230 



THE AMERICAN ENTOMOLOGIST. 



THE ROYAl HORNED-CATERPILLAR. 



{Ceratocampa, ICitheronia] regalis, Fabr.) 



This insect, which is the subject of our color- 

 ed plate, and which is there illustrated in its 

 three dilFerent stages of larva (a), chrysalis (6) 

 and moth (c), is one of the largest and most 

 beautiful of its order, and its splendor is scarcely 

 equaled by any other North American species. 

 It was originally described in 1793 by Fabricius, 

 under the name of Bornbyx regalis, and was 

 afterwards placed in a new genus (Citheronia) 

 erected by Hiibner. Dr. Harris,* who made it 

 the type of a family (CEEATOCAMPADyi:), and 

 who describes and figures it under the name of 

 Ceratocampa regalis, called it in popular lan- 

 guage the "Eegal Walnut Moth;'' but as it is 

 found in well nigh equal abundance on the 

 Black Walnut, Butternut, and Persimmon, and 

 oftentimes on the Hickories and Sumachs, and 

 as it is much oftener seen in the caterpillar than 

 in the moth state, we prefer that it shall be 

 popularly known by the above translation of its 

 scientific name. 



Harris's engraving of the catei'pillar scarcely 

 gives a just conception of it, and was evidently 

 taken from an alcoholic specimen. Our flgui-e 

 was taken from a living specimen which was 

 found feeding on the leaves of the Persimmon 

 in Union County, in South Illinois, and it mea- 

 sured over five inches when crawling. Full 

 grown specimens were also sent to us last year 

 from Bushberg, Mo., and from Brighton, Ills., 

 and we found one in the neighborhood of St. 

 Louis, Mo ; but the insect is quite scarce even 

 as far south as the above mentioned points, and 

 occurs still more rarely farther North. 



It is single-brooded, and sometimes remains 

 in the ground, in the chrysalis state, fully eleven 

 months of the year. The moths, in the latitude 

 of St. Louis, usually issue during the last half 

 of June, and the cateriDillars are found full- 

 grown from the middle of August to the middle 

 of September. We have never seen the young 

 caterpillars, but in 1828, Dr. Harris found three 

 of the eggs of this fine insect on the Black Wal- 

 nut, speaking of which he says: " They were 

 just hatched at the time and the caterpillars 

 were near to them resting on a leaf. The posi- 

 tion of these young insects was so peculiar as 

 to attract attention, independently of the long 

 branching spines with which the fore part of 

 their body was armed. They were not stretched 

 out in a straight liue, neither were they hunched 

 up like the caterpillars of the Luna and Poly- 



"Inj . Insects, pp . 398-9 . 



phemus moths ; but, when at rest, they bent the 

 fore part of the body sideways, so that the head 

 nearl)"^ touched the middle of the side, and their 

 long horn-like spines were stretched forward, 

 in a slanting direction, over the head. When 

 disturbed, they raised their heads and horns, 

 and shook them from side to side in a menacing 

 manner. These little caterpillars were nearly 

 black ; on each of the rings, except the last 

 two, there were six straight yellow thorns or 

 spines, which were furnished on all sides with 

 little sharp points like short branches. Of these 

 branched spines, two on the top of the first 

 ring, and four on the second and the third rings, 

 or ten in all, wore very much longer than the 

 rest, and were tipped with little knobs, ending 

 in two points ; they were also movable, the 

 insect having the power of dropping them al- 

 most horizontally over the head, and of raising- 

 them up again perpendicularly. On the ele- 

 venth ring there were seven spines, the middle 

 one being long and knobbed like those on the 

 fore part of the body ; on the last ring there 

 were eleven short and branched spines. After 

 casting its skin two or three times, the cater- 

 pillar becomes lighter-colored, and gradually 

 changes to green ; the knobs on tie long spines 

 disaijpear, their little points or branches do not 

 increase in size, and finally these spines become 

 curved, turning backwards at their points, and 

 resemble horns." 



The full grown caterpillar,* with its immense 

 green body and its horn-like spines looks truly 

 formidable, while a peculiar habit which it has of 

 spitefully wriggling from side to side, very un- 



*As no comprehensive description of eitlier the lai-va or 

 chrysalis has been published, and as the horns of the larva 

 are wot quite correctly^ represented in our tigiu'e, we annex 

 the following descriptions which were drawn up from three 

 living specimens. 



X)€Scrvption of full grown larva. — Average length when at 

 rest, 4.90; diameter, 0.60 inch. General color, green with a 

 yellow cast. Smooth and polished. Thoracic segments 

 narrowest, and of a delicate celestial-blue. Segment 

 ) quite small with two tolerably long, straight, serrate, 

 orange-colored horns projeciing from it anteriorly over the 

 head, and six other minute black horns, each with a yellow 

 base: 2, larger, with two polished black spots in front, 

 each constricted in the middle, and with eight serrate 

 horns, four of them small and black and the other four ([uite 

 long, backwardly curving and of an orange-brown or Vene- 

 tian red with black extremities: 3, largest of all, with 

 horns as on 2, and with two ranch larger black patches in 

 front, runningon to posterior portion of 2: 4, o, 6, 7, 8, 9 and 

 10 each of about a size and each with six short black back- 

 wardly slanting, compound or serrated spines, which spring 

 from a somewhat elevated celestial-blue ground, which in 

 some specimens forms a distinct blue transverse ridge : 11, 

 with but five of these spines, the two dorsal ones being sup- 

 planted by one which is central and larger : 12, with seven 

 spines : 4 to 11 inclusive have each a lateral posteriorly and 

 downwardly oblique, cream-colored band, which is abrupt 

 anteriorly and edged above with smoky-black, but which 

 merges gradually into the green posteriorly. Stigmata 

 large, oval and black, with a smoky line rimnmg from each 

 to the lowei' horn Cervical shield small, yellowish-brown 

 and with two cuneiform black spots between the larger 

 horns. Head, caudal plate and anal prolegs outwardly, of 

 the same orange-brown color as large horns; the caudal 

 plate with a minute black wart each side, and the anals each 

 with one at their lower edge. Thoracic legs also of the 



