Oxyptilus delawaricus Zeller, 1873

Matthews, Deborah L., 2017, A new species of Oxyptilus Zeller from the southwestern United States (Lepidoptera, Pterophoridae), ZooKeys 698, pp. 75-93 : 84-90

Oxyptilus delawaricus Zeller, 1873 Figs 10-12, 15-16, 17-18, 21, 25-26, 27-28

Oxyptilus delawaricus Zeller, Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien Vol. 23, p. 320, 1873.

Oxyptilus bernardinus f. finitimus Grinnell, Canadian Entomologist, Vol. 19, p. 315, 1908.

Material examined.

More than 284 specimens were examined from various institutions and label data captured. In the interest of brevity, locality data is given in captions for figured specimens and summarized for all other O. delawaricus specimens examined in the distribution map (Fig. 31). In some cases, where only a state was given on labels and no other state records available, a dot was placed in the center of the state. An exception is Kansas where the dot was centrally placed in Eastern Kansas, reflecting the most likely distribution based on the known distribution of Hieracium within the state ( USDA 2017).

Diagnosis.

As in O. eleanerae , the second segment of the labial palpus bears a scale tuft that extends partway alongside the distal segment distinguishing it from related genera. The species is recognized externally by the ochraceous-tawny ground color; the metascutum with three ochraceous-tawny or clay color stripes, as opposed to buff in O. eleanerae (mid-dorsal stripe may be obscure), and flanked by narrow white stripes with the pattern continued on the first abdominal segment; and patterns of the forewing first lobe. Dorsally, the first lobe is traversed by equally narrow white stripes, as opposed to a wider proximal band as in O. eleanerae . The trajectory of the distal white stripe is also at a smaller angle than in O. eleanerae . Ventrally, the forewing apex is ochraceous-tawny or clay colored as opposed to white in O. eleanerae . The midventral white band of the abdomen is narrow in O. delawaricus , about half the width of that in O. eleanerae . Genitalia characters also distinguish the two species including the longer tegumen lobes and constricted base of the valvular lobe in O. delawaricus males, and the bilobed ostial margin and smaller signa in females.

