Hirtodrosophila chagrinensis (Stalker and Spencer)

Grimaldi, David A., 2018, Hirtodrosophila Of North America (Diptera: Drosophilidae), Bulletin of the American Museum of Natural History 2018 (421), pp. 1-1 : 1-

Hirtodrosophila chagrinensis (Stalker and Spencer)

Figures 3 , 15B , 19 , 40

Drosophila chagrinensis Stalker and Spencer, 1939 : 111.

DIAGNOSIS: Based entirely on female: Head and scutum yellow to orange, latter with faint, slightly darker pair of paramedian stripes; wing yellowish; abdominal tergites shiny, with anterior half dark yellow, posterior half black-brown. Eye with sparse, fine setulae. Oviscapt heavily sclerotized, with vertical row of four posterodorsal pegs above a horizontal, flat row of three apical pegs; spermatheca heavily sclerotized, unique among North American species for large size (ca. 15 μm length vs. usually less than 10 μm) and basal half with five well-defined ribs.

DESCRIPTION: Coloration: Head: Frontal vitta golden bronze, matte, finely striate; ocellar triangle shiny, light outside ocellar boundaries, dark brown within; fronto-orbital plate slightly lighter than frontal vitta, shiny; anterior margin of frons dark yellowish. Antenna: pedicel dark yellow, mesal surface infuscate; basal flagellomere dark brown; arista dark brown, tiny basal articles lighter. Face and cheek cream colored, dark yellow at vibrissal angle; oral margin of face not darkened. Clypeus not exposed in the two specimens; palp dark brown; labellum light brown, rest of proboscis lighter. Eye dull, dark red. Thorax: scutum dull orange, shiny but with light pollinosity, with paramedian pair of faint darker stripes; scutellum approximately same color as scutum; pleura slightly darker than scutum, particularly under wing. Wing yellowish; legs and halter light. Abdomen: abdominal tergites shiny, with anterior half dark yellow, posterior half black-brown; sternites and cerci yellowish; oviscapt melanized.

Head: Antenna: Scape concealed under ptilinal suture; pedicel with setulae and two larger setae; basal flagellomere relatively short, apex reaching to oral margin (but face is short), arista with four relatively short dorsal branches, one ventral branch (between d4 and apical fork). Eye egg-shaped in lateral view, with sparse, short, fine interfacetal setulae. Face short, concave; carina barely developed, mostly concealed by antennae; one pair vibrissae, subvibrissal setulae minute; cheek of moderate depth. Frons: Frontal vitta finely striate, margins between it and ocellar triangle and fronto-orbital plate well defined; ocellar triangle large, anterior corner extended to level of proclinates. Fronto-orbital setae: proclinate slightly shorter than posterior reclinate seta; anterior reclinate small, fine, ca. 0.3× size of proclinate; posterior reclinate approximately midway between ipsilateral proclinate and inner vertical setae. Ocellar seta long, tip extended past level of proclinate; postocellar setae relatively long, ca. 0.7× size of ocellar, crossed at tips. Inner vertical setae upright, inclinate, approximately same length as outer vertical setae, which are lateroclinate and pointed slightly posteriad.

Head measurements (N = 2): CD/ED 0.18 (0.16, 0.20), ED/EW 1.18 (1.16, 1.20), FD/FW 1.09 (1.00, 1.19), FL/LFW 0.85 (0.83, 0.87), HW/ HD 1.46 (1.45, 1.48), Ocellar S-index 1.31 (1.30, 1.33), OR1/OR3 0.81 (0.76, 0.86), OR2/OR1 0.39 (0.34, 0.44), VT-index 1.03.

Thorax: Setation: Acrostichal setae in six rows, one acrostichal slightly enlarged just anterior to transverse suture. Anterior dorsocentral ca. 0.7× length of posterior dorsocentral; posterior dorsocentralabout midway between anterior dorsocentral and scutellar margin. Anterior scutellar setae approximately parallel, 0.75× length of posterior scutellar. Postpronotal lobe with 2 setae; 3 notopleural setae (dorsal one largest, posterior one smallest); anterior supraalar ca. 0.35× length of posterior supraalar; anterior postalar ca. 2× length of posterior postalar; two large katepisternal setae, posterior one larger. Legs: Forefemur with ventral row 5 long setae, 2 long lateral setae; no large setae on mid- and hind femora; male foretarsus unknown; midtibia with large ventroapical seta, hind tibia with small, fine preapical dorsal seta.

Thorax and wing measurements: 4-V index 1.49, 5-X index 1.65, C-index 2.39, DC-index 0.60 (0.59, 0.62), hb-index 2.12, S-index 0.56, ThL 1.17 (1.14, 1.21), ThL/WL 0.45, WL/WW 2.67.

Male Terminalia: Male unknown. Female Terminalia: Oviscapt heavily sclerotized, with vertical row of 4 posterodorsal pegs above a horizontal, flat row of 3 apical pegs, row of 5 minute pegs on ventral margin; oviprovector well developed, fully scaled, scales of moderate size. Spermatheca heavily sclerotized, large (ca. 15 μm length vs. usually less than 10 μm), basal half with 5 well-defined ribs, introvert ca. 0.6× length of spermathecal capsule.

TYPE: Holotype, female. “640, N.[orth] Chagrin, O.[hio], 7/22/37, H.D. Stalker. ” In USNM. According to Stalker and Spencer (1939: 112), “taken from fleshy fungus in North Chagrin Reservation, Cleveland, Ohio, July 27, 1937 (H.D. Stalker).” North Chagrin Reservation is approximately 15 mi NE of Cleveland.

OTHER SPECIMEN EXAMINED: USA: Wisconsin: Mellen, VII/17/52, H.L. Carson, 1♀ (dissected, no. 81), in AMNH.

COMMENTS: Only two specimens are known to me, the holotype and the specimen cited above from Wisconsin, both females that were examined for this study. The male remains unknown. In the absence of specimens I am unable to confirm the records of H. chagrinensis from New York and Michigan cited in several papers ( Lacy, 1981; Vilela and Bächli, 2004).

Figures

FIG. 3. Hirtodrosophila chagrinensis (female) A. Habitus, lateral. B. Head, frontal. C. Abdomen, dorsal.

FIG. 15. Wings.

FIG. 19. Hirtodrosophila chagrinensis, C, D female (diss. no. 81). A. Frons, portion. B. Antenna. C. Spermatheca. D. Oviscapt, lateral.

FIG. 40. Hirtodrosophila chagrinensis, holotype female (USNM). A. Habitus, lateral. B. Head, frontal. C. Head, lateral. D. Head and thorax, dorsal. E. Abdomen, dorsal. F.Labels.