206 TRANS. ST. LOUIS ACAD. SCIENCE. 



than long with the sides bulging and with two horns on top diverging 

 at right angles from each other, and in length about one-third the width 

 of head, each ending in a prominent, more or less acute, bifurcation, and 

 giving out three lesser branches from the sides : also with a prominent 

 lateral, slightly decurved and acute spine, a lesser one above and below 

 this, and two on top between the bifurcate horns. The color is quite varia- 

 ble, sometimes being entirely dark-brown, but more often pale, with the 

 jaws, sutures, ground of ocelli, and tips of horns, dark. It is furnished 

 with a few short hairs. In the third stage there is but little change ; joints 

 5-9 are proportionally somewhat more enlarged, and the spines on the head 

 proportionally increased in length. The papillse become more prominent 

 and numerous, and the transverse yellow line connecting the subdorsal lines 

 across the anterior wrinkles as well as the supra-stigmatal line become 

 less continuous. The fourth and fifth stages are similar, the horns on the 

 head are lengthened but the forks and the spines shortened, while the trans- 

 verse stripes and the supra-stigmatal line are generally interrupted. The 

 mature larva may be thus described : 



Average length, 1.15 inches. Head as broad or broader than long, the 

 cheeks bulging, the horns half as long as head, slender, the bifurcations 

 reduced and rounded, the spines not prominent; shallowly punctate and 

 sparsely pubescent; color either green with faint touch of brown on jaws, 

 at ocelli and tips of horns, or brown-black with more or less pale color, 

 and always four stripes in front, two short ones near ocelli, and two others 

 running by the side of epistoma and tapering up the horns. Body bright 

 pea-green, very small on joint 1, enlarging in middle, and tapering to ex- 

 tremity, which ends in two horizontal, slightly diverging anal horns. Each 

 joint with about four annulets. A medio-dorsal series of yellow spots the 

 width of first annulet; a pale white and yellow stripe, thickest at sutures, 

 running each side of dorsum to tip of anal horns; a series of pale, oblique 

 supra-stigmatal marks containing a lead-colored impressed point; and a 

 straight substigmatal line. Covered with numerous irregular pale papil- 

 lae, largest on yellow parts. Ventrally more smooth, glaucous, and with 

 soft colorless hairs. Legs pale, the pads of prolegs dusky. The supra- 

 stigmatal oblique dashes are sometimes connected to form a wavy line, and 

 there are are other minor variations of color and markings. 



Chrysalis — General surface faintly aciculate. Dorsum narrow-edged, 

 in outline strongly arched on abdominal joints 3-8 (6-1 1 of body exclusive 

 of head) ; straight and falling at an angle of about 130 from 3rd abdomi- 

 nal joint to metathorax, thence rising at the same angle straight to middle 

 of mesothorax, and falling again at an angle of about 120 direct to head. 

 From a dorsal view the outline broadens regularly from anal extremity to 

 wing-sheaths, is parallel thence to the region of the metathorax, then 

 bulges and is broadest at the wing-shoulders, and gradually decreases 

 again to the ocellar tubercles. The inferior surface forms a straight line 

 from the eyes to the tip of the legs, then makes a slight upward curve and 

 ends in abutton or cremaster, which represents the anal larval prolegs and 