Redescription

(male, female). HEAD (Figs 15, 16) with labial palpi slender, length about 1.5 × eye diameter. Second segment with ventral scale tuft reaching 0.3 × to.0.75 × of distal segment. Palpi white and clay colored, with clay colored lateral stripe. Basal segment mostly white, distal segment dorsally with white tip. Frons and vertex ochraceous-tawny or clay colored with transverse single row of white scales anterad of antennae and cluster of white scales laterally at anterior margin or across entire frontal margin. Eye bordered by white scales as in O. eleanerae except sometimes with clay colored scales mixed in. Occipital fringe scales mostly bifid, ochraceous-tawny with some white scales mid-dorsally. Antenna with scape and pedicel with three alternating white and brown stripes, anterior stripes chestnut-brown; posterior stripe ochraceous-tawny; flagellum dotted with alternating chestnut-brown and white scales dorsally, drab and minutely ciliate ventrally. THORAX with anterior part of tegulae and mesoscutum russet or ochraceous-tawny, grading posteriorly to clay, cream, and white; mesoscutellum mostly cream colored and white; metascutum with three ochraceous-tawny or clay colored stripes flanked by white stripes. Foreleg (Fig. 11), chestnut-brown and white striped, except coxa proximally white, distally ochraceous-tawny; femur evenly striped, tibia chestnut-brown dorsally, white ventrally; first tarsomeres with dorsal dusky-brown stripe, ventrally white, second and third tarsomere white and dusky-brown banded, fourth and fifth tarsomere solid dusky-brown. Mid and hindleg coxa ochraceous-tawny and white or cream striped; femur white and chestnut-brown striped; tibia white with chestnut-brown bands terminating in scale tufts at spurs. Spurs nearly equal, white dorsally with dusky-brown apex, dusky-brown to black ventrally. Tarsomeres white and dusky brown banded, somewhat variable, with distal tarsomere usually dusky-brown. FOREWING (Figs 10, 11) length, males xˉ = 9.58 mm ± 0.56 (n = 25), females, xˉ = 8.71 mm ± 0.80 (n = 6). Cleft origin 0.48 –0.53× wing length from base, lobe apices acute, second lobe with concave termen. Dorsal ground color ochraceous-tawny. Costal margin dotted with white and chestnut-brown. Discal cell with small central chestnut-brown spot with distal trail of white scales. Area between veins 1A and 2A with diffuse elongate patch of russet and chestnut-brown scales. Cleft base with white spot with smaller chestnut-brown spot posterad. First lobe transected in thirds by two oblique narrow white bands of similar width; basal band projecting at more obtuse angle from long axis of wing than distal band. White scaling of bands extending to costa, with some ochraceous-tawny scales mixed in at margin. Forewing apex ochraceous-tawny, between white bands russet, area just basad of basal white band, russet, gradually grading basally to ochraceous-tawny. In some cases, forewing ground color appearing entirely russet with area between white bands not distinctly darker than apex. Second lobe similarly patterned to first except basal white band diffuse and area just basad ochraceous-tawny. Cleft margins of both lobes with scattered spatulate chestnut-brown scales, and elongate clay colored scales overlapping drab linear fringe scales; white spatulate scales likewise overlapping fringe at white bands. Forewing anal margin with terminal and subterminal groups of drab linear fringe scales as in O. eleanerae , the subterminal patch larger, flanked by white patches of linear scales, and with dense row of shorter overlapping russet and ochraceous-tawny scales. Fringes at basal third of second lobe with small patch of chestnut-brown and white. Fringes of anal margin basad of cleft mixed drab and white with patch of overlapping elongate white scales basad of cleft. Ventral forewing russet basad of cleft, with mixed ochraceous-tawny, clay, and white scales closer to wing base and trailing along narrow chestnut-brown costal margin. Russet scales grading into lobes to ochraceous-tawny, including lobe apices. White oblique bands as on dorsum except wider and with basal band of second lobe absent. Costal margin of first lobe with short conspicuous dusky-brown or chestnut-brown fringe, contrasting white fringe at basal band and apical third of lobe. Fringes of cleft margin mostly drab. Anal margin fringe alternating white and drab as on dorsum but with spatulate scales mostly hidden by linear fringe scales. HINDWING (Figs 10, 11) first and second lobes dorsally russet, basally grading to drab. Fringes drab, sometimes with trace of white two-thirds from wing base along second lobe anal margin. Third lobe ochraceous-tawny on basal two-thirds, russet on distal third adjacent to scale tooth, occasionally uniformly russet. Scale tooth at distal third of lobe with short spatulate russet and fuscous-black scales extending into fringes along anterior margin; anal margin with russet and fuscous-black in distal third forming triangular patch with basal scales longest. Anal margin also with small apical patch of 2-5 fuscous-black spatulate scales in fringes at apex; fringes drab, mixed with white elongate scales and a few fuscous-black scales basad of scale tooth. Ventrally with basal half of first lobe ochraceous-tawny, banded distally by white, russet, white, and ochraceous-tawny respectively; fringes drab or drab mixed with clay or cream color. Second lobe dull russet; venous scales russet or antique brown; fringes drab. Third lobe ochraceous-tawny or russet, with solid white just basad of scale tooth or mixed white and ochraceous-tawny and trail of white bordering anal margin; fringes as on dorsum. ABDOMEN dorsum mixed ochraceous-tawny and clay with varying amounts of chestnut-brown. A white diverging longitudinal subdorsal band present on A1, on posterior half of A2, reduced to patch of white scales on posterior margin of A3-A7. Segments A2-A7 also with small marginal patches of white scales laterally. Males with distinct, mostly pale chestnut-brown, scale tuft laterally on A8, female with banding contiguous from A7. Abdomen venter clay colored, with narrow white mesal band flanked posteriorly by white scale patches. Males with clay colored and white lateral tuft at A8.

