35 
H 
Imago. (Plate II, Fig. 3, f, g, li and i). Female. Length of 
ly, 2.8 mm.; expanse of wings, 4 mm.; greatest width of front 
ig, 0.7 mm.; antennae, sub-clavate, three-fourths the length of 
rax; whole body (with the exception of metanotum, which is 
ily punctate,) highly polished and sparsely covered with long 
rs toward end of abdomen; abdomen longer than thorax, and 
iter. Color, pitchy-black; scape of antennae, occasionally a small 
ch on the cheek, mesoscutum, femoro-tibial articulations, coxae 
>ve and tarsi (except last joint) tawny; pronotal spot large, oval, 
l pale yellowish in color; wing veins dusky yellow and extending 
>eyond middle of wing; sub-marginal three times as long as mar- 
al; post-marginal very slightly shorter than marginal, and stigmal 
) shorter than marginal. 
)escribed from twenty-four specimens. Of these twenty-four 
cimens, only one was fully winged; two were furnished with hind 
gs only, and the rest were wingless. Male unknown. 
,arva. (Plate II, Fig, 3, a, b, c, d and e). Length, 4.5 mm. 
irly -J- inch); of the shape indicated in Fig. 3. Color, pale yel- 
; mouth parts brownish. Antennae appearing as short, two- 
ted tubercles. Mandibles with two teeth. Venter furnished with 
double longitudinal row of stout bristles, a pair to each joint. 
;h joint bears also, laterally, a short bristle. Stigmata pale, 
ular; ten pairs, one on each of joints *2 (mesothoracic) to 11.” 
} upa. (Plate II, Fig. 4). The mature pupa is 3 mm. in length 
.8 mm. in transverse diameter. It is of a wasp-like form, and 
srs but slightly from the wingless imago, except that the legs 
antennae are applied closely along the under surface and sides 
he thorax and abdomen, and are inclosed in a thin, transparent 
icle. The general color is jet black, and the various spots and 
•kings of the imago are visible through the pupal envelope. This 
i fact so thin that it does not conceal even the hairs upon the 
omen. 
il A' 
LIFE HISTORY. 
s is clearly apparent from the foregoing, this insect is unques- 
ably single-brooded, the eggs doubtless being laid upon the wheat 
^pnl and May. The young larvae penetrate the stem, develop 
mature within the straw, commence to transform to pupae as 
y as October, and apparently complete their transformation 
>re spring. In March and April the perfect insect emerges, 
iliar seasons and exceptional conditions having, however, the 
nary effect to retard or hasten the transformation. 
ur own observations upon the life history of the species fully 
Irm the latest conclusions of Profs. Riley and French. Early 
uly the larvae were found in the wheat stubble and straw near 
Quoin, Anna and Villa Ridge, in Perry, Jackson and Pulaski 
ities, in Southern Illinois, and numbers of specimens were sent 
3 to the Laboratory, where they were placed in breeding cages 
f kept without especial treatment, at the ordinary temperature of 
air, during the summer, fall and early winter. When examined 
anuary, all the larvae still remaining unchanged were dead, and 
! Fe living Isosomas were in the pupa form, with the exception 
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