﻿THE GRA^ISTAKY WEEVIL 



11 



THE LARVA 



(Fig. 7, ato d, g to j) 



Mature larva (/) 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 (b) Ught 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 bej^ond the middle. Sutural margins irregu- 

 lar or sinuate. Frons provided with five pairs of large setse, 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 setse 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, li) entire, tip 

 obtuse, dorsal and ventral surfaces smooth, lightly chitinizcd, dorsal surface with 

 a longitudinal row of six j>lain stout sof,;i', tip with two short and two longer setae. 

 Maxillary palp extending slightly beyond mala, two-jointed, proximal joint thick 

 androunrled, f)earingasinglf;Keta noarapi'x; distal joint lingcirlike, bearing several 

 terminal papilla;. Then; are thrdc odicr seta; on maxilla, two located on the 

 vaginant membrane between [ialpns and pulpifcr and one, stouter and longer, 

 midway between palpus and cardo. 



Mentum, snbrnc:ntnrn, and maxillnry articulating area fused into a fleshy 

 region l^earing three [mirs of stout sel.c Euiabiu/n posteriorly enforced !>>' a 

 median triangularly bent chitinization. Between the palpi a small slightly 



Fig. 6.— View of pill box, IJ^ 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 



