THE MAIZE BILLBUG. 7 
curved, swelling ventrally from the third abdominal joint posteriorly, slightly 
recurved and rounded at anal extremity. Head large, oblong, obtusely angulate 
at base, sinuately narrowed anteriorly ; frontal margin with a shallow emargina- 
tion between the mandibles; upper surface with a median channel, the occipital 
portion deeply incised, with raised edges, continuing as a shallow impressed line 
to the middle of the front; on either side an engraved line, commencing upon 
the vertex, becoming deeper after crossing the branches of the Y suture, and 
terminating at the frontal margin in a bristle-bearing depression; sides and 
vertex with several long bristles arising in depressions; antennse rudimentary, 
occupying minute pits on the frontal margin at the middle of the base of man- 
dibles; ocelli a single pair, visible only as translucent spots upon the anterior 
face of the thickened frontal margin, outside of and closely contiguous to the 
antennze from which they are separated by the branches of the Y suture, a few 
pigment cells obscurely visible beneath the surface; clypeus free, transverse, 
trapezoidal, with faint impressions along the base and at the sides; labrum 
small, elliptical, bearing spines and bristles, a furrow each side of the middle, 
forming three ridges, so that the organ, when deflected, appears three-lobed ; 
mandibles stout, triangular, unarmed, with an obsolete longitudinal furrow on 
the outer face; maxille stout, cardinal piece transverse, basal piece elongate, 
bearing a palpus of two short joints, and a small rounded lobe, furnished at tip 
with a brush of spiny hairs, the lobe concealed by the labium; labium consist- 
ing of a large triangular mentum, excavate beneath, and a hastate palpiger, 
with a deep median channel; labial palpi divergent, separated by the ligula, 
of two joints subequal in length; ligula represented by a prominent rounded 
lobe, densely ciliate on the under surface. Thoracic joints separated above by 
transverse folds; the first wider, covered above by a transverse, thinly chitinous 
plate; the two following similar to the abdominal joints; abdominal joints 
forming on the dorsum narrow transverse folds, separated by two wider folds, 
the anterior fold attaining the ventral surface, the second fold confined to the 
dorsum, eighth and ninth abdominal joints longer, excavate above, without 
dorsal folds; beneath, the first three joints contracted, the succeeding joints 
enlarged, the terminal joint broadly rounded, with anal opening upon a fold at 
its base; sides of each joint presenting numerous longitudinal folds; stigmata 
very large, nine pairs; the first on the anterior margin of the prothorax, low 
down upon the sides; the remainder upon the sides of the first eight abdominal 
joints, above the lateral prominences, beginning upon the first joint at the 
middle of the side and gradually rising to a dorsal position upon the eighth 
joint; thoracic and last abdominal pairs large, oval; the intermediate pairs 
smaller, elliptical; all with chitinous margins of dark-brown color. The notice- 
able features of this larva are its cephalic vitte, and conspicuous spiracles. 
Upon issuing from the eggshell the young larve are about 5 mm. 
long and 2 mm. thick. They at once begin feeding on the tissues of 
the young corn at the bottom of the egg puncture (fig. 7, >), direct- 
ing their burrowing inward and downward into the taproot. When 
they finish eating the tender parts of the taproot they direct their 
feeding upward, continuing until full grown, allowing the lower 
portion of the burrow to catch the frass and excrement (fig. 7, 2). 
This burrowing of the taproot of the young growing corn plant is 
disastrous to the root system (PI. I, figs. 1, 2); the roots, first dying 
at the tips, soon become of little use to the plant, allowing it to die 
or to become more or less dwarfed (PI. IIT). The corn plants shown 
