. 4. — Diagram showing the period eggs ol the sugar-beet wireworm were in the soil, with temperature; 

 season of lOri, Compton, Cal. (Original.) 



34 eggs per individual. It is quite probable that 100 eggs or even 

 more may be deposited by a single female. 



Practically all the eggs hatch. In the laboratory over 94 per 

 cent of 5,000 eggs hatched successfully, even after they had been 

 handled and kept under artificial conditions. Those which did not 

 hatch were for the most part either allowed to dry out or were killed 

 by a fungus. Eliminating tAvo cages — the one which dried out and 

 th(> one in which the fungus appeared — it would be safe to say that 

 over 98 per cent of about 4,200 eggs which were kept under labora- 

 tory conditions hatched safely. 



There is an optimum zone, in so far as the degree of dampness is 

 concerned, for the hatchmg of the eggs. Some eggs kept in a dry 

 vial indoors, where it was not too warm, failed entu-ely to hatch and 

 after a time shriveled uj). On the other hand, the eggs which were 

 kept too damp were subject to a fungous attack. Water itself 



