Dohrniphora venusta Coquillet

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Frank Moron Jones, Entomological News, Vol xxix

Habitat

Found in Sarracenia flava in Summerville, SC

Distribution (See Map)

• Massachusetts (Coquillet)
• Washington, DC (Chittendon)
• St. Vincent, West Indes (Aldrich)
• Florida (Mrs. Slosson)
• Brownville, Texas (Chittendon)
• Grenada and Trinidad, West Indies (Busck)
• Cabima, Panama (Busck)
• "As far south as Peru , " Brues

Description

Egg—Elongated oval, not quite symmetrical; white, pearly, slightly polished, minutely but not closely punctate, surface dry, non-adherent; size, 0.27 x 0.65mm; scattered singly by the ♀; in this stage (at 70°F) three days.

Larva—last stage—Length 4mm; dorsally flattened; brownish-white, unpolished, the texture roughened with fine sparse hairs which are short and microscopic excepted on the larger pointed processes; on each side the segments bear fleshy pointed processes, progressively larger posteriorly; dorsal area above these processes bears four evenly spaced rows of lower smaller protuberances; the ventral surface bears six rows, still smaller, those of the outer row on each side papillate, of the inner rows low and inconspicuous; the posterior spiracles are in contact medially, ferruginous, in shape resembling short stout flasks, somewhat flattened; the head segment at its base on each side bears a single protuberance which consists of a stout bristly basal portion surmounted by a smoothly-rounded knob; the antennae (?) are minute, fleshy, apparently 2-jointed, and without setae; the head contains two chitinized parts or organs, the largest of which, a thin flat plate, brown in color, its margin rounded and entire and with two minute perforations near its anterior edge, is of almost equal area to the entire segment; beneath this is the cephalopharyngeal skeleton, which has one great hook with a low tooth on its under surface, and two prominent backward-pointing barbs above; when the skeleton is mounted on a slide, the slight pressure of the cover glass causes these barbs and a pointed attachment in front of them to separate from the hook, and they are probably segmented to it; on the ventral surface of the succeeding segment is an 8-toothed labial (?) plate; this, with the cephalopharyngeal skeleton, seems to constitute the only chitinized mouth parts. The larvae are usually so smeared and discolored with moist and putrid food, which clogs and clings to their roughened surface, that their real structure is hidden; about sixteen days are spent in the larval stage.

Puparium—Not greatly different in size and shape from the larva; in color, dull mahogany brown; the pointed processes of the larva, except the lateral row, almost obsolete; on the third day after the hardening of the larval skin and its change of color, two remarkable flat wand-like structures, their edges fringed with rigid cleft filaments, are pushed upward from the dorsal surface of the fourth segment, their points divergent, and become fixed in this position; the larvae seems to possess no such extrusible organs, though two darkened areas on the second segment may indicate their location; these wand-like appendages of the puparium whatever their office, apparently correspond to the thorn-like processes possessed by the puparia of some other species of the Phoridae. About sixteen days are passed in the pupal stage (at approximately 70°F), though at summer temperature the transformations probably occupy less time than is indicated by these records from breedings indoors and under unnatural conditions.

Imago, ♂—Length 2-3mm. Head black, almost opaque; front with the usual fourteen bristles; three strong bristles below the eye on each side; palpi yellow, sparsely black-haired beneath, terminally with three upwardly directed and two downwardly directed bristles; antennae very finely pale pubescent, dark smoky brown above, below slightly paler, more yellowish; arista plumose, black or nearly black; proboscis (in dried examples) reddish –amber, not projecting beyond or below the palpi; oral margin shining brown; no conspicuous ocellar elevations or sutures; eyes finely pubescent.

Dorsum of thorax—dark brownish-black, subshining and thickly set with short stiff backwardly directed black hairs; a strong upwardly directed bristle below the anterior spiracle; a supraalar row of four bristles, the first and last the stronger; four prescutellar bristles, the inner (dorsocentral) pair usually the weaker; scutellum naked, opaque, black, with two strong marginal bristles and a barely distinguishable outer pair; halteres pale dull yellowish-brown.

Legs—with their coxae and most of the pleurae, yellow; fore tibiae always with four, often with five, and sometimes with six, rather weak setae spaced along the outside; middle tibiae spurred, and with a pair of strong setae below the knee, one comparatively weak subapical seta, and on the apical half a series of oblique rows of short, even appressed hairs, from which area also spring stronger hairs; hind tibiae spurred but without other setae, though the hairs are longer and stronger along the outer edge; metatarsi of all legs with rows of short even hairs on the inside, this structure best marked on the posterior metatarsi, each of which bears about twelve such rows; pulvilli present but weak.

Wings—almost hyaline; veins dark brown, the heavy veins nearly black; base of wing bristly and with three long plumose bristles on lower edge; bristles edging the costa; mediastinal vein faintly marked; fourth vein up-curved, reaching margin about equally distant from tip of wing as the fifth; seventh vein weak, but readily distinguishable

Dorsum of abdomen—principally velvety black; the basal segment yellow, more or less black-margined posteriorly; the next segment anteriorly yellow, posteriorly black, with an angular backward projection of the yellow area on the median line; the three succeeding segments black, each with a small yellow triangular marking oh the anterior edge medially; sixth segment broadly yellow anteriorly, posteriorly black; abdomen beneath, pale; hypopygium (left) in fresh examples usually extruded, sometimes folded back beneath the abdomen; the clasp-shaped organs are dark brown, the projecting finger-like organ (which in dried examples may be the only portion visible) yellow or pale amber, with fine black hairs; this organ often bears a solidified globule (indicated by dotted line in figure below of about the same color and texture, which might easily be mistaken for a portion of the insect.

Imago ♀—The larger examples (dried) slightly exceed 3mm in length; colors of head and thorax, and chaetotaxy, practically identical with those of the ♂; the proboscis, in living or freshly killed material is almost twice as long as that of the ♂, is horny, and is usually held vertically as shown in the figure; in dry examples it is drawn up obliquely or horizontally between the palpi, but exceeds them in length by fully its own width; in this sex the second joint of the antenna is usually visible and is yellowish-brown; the abdomen of the ♀ is more dilated and les strongly chitinized than that of the ♂, the longitudinal striations (indicated in the dotted line figure to the right), are more marked, and the velvety black and yellow of the male are replaced by dull smokey brown; terminal joint of the hypopygium (left) pale amber, usually drying to dark brown.

Bibliography

• 1895. Coquillet. The Canadian Entomologist, XXVII, 107. (Phora)
• 1903. Brues. Trans. Am. Ent . Soc., XXIX, 346. (Phora)
• 1903. Brues. " , 349 ( P. dvaricata Ald.)
• 1912. Malloch. Proc. U.S. Nat. Mus ., XLIII, 432.Back to Insect Associates
• 1918. Jones. Entomological News, XXIX, 299, il.