Pleotrichophorus gnaphalodes (Palmer & M. A. 1938)

Pleotrichophorus gnaphalodes (Palmer)

Capitophorus gnaphalodes Palmer, 1938:356 [type: apt.v.f., Estes Park, Colorado, 2400 m elev., 23–VIII–1921, MAP, on Artemisia gnaphalodes1; USNM 52350].

Pleotrichophorus gnaphalodes (Palmer).—Hille Ris Lambers,1966:605; 1969:169.

Pleotrichophorus gnaphalodes (Palmer) [misidentifications].—Robinson and Bradley, 1965:44; 1968:64 [specimens loaned from AGR and collected on Artemisia ludoviciana from Manitoba seen and determined to be P. pseudoglandulosus (Palmer)].

Capitophorus glandulosus (Kaltenbach).—Knowlton and Smith, 1936b:231 [misidentification, in part; collection recorded from Pingree Park, Colorado, on A. ludoviciana seen and determined to be P. gnaphalodes].

DIAGNOSIS.—This species can be recognized by a combination of subequally long cornicles and cauda (co/ca mean ratio of 1.17 ± .03, n = 125), stoutly elongate and constricted cauda and long (.13–.16 mm, m = .143, n = 74) needle-tipped last rostral segment. It resembles P. parilis in general body features but the shape and length of rostrum IV+V is distinctive (.09–.11 mm, m= .099, n = 50 in P. parilis).

DESCRIPTION.—Apterous Viviparous Female: Color in life pale green (Palmer, 1938); cleared specimen pale with tips of rostrum and tibiae, entire tarsi, antennae from apices of a.s.V darker, sometimes also dusky from apices of a.s.III (e.g., specimens on A. douglasiana from California). Body length 1.41–2.18 (1.83, n = 70), width across eyes .40–.49 (.447, n = 72)mm. Head with rather well-developed laterofrontal tubercles, mesofrontal tubercle also prominent; mf 1 or 2p, lf 2–3 on each side, vlf 1p, df 19–36 (27.76 ± .87, n = 71), vf 6–14 (usually 8), pc 2p, ac 4 and md 2–3 (usually 3) on each plate; dorsal setae funnel-shaped, mostly distinctly petiolate, distal half widely expanded; ventral setae also with expanded apices except ac and some md which may be merely blunt; mf .0154–.0528 (.0365, n = 197) and df–1 .0330–.0506 (.0408, n = 134) mm long. Antennal segment I conspicuously produced on mesodistal margin; faintly imbricate, with 4–9 (usually 7 or 8) small, blunt or knobbed setae in addition to usual pointed one on dorsum. A.s.II with knobbed setae. A.s.III faintly imbricate, with small knobbed setae, longest less than ½ basal diameter of segment, bearing 1–4 (2.58, n = 111) sensoria, a.s.IV slightly longer than a.s.V, IV about 9/10, V ¾ length of a.s.III; a.s.VI with unguis 5½ to 7 times (6.27, n = 33) base (slightly shorter in collections made 1–25 March from Berkeley, California, with range of 4.77–7.15 times, m = 5.88, n = 57).

Dorsal body integument smooth to faintly striate on disk, becoming more distinctly imbricate-spiculate caudally from about abd.s. 5; with moderately dense cover of funnel- to cone-shaped setae, without distinct stems. Cauda .20–.29 (.251, n = 73) mm long; stoutly elongate, constricted on basal ¼ or ⅓, apex broadly rounded; spiculate; with 2 pairs lateral and 1 posterodorsal setae. Cornicles .20–.43 (.288, n = 144) mm long and .83–1.56 times (1.17 ± .03, n = 125) as long as cauda; cylindrical, almost uniform in diameter throughout length, apices sometimes dusky; imbricate-spiculate, with spicules rather small, blunt. Legs with 3, 3, 3 hairs on first tarsal joints. Rostrum IV+V slender, apical ⅓ cylindrical, sometimes appearing constricted off as a distinct segment; .13–.16 (.143, n = 74) mm long and 1.00–1.45 (1.15 ± .02, n = 100) times as long as hind ta–2; with 1 basal, 2 dorsal and 3 lateral pairs of setae, ml and pi about ⅓ al setae in size.

