33 
ing there lands of various previous history. An older article by Mr. J. 
Pettit* gives a full acount of its attack on wheat. 
The length of time passed by this species in the larva, or wireworm, 
state cannot be given with certainty. Mr. J. Pettit, of Ontario, who 
was the first to rear it from the larva to the adult, was of the opinion 
that the larval state did not last longer than three years.t Messrs. 
Comstock and Slingerland, in their w ork on wireworms at the Cornell 
University Experiment Station, 1889-1891, from extensive and careful 
breeding-cage experiments—one at least of which co1tinued through 
two years and two months—arrived at the same conclusion. They also 
ascertained that as the summer advanced the larve became gradually 
less destructive, and that by November 1 (probably earlier in the fields) 
they cease feeding and go deeper into the ground, where they wemain 
without food for five or six months. It is early i in spring, when they be- 
gin to eat again after this long fast, that the greatest damage *s done to 
crops. 
Larve become full grown and pupate in July, in earthen cells. The 
change occurs a few days after these cells are formed, and pup are 
most abundant about the middle of July. Adults may be found by the 
end of this month, and by about September 1 all the pupe have changed 
to beetles. For a ae days after the change they are yellowish ie in 
color, and nearly as tender as pupe. Before winter, however, they have 
become hard and normally colored. In Comstock’s experiments, the bee- 
tles passed the winter in their earthen cells, none coming to the surface 
the same fall unless their cells were injured. Adults thus disturbed did 
not form new cells, but worked their way to the surface ana soon died. 
In April the greater number of the beetles emerge from the earth, 
though we have taken them almost continuously from March ?2 to the 
middle of July. They are most active in the evening or at night. 
Description. Larva. (Plate V., Fig. 5 and 6.) —“The new ly “hatched 
larve must be very small, and, according to European writers, they 
grow very slowly. The smallest larve of the wheat wireworm we have 
seen were about 4 mm. in length. All variations in size occur at the 
same time up to a full grown larva, which measures from 16 mm. to 19 
mm. The larve are quite slender, cylindrical, somewhat fiattened on 
the venter, sparsely hairy, and of a waxy yellow color, lighter at the 
sutures. The anal segment tapers gradually to a subacute brown point, 
and bears on the dorsal aspect, near the cephalic border, two large con- 
spicuous, brown, eye-like depressions resembling the breathing pores. 
By these, the wheat wireworm of any size may be readily separated from 
any other species which we have found infesting fields.” f 
Pupa.—<The pupa resembles the imago in many of its char acters, 
being, however, about one fourth longer, and in the abdominal region 
more slender, the only differences of moment being the following: 
EI Oon ints. .ViOls eVe= Ole 2) eps oe 
7 “Description of the Wheat Wireworm.” Can. Ent. Vol. IV. (1872), pp. 3-7. 
This article contains figures and descriptions of the larva and pupa by Dr. Horn, 
from specimens reared by Mr. Pettit. 
+ Comstock and Slingerland, in Bull. 33 Ent. Div. Agr. Exper. Station, Cornell 
Wmiv. p 252. : 