Male genitalia (Figs 17, 18) (n=5). Uncus mesally articulated with tegumen, length less than half that of tegumen, bilobed, weakly sclerotized except for lobes which bear short setae. Tegumen bilobed; lobes distinctly longer than valvular lobes, with widened base, slightly concave medial margin, and distally truncate. Valvae symmetrical, with terminal membranous valvular lobe accounting for about one-third of valve length. Valvular lobe bearing deciduous scale tuft and short setae, basal connection constricted and inserted just anterad of apex of main part of valve. Sacculus mostly parallel to valve margin, not distinctly wider at base. Juxta a short curved sclerotized fulcrum attached to membranous sheath of phallobase. Phallus slightly curved; length similar to valve length. Phallobase width similar or just exceeding valve width. Aedeagus slightly longer than phallobase, with subapical spinous crest-shaped process. Vesica tubular, without cornuti. Inception of bulbus ejaculatorius at 0.5 × length of phallobase. Sternite VIII produced as bilobed structure medially supported by saccus, overall length about one-half that of tegumen, notch between lobes reaching about 0.7 × distance to base. Lobes not distinctly widened basally as in O. eleanerae .

Female genitalia (Figs 21, 25, 26) (n=5). Apophyses posteriores about 3.5 × length of papillae anales, moderately sclerotized. Apophyses anteriores absent. Sternite VII overriding VIII but not extending beyond ostium and forming separate recessed pocket on each side of antrum. Ostium formed from margin of dorsal and ventral antrum plates; dorsal (outer) plate projecting as single rounded medially convex rim; ventral plate weakly bilobed or medially emarginate. Antrum length similar to width, generally appearing funnel-shaped with outer collar where fused with sternite VII. Ductus bursae and corpus bursae similar in length. Width of ductus bursae about 0.2 × ostium diameter. Ductus seminalis similar in width to that of ductus bursae; inception point with corpus bursae directly adjacent to that of ductus bursae. Corpus bursae ovoid, with paired, small, serrated blade-like signa, length about 0.6 × ostium diameter.

Larval hostplants and habits.

Larvae web together leaves and feed within these masses on the developing inflorescences of Hieracium (hawkweeds) ( Asteraceae ). Three species have been recorded as hostplants: H. abiflorium Hook., H. cynoglossoides Arv.-Touv. (= H. albertinum Farr), and H. scouleri Hook. ( Clarke 1934, Dyar 1904, Landry 1987, McDunnough 1927).

Distribution and phenology.

Oxyptilus delawaricus occurs in both the western and eastern United States and Canada with a large gap in the distribution representing the Great Plains (Fig. 31). Collection records are concentrated in the Northern and Middle Rocky Mountains and Pacific Northwest, extending south along the Pacific Border into Southern California, and north into the middle of British Columbia. Populations may follow the hostplant range further north and across the northern Interior Plains and Canadian Shield, joined by those known from the Appalachian Highlands and southern Interior Plains. Additional study of material from northern Alberta and Saskatchewan is necessary to determine the northern limits and potential for east-west gene flow within the species.

Distribution records of O. delawaricus do not overlap with those of O. eleanerae which is restricted to sky islands within the southern part of the Intermountain Basin and Plateau Region. No records of O. delawaricus have been found as yet for Colorado, likewise showing a separation of the two species by the Wyoming Basin and Southern Rocky Mountains. Adults have been collected from the middle of May through the first week of September. The earliest confirmed spring records (mid May) are from Northern Mississippi, and are also the southernmost records with dates included on the labels. Late season records (August, September) are from more northern latitudes but no clear flight patterns are evident.

Notes.

Zeller (1873) described O. delawaricus from a male collected along the Delaware River. Barnes and Lindsey (1921) indicate the holotype should be in the British Museum (Natural History Museum, London). Grinnell (1908) described Oxyptilus bernardinus and O. bernardinus form finitimus. Form finitimus was named based on one specimen that differed in the white forewing markings from the rest of the series. Barnes and Lindsey (1921) synonymized Oxyptilus bernardinus with Capperia ningoris (Walsingham) and bernardinus form finitimus with O. delawaricus . Barnes and Lindsey (1921) selected and designated a [lecto]type from five of Grinnell’s specimens which is currently in the USNM type collection. They also found an unlabeled specimen with Grinnell’s bernardinus series which they recognized as the specimen Grinnell referred to as form finitimus and labelled this specimen “type”. The later specimen, however, has not been found in USNM holdings. Male valvular lobes are easily broken off during dissection and frequently missing on older specimens.