Measurements (in mm) of holotype: BL 1.66, We .43; a.s.III .58 and .56, a.s.IV .47 and .46, a.s.V both .39, a.s.VI .15 + .98 and .15 + .97; cornicles both .32, cauda .23; hind tibiae 1.16 and 1.14, hind ta–2 both .12 and rostrum IV+V .14.

Alate Viviparous Female: Head and thorax brown, sclerotic; antennae dark brown; legs dusky to brown with slightly paler femoral bases, darker tibial apices and entire tarsi; abdomen pale, membranous, with dusky or light brown sclerites; cornicles, anal plate and cauda also dusky; anterior wing margins dusky, wing veins slightly darker brown; apical 2 rostral segments brown, sclerotic. Morphologically much like viviparous aptera, differing in presence of fewer df setae (10–19, m = 14.96, n = 28); presence of more sensoria on a.s.III (6–19, m = 13.9, n = 46); presence on abdomen of 2 indistinct spinal dashes, 2 pairs of pleural and 1 pair of marginal sclerites; abdominal setae sparser, relatively longer; cornicles (.15–.23, m = .198, n = 55), cauda (.20–.25, m =.216, n = 28) relatively shorter, co/ca ratio slightly smaller (.75–1.32, m = .91, n = 55).

Measurements (in mm) of 10 specimens on Artemisia douglasiana: BL 1.65–1.90 (1.78), We .39–.43 (.415); a.s.III .50–.62 (.588), a.s.IV .46–.58 (.508), a.s.V .40–.50 (.449), a.s.VI .13–.16 (.149) + .85–.99 (.926); cornicles .15–.23 (.202); cauda .20–.23 (.217); hind tibiae 1.12–1.27 (1.21), hind ta–2 .12–.14 (.131), rostrum IV+V .12–.14 (.134); mf .0220–.0374 (.0307) and df–1 .0330–.0418 (.0373). Proportions of a.s.III:IV:V, 1: .81–.94 (.86): .69–.81 (.76); Vll/VIb 5.31–6.53 (6.09); co/ca .71–1.32 (.93); rostrum IV+V/ hind ta–2 .92–1.17 (1.04). Sexuales: Unknown.

HOSTS.—Artemisia douglasiana (= Artemisia vulgaris var. heterophylla) and Artemisia ludoviciana (= A. gnaphalodes).

DISTRIBUTION.—Rather widely distributed, with records in the states of California, Colorado, Kansas, and Oklahoma.

SPECIMENS EXAMINED.—Holotype; paratypes from Colorado State University collections: 3 apt.v.f., 1–VII–1898, La Porte, Colorado, CPG, on Artemisia ludoviciana, and 11 apt.v.f., 21–III–1935, Pingree Park, Colorado, GFK on A. gnaphalodes. Other specimens from CALIFORNIA (all on A. vulgaris var. heterophylla and in EOE coll.): Berkeley, collected by EOE on 12–III–1935 (12 apt.v.f. and 9 al.v.f.) and 25–III–1935 (19 apt.v.f. and 20 al.v.f.), and by J.H. Mitchell on 1–III–1938 (11 apt.v.f. and 1 al.v.f.); Lattonda Grade, 2 apt.v.f., 30–XI–1933 by P.J.B. COLORADO: Pingree Park, 20 apt.v.f., 21–VIII–1935, GFK on A. ludoviciana (GFK coll.). KANSAS: Manhattan, 1 al.v.f., 22–IV–1965, Project NC–67, at U. Wise., by suction trap (U.Minn, coll.). OKLAHOMA: Cherokee, 1 al.v.f., 20–IV–1964, Project NC–67, U. Wisc., by suction trap (U.Minn, coll.).