80 
SOME INSECTS INJURIOUS TO TRUCK CROPS. 
mental cages [fig. 17], which were covered with cheese cloth, had to be re- 
covered with calico. They also make their way through 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 6 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 taken 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 youngei 
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 witl 
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 larvae 
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 larvae. 
The pupa. — We have also taken pupae of what was considered this flea-beetle. 
Transformation to the adult was, of course, necessary to establish this positively 
and some of the pupae 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. — Breeding 
and control cage in place over a hill. 
(Original.) 
