Notes on Melitera Dentata Grote.
BY VERNON L. KELLOGG.
WITHPLATE VIII.
At the meeting of the Entomological Club of the A. A. A. S., held in August, 1891, at Washington, Dr. Riley called attention to the habits ofMelitera prodenialisWalker. The larvae burrow into and feed upon the fleshy leaves of the prickly pear,Opuntia. Dr. Riley’s specimens came from Florida. Prof. J. B. Smith has recently bred the moth from the prickly pear in New Jersey. His notes were presented at the same meeting of the Club, and the brief references to the interesting notes of Doctors Riley and Smith, made in the Canadian Entomologist (v. xxiii, num. 11, pp. 242 and 256), suggest the presentation of the following notes onMelitera dentataGrote, the western species of this Phycitid genus.
Chancellor F. H. Snow, of this University, while investigating a grasshopper “outbreak” (Dissosteira longipennis) in eastern Colorado in July, 1891, noted the withered and dying condition of many leaves of the common prickly pear cactus (Opuntia missouriensis), and on examining the leaves found in them certain large, naked, bluish larvae. The larvae were imbedded in the fleshy leaves, eating away the soft inner tissue. The hollowed-out spaces were nearly filled with irregularly spherical, yellowish, translucent casts. The attacked leaves were withered and brown without. Prof. Snow took a few leaves and larvae on July 16, near Arriba, Colorado, and brought them to the laboratory.
The larvae were put into breeding-cage on July 18. On July 28 one larva had spun up and pupated in a corner of the cage behind a small porcelain dish. Another had made a cocoon in a broken, empty pupa-case ofEacles imperialis, but died before pupating. On August —— the adults appeared, and have been determined by Prof. J. B. Smith asM. dentata, Grote. As I am aware of no description of the earlier stages of this species, I record the following notes of description:
Egg.About 1-1.2 millimeters in diameter, surface with broad, meridian-like furrows from one pole for about one-third of the distance to the other pole. Color, creamy white.
Larva.Food plant,Opuntia missouriensis, prickly pear cactus, burrowing into the fleshy leaves and eating the soft, succulent, inner tissues. Length, 40 millimeters. Five pairs of prolegs. Color, one specimen, ultramarine blue; skin, semi-transparent and shining anteriorly, dead blue on dorsum; second specimen, buffy with a bluish suffusion, blue between segments, prolegs bluish, and last abdominal segment blue, especially below; skin more opaque than in first specimen. No pronounced markings of skin; spiracles shining black and present on first thoracic and first to tenth abdominal segments. Head flattened, slightly narrower than first thoracic segment, umber. Prothoracic shield well marked, brownish black; anal shield, smoky brownish. Clothing, limited to tubercled hairs sparsely distributed as follows: a subdorsal line of small tubercles, two tubercles to a segment, each tubercle bearing three short, fine hairs; a supra-stigmatic line, one tubercle to each segment, each tubercle bearing three to four fine hairs; a similar infra-stigmatic line; a sub-ventral line of tubercles, bearing usually four fine hairs, the tubercles of the three thoracic segments in this line situated at base of legs outside, and similarly as to the prolegs on the third to sixth abdominal segments. The tubercles in all the lines are faintly smoky. The larva is rather heavy, and rotund in form, tapering toward both head and posterior segment. It moves with a lumbering gait, but rather rapidly.
Chrysalis.Length, 20 millimeters; in cocoon of silk, loosely covered with small dirt-masses. As made in the breeding cage the cocoons were above ground, but concealed under or in available objects.
Adult.The adults obtained from the breeding cage, (there are no others in our collection), are easily distinguished fromprodenialisWlk., by the much stronger dentations of the outer line of the primaries. Prof. Smith kindly sent a specimen ofprodenialistaken at Ocean Grove, New Jersey, for comparison. The row of marginal black spots on the primaries which Hulst (Tran. Am. Ent. Soc., v. xvii, p. 172) mentions as distinctive of dentata is as pronounced in Prof. Smith’s specimen ofprodenialisas in ourdentata. The much lighter color of the primaries, head and thorax in dentata as mentioned by Hulst is characteristic. An interesting feature in the venation of the hind wings in our bred specimens ofdentatais the considerable coalescence of the sub-costal and costal veins. Vein five is wanting, as mentioned by Hulst. In addition, there is further departure from a normal venation, in that vein seven after rising with six from its stem, (Hulst says: “Six short stemmed with seven”), coalesces for a short distance with eight and then runs free to the margin. Behind theforking of seven and six the stem (remnant of sub-costal) unites with the costal, and its basal portion is wholly merged with the forward vein. This partial disappearance of the sub-costal seems to be shared byprodenialisand is probably characteristic of the genus.
Prof. Smith, as recorded in the Canadian Naturalist, v. viii, p. 242, (1891), bred several specimens ofVolucella fasciata, a Syrphid fly, from the same prickly pear leaves in which theMeliteralarvae were living. It is interesting to note that pupariae and later, adults ofVolucella fasciataandCopestylum marginatum, a closely allied Syrphid, were noted in the Opuntia leaves from whichM. dentatawas bred. (See note by Dr. Williston, Entomological News, v. ii, p. 165, 1891).