THE GRANARY WEEVIL 
11 
THE LARVA 
(Fig. 7, a to d, g to 
J) 
Mature larva (f) 2.5 to 2.75 mm. in length. A pearly white, fleshy grub, very 
thick bodied, the ventral outline being approximately straight, whereas the dorsal 
outline is almost semicircular. Ten abdominal segments; ninth small, tenth 
reduced, eighth and ninth forming a sort of pygidial plate. 
Head (6) light brown in color, the anterior margin and mandibles much darker. 
Head longer than broad and somewhat wedge shaped, the sides broadly rounded 
from middle to apex, which is slightly angular. Sides nearly straight from middle 
to the anterior angles, and lateral area with an oblique, longitudinal, lighter 
stripe or area. 
Epicranial and frontal sutures distinct and light in color; also two oblique, 
longitudinal, light stripes rising from frontal sutures and coalescing with epicranial 
suture near base of head. 
Frons subtriangular, with a distinct, dark, median line indicating the carina 
running from the posterior angle to beyond the middle. Sutural margins irregu- 
lar or sinuate. Frons provided with five pairs of large setae, the sutural margins 
each bearing a large seta. 
Clypeus attached in front of 
frons and broadly transverse, 
broad at base, sides narrowing 
toward the apical angles, slightly 
longer and broader than labrum, 
and bearing on epistomal margin 
two fine setae on each side. 
Labrum (c) distinctly broader 
than long, with two small lateral 
and a larger, rounded, median 
lobe. Labrum provided with 
six large dorsal setae and two 
sensory spots, two marginal, 
short, thickened setae on each 
lateral lobe, and six similar 
marginal setae on median lobe. 
Each epicranial lobe bearing 
the following setae: One close to 
posterior angle of frons and lo- 
cated within the oblique, longi- 
tudinal stripe rising from the 
frontal suture; one very small 
seta posterior to this and near 
occiput; two anterior to it on 
disk of epicranium; two opposite 
middle of frons; one opposite 
middle of mandible; one opposite 
hypostomal angle of mandible; and one on hypostoma near base of mandible. 
Eye represented by a single ocellus. 
Antenna a fleshy two-jointed appendage located at the lateral angle of the 
frons, first joint broad and short, second slender and short. 
Mandibles (d) stout, triangular, with the apex produced into a broad apical 
tooth; inner edge toward the apex provided with a subapical tooth and a small 
medial tooth; no molar part. Dorsal area of mandible provided with two stout 
setae set apart. 
Maxilla with cardo present and distinct. Maxillary mala (g, h) entire, tip 
obtuse, dorsal and ventral surfaces smooth, lightly chitinized, dorsal surface with 
a longitudinal row of six plain stout setae, tip with two short and two longer setae. 
Maxillary palp extending slightly beyond mala, two-jointed, proximal joint thick 
and rounded, bearing a single seta near apex; distal joint fingerlike, bearing several 
terminal papillae. There are three other setae on maxilla, two located on the 
vaginant membrane between palpus and palpifer and one, stouter and longer, 
midway between palpus and cardo. 
Mentum, submentum, and maxillary articulating area fused into a fleshy 
region bearing three pairs of stout setae. Eulabium posteriorly enforced by a 
median triangularly bent chitinization. Between the palpi a small slightly 
Fig. 6.— View of pill box, 1J4 inches in diameter, showing 
three exit holes bored by adults of the granary weevil in 
escaping from box. Cereal cartons may be thus opened 
to the attack of cereal pests 
