20 BULLETIN 1357, U. S. DEPARTMENT OF AGRICULTURE 
moving backward through the opening, after which it crawled inside 
and began to chew and swallow small portions of the broken shell, 
consuming about one-fourth of it. About an hour later it turned 
around and chewed at the other end. After 70 minutes the head was 
still rather transparent but had become brownish. 
When observed at 10.15 a. m., specimen B was curled up in the 
shell, flexed dorsally at about the division of the thorax and ab- 
domen, and seemed to be pushing upward on the shell. No ruptures 
in the shell were visible at this time. The larva then straightened 
out and twisted itself around so that its mouth reached the place 
where the back had been pressing against the shell, where it had 
chewed an opening by 10.55 a.m. At “11.45 a.m. it again returned to 
its first position and was pressing with its back against the break in 
the shell, enlarging the opening. A wavelike motion, extending from 
the tip of the abdomen forward toward the head, accompanied the 
pushing and helped break open the shell. Following this the little 
larva straightened its head and thorax, keeping the abdomen in the 
same position as when pushing. The opening was Bei ten Ty not 
eee 
Fic. 8.—Strawberry rootworm. Lateral view of larva, enlarged 
large enough for the head to get out. At noon the larva, by curling 
the end of its abdomen slightly forward, shoved itself backward until 
its head could be thrust out through the opening made. At this time 
there was no differentiation in the color of the head and the body. 
LARVA STAGE ® 
The full-grown larve or grubs (fig. 8) are from 4 to 5 millimeters long and 
1.1 to 1.4 millimeters wide. They are entirely white except for the head and 
the dorsal surface of the prothorax, which are pale yellowish brown. The 
prothoracic segment, which is firmer in structure and bears only one fold, 
is leathery and smooth above and a little longer than the other segments. The 
remaining segments are each marked with three transverse dorsal folds, which 
terminate on the sides in large, low elevations, pointed ovate in form (the 
pointed ends being upward), one to each segment of the body excepting the 
head, prothorax, and anal segment. 
There are nine spiracles on each side of the body, the first Bes: than the. 
others and located between the prothoracie and mesothoracic segments, whereas 
the others are placed on the abdominal segments, except the last. They are at 
the lower ends of the ovate elevations mentioned above. Below the row of 
spiracles there is a row of prominent tubercles, one to each segment, forming a 
longitudinal groove between this row and the elevations above the spiracles. 
On each ovate elevation there is just above the spiracle a small mound from the 
center of which arises a seta. A similar seta arises from each tubercle of the 
first row. Below this row of tubercles is a longitudinal fold on each segment, 
5 The description of the larva is based on that given by Forbes (18, pp. 151-152). with 
some additions and modifications. 
