THE BOUGH-HEADED CORN STALK-BEETLE 19 



The head is rather short, its median length being about half its maximum 

 width. Its surface is marked by numerous transverse, undulate rugulae (fig. 

 8) which are reduced to minute granulations on the front half of the clypeus 

 and disappear on the occiput, which is quite smooth, except for a few sparse, 

 shallow punctures. The clypeus has strongly oblique sides which are conspicu- 

 ously margined and elevated. Immediately in front of the clypeal suture the 

 head is crossed by a rather low, transverse ridge, or carina, which is broadly 

 interrupted in the middle. The apical margin of the clypeus is almost trun- 

 cate and rather short, being only about one-fourth the width of the base. It 

 is dorsally reflexed and crested, the crest being interrupted in the middle by 

 an oblique sinus, which separates the two conical processes — the so-called 

 " teeth " — arising from the crest. These " teeth " in fresh specimens are rather 

 high and sharp, but in old and worn specimens are frequently reduced to mere 

 stumps. The mandibles are visible from above beyond the sides of the clypeus, 

 and are very unequally bidentate, the anterior tooth, which is upturned at the 

 apex, being much larger than the short, obtuse, posterior one. 



The pronotum is distinctly wider than long, and about twice as wide as the 

 head. Its sides are broadly and evenly arcuate and narrowed slightly an- 

 teriorly, the surface being smoothly and uniformly convex, bearing numerous 

 coarse, annular punctures which are somewhat sparsely distributed through- 

 out but rather more crowded on the sides than in the middle. The anterior 

 and lateral borders are clearly margined, the posterior plain and feebly bi- 

 sinuate. The antero-lateral angles are sharply produced anteriorly, while the 

 postero-lateral ones are broadly rounded and obtuse-angulate. 



The scutellum, although rather small, is quite distinct, the surface being 

 smooth, except for a few minute punctures. 



The elytra are but slightly longer than their combined width, which is not 

 obviously greater than that of the pronotum. Each is longitudinally traversed 

 by a number of slightly impressed, double rows of rather coarse, circular 

 punctures, these giving the elytra a somewhat striate appearance (fig. 7). 

 Anteriorly these punctures are frequently confluent and variolate. Outside 

 of the double rows of punctures, the entire surface of the elytra is covered with 

 numerous closely set and irregularly distributed punctures, which, for the 

 most part, are essentially similar to those forming the double rows, but are 

 reduced on the sides and apical half to minute, punctate impressions. 



The stridulating organs on the inner surface of the elytra are very feebly 

 developed. 



The labium (fig. 8) is considerably longer than wide, and is appreciably nar- 

 rowed at its apical end, which is feebly bilobed and marked by sharply elevated 

 lateral margins situated under the insertion of the palpi; the basal half is 

 rather strongly convex, without lateral margins, and bears on the sides nu- 

 merous long stiff bristles, which are largely lacking toward the center. 



The prosternum (fig. 8) bears a stout, erect, cylindrical, postcoxal process 

 or spine, the apex of which is almost flat and occupied by a smooth, padlike 

 surface, the hind margin of which bears a conspicuous, radiating fringe of 

 long, stiff bristles. 



The surface of the mesosternum and metasternum is nearly smooth, or at 

 most but very sparsely and indistinctly pilose. The metasternum bears nu- 

 merous shallow, circular punctures, larger and coarser on the side than in the 

 middle, each of which is frequently provided with a minute, barely visible 

 bristle or seta. The mesepisternum has its surface somewhat rugulose and 

 bears a rather sparse covering of stiff hairs. 



The forelegs are relatively stout and are adapted for digging. The tibiae bear 

 on the hind margin four distinct, toothlike projections, three being long, stout, 

 and acute ; the fourth, or uppermost, much smaller and decidedly obtuse. 



SEXUAL CHARACTERS 



The last ventral segment of the male (fig. 9) bears near the anal 

 margin a transverse fringe of short, stiff hairs which is broadly in- 

 terrupted in the middle ; back of this interruption or hairless interval 

 there is a short postanal fringe. In the female (fig. 10) the same 

 character is also present, but there is no median break, the fringe 

 being continuous. 



