PAPILIOXIDAE : RHODOCERIDI. 1835 



ZERENE HUBXER. 



Zerene Hlibn., Verz. bek. schmett., 97 (ISIG); Megonostoma Reak., Proc. ent. soc. Philad. 

 — Scu(]ii.,Proc. araer. acad. sc, x: 291 {1875). ii: 356 (1863). 



Imago. Head rather large, front quadrate, nearly flat, the lower half slightly pro- 

 jecting, slightly broader above than below, tlie upper part bent at an exceedingly broad 

 angle with the lower, furnishing a somewhat depressed field for the antennal pits which 

 are separated by their own width and reach behind the fine, carinate, erect edge of the 

 broad and mesially tumid vertex. Eyes large, full, naked. Antennae about as long as 

 the abdomen, composed of thirty-two joints, the last double, of which about nine form 

 the very gradually increased, abruptly terminated, cylindrical club, which is about 

 twice as broad as the stalk, with indistinguishable proximal limits, not tapering 

 distally, the largest joints (except the double apical joint) half as broad again as long, 

 the longest joints of the stalk nearly three times as long as broad. Palpi small, short, 

 compressed, compactly clothed, the middle joint compressed, regularly arcuate, equal, 

 fully five times as long as broad, the last stout, oval, not much longer than the breadth 

 of the middle joint. 



Fore wings slightly falcate, the costal margin being well arched apically, the apex 

 angular and the outer margin straight or even slightly excised above ; inner margin full 

 in its basal half. Subcostal nervure with three branches, the last forked and originat- 

 ing nearer the second than that the first, the second arising at the tip of the cell; the 

 latter less than half as long as the wing and about three times as long as broad. Hind 

 wings as in Enrymus, though somewhat longer. 



Legs rather slender, the fore legs of the female differing from those of the male only 

 in their greater length. Fore femora (comparisons with male only) as long as hind 

 tibiae, more than half as long again as the fore tibiae, which equal the first joint of fore 

 tarsi ; the first joint of fore tarsi equalling the rest together. Hind femora two-thirds the 

 length of the tibia which is a fifth longer than the first tarsal joint; the latter longer 

 than the next three joints together, the fifth as long as the third. Claws very delicate, 

 compressed, elongate, slender, gently arcuate, strongly heeled, slightly divaricate, 

 cleft nearly to the heel, very finely pointed. Paronychia simple, forming a moderately 

 stout, triangular, tapering and pointed lobe, closely appressed to the claw, reaching 

 but little beyond the cleft and united at base beneath. 



Egg. Fusiform, nearly three times as high as broad, largest a little below the mid- 

 dle, tapering more rapidly to the base which is about half as broad as the middle, 

 than to the very slender, bluntly rounded top, with a considerable number of slightly 

 and equally raised vertical ribs. 



Caterpillar at birth. Dermal appendages of the body Indian-club shaped or long 

 wine-glass shaped, nearly twice as long as the sections on which they are seated, but 

 not more than a third as long as the segments, arranged in the following series, one to 

 a segment in each : a laterodorsal on the anterior section ; a supralateral series, 

 scarcely behind the middle of the segments; a suprastigmatal, scarcely before the 

 middle of each segment; and an infrastigmatal series, two to a segment. 



Mature caterpillar. Closely agreeing in general appearance with Eurymus, but 

 with a smooth, lenticular, suprastigmatal disk on the second and third thoracic seg- 

 ment. 



Chrysalis. Resembling that of Eurymus, but with the mesonotum less el(!vated, 

 and the frontal process apparently more highly developed. 



This is an American type of Rhodoceridi, reaching its highest develop- 

 ment in the United States, where two species occur, one eastern and syn- 

 genic, the other western and antigenic, but several members are scattered 



