Se Fe Se ae 
8 DEPARTMENT BULLETIN 179. 
THIRD INSTAR. 
Length 3.08 to 3.19 mm.; width of thorax 1.925 to 2.085 mm.; width of abdo- 
men 2.365 to 2.805 mm. 
Dorsally: Head black, finely punctate, slightly pubescent; eyes black, promi- 
Fic, 7.—The grain bug: Nymph, third 
Much enlarged. 
nent; antenne 1.925 to 1.98 
mm. in length, black, two termi- 
nal segments very finely pubes- 
cent. Thorax black with dis- 
tinct tinge of green, coarsely 
punctate; “shelf” white dur- 
ing early stage of instar, later 
becoming orange in color. Abdo- 
men dark green and bearing 
approximately the same mark- 
ings as later stages of preced- 
ing instar, and black coarse 
punctations; segmentation em- 
phasized by black lines in this 
and in the remaining nymphal 
instars; “ shelf’ orange color. 
Ventrally: Head and thorax 
green. Abdomen pale green, a 
black cireular area on each of 
the four terminal segments; 
anal opening black. These 
black areas persist on the venter 
of the remaining nymphal instars. “Shelf” orange on both thorax and abdo- 
men. Rostrum green, extending slightly more than one-half length of venter. 
Legs: Coxee, trochanters, and femora green; tibiz and tarsi brown. 
Described from 7 specimens. 
FOURTH INSTAR. 
Length 5.2 to 6.6 mm.; width of 
thorax 3.1 to 3.75 mm.; width of 
abdomen 3.8 to 4.9 mm. 
Dorsally: Head pale green, finely 
punctate; eyes reddish black, not so 
prominent as in preceding instars; 
antenne 3.4 to 3.7 mm. in length, 
dark brown or black. Thorax pale 
green with darker coarse puncta- 
tions; wing pads visible as slightly 
raised areas on both sides of thorax; 
“shelf” white with a _ red-orange 
edge. Abdomen pale green; puncta- 
tions numerous, coarse and darker 
green in color; a narrow yellow 
transverse band occupying one-half 
median portion of abdomen on an- 
terior border, and posterior to this 
8.—The grain bug: Nymph, fourth 
instar. Much enlarged. 
band the mid-dorsal section occupied by a short narrow yellow band, four 
circular areas of the same color, and two brown crescentic projections bear- 
ing the scent glands; black coarse punctations more numerous than in preced- 
ing instar; “shelf” white with red-orange edge. 
