80 



SOME INSECTS INJURIOUS TO TRUCK CROPS. 



mental cages [fig. 17], wliicli were covered with cheese cloth, hiul to be re- 

 covered with calico. They also make their way thi'ough the soil with little 

 difficulty. Experiments to determine this point consisted in burying them at 

 different depths, enclosed in tin cylinders. In two days the beetles appeared 

 through 2, 4, and G inches of loose soil, but did not appear from these same 

 depths where the soil was made compact by tamping. 



The egg. — A few eggs have been talc en on the hop roots about 4 inches 

 below the surface. Obviously, these are most difficult to find and can not be 

 detected at all without a magnifier. To more easily obtain the eggs and younger 

 stages, tin cylinders, 8 inches in diameter and 2 feet high, have been sunk to a 



depth of 8 inches in the 

 ground, some enclosing hop 

 vines and others in the 

 open field. Large numbers 

 of beetles have been liber- 

 ated in each of these, and 

 they will be taken up with 

 the soil intact in the tins in 

 two, three, and four weeks, 

 and the soil carefully ex- 

 amined for eggs and larvae. 

 Beetles taken in mating, 

 and enclosed in vials with 

 earth at the bottom, have 

 laid eggs in from eight to 

 ten days. 



The larva. — Larvae of what 

 the writer believes to be 

 this flea-beetle have been 

 taken from 2 to 4 inches 

 below the surface, both 

 around hop roots and in the 

 spaces between the vines 

 away from any hop roots. 

 While most of the larvie 

 have been taken about hop 

 vines, I think that they are 

 not restricted, in feeding, 

 to the roots of the hop ex- 

 clusively, since some have 

 been taken in spaces be- 

 tween the hop vines and 

 also because of the wide 

 distribution of the beetle, both in the United States and in the valleys of the 

 Chilliwack and Agassiz, away from any hopyards. Search about the roots of 

 the nettle and other plants growing along the borders and roadsides failed to 

 reveal any larvre. 



The pupa. — We have also taken pup.ne of what was considered this flea-beetle. 

 Transformation to the adult was, of course, necessary to establish this positively 

 and some of the pupse taken to the laboratory duly transformed. These were 

 taken about the hop roots 3 or 4 inches below the surface. 



Both larvae and pupae, when sought at the same time, were extremely scarce, 

 and sometimes an hour's search would result in finding nothing. Earlier in the 



Fig. 17.- 



-Breodiug and coutrol cage in place over a hill. 

 (Original.) 



