Pleotrichophorus packi (Knowlton 1928)

Pleotrichophorus packi (Knowlton)

Macrosiphum packi Knowlton, 1928:169 [types: Elsimore, Fruita, Lehi, and St. John, Utah, on Chrysothamnus nauseosus; deposited in USNM]; 1935b:136.—Knowlton and Smith, 1936c:213.—Knowlton, 1946:6.

Capitophorus packi (Knowlton).—Palmer, 1952:264–265.—Knowlton, 1954:9.

Pleotrichophorus packi (Knowlton).—Hille Ris Lambers, 1953:115; 1969:167.

DIAGNOSIS.—This species can be easily recognized by its dark antennal flagellum and cornicles; its mixture of slender, knobbed anterior (viz, mf, lf and first 2 pairs of df) and more widely expanded or funnel-shaped posterior (posterior df’s) head setae; the more or less uniform, widely expanded, funnel-shaped setal cover on the dorsum of body; long (.86–1.39 mm., m = 1.11, n = 157), slender cornicles that are about 2¼ times (2.27 ± .04, n = 100) as long as cauda; and the presence of usually 3 (2–5, m = 3.32, n = 182) setae on each side of the cauda.

DESCRIPTION.—Fundatrix: Very much like summer vivipara differing only as follows: a.s.II with setae; appendages relatively shorter; a.s.IV and V subequally long, ⅔–¾ a.s.III in length; unguis much shorter, averaging 3 ⅓ times (2.82–4.08, n = 19) as long as base of a.s.VI.

Measurements (in mm) of 5 specimens (Benjamin, Utah, 28–IV–1935, on Chrysothamnus): B.L. 1.94–2.40 (2.17), We .51–.56 (.532); a.s.III .61–.70 (.644), a.s.IV .45–50 (.466), a.s.V .43–.50 (.457), a.s.VI .15–.17 (.160) + .48–.58 (.523); cornicles .68–.77 (.73), cauda .33–.36 (.344); hind tibiae 1.13–1.20 (1.17), hind tax2 .13–.15 (.140), and rostrum IV+V .09–.11 (.101). Proportion of a.s.III: IV:V, 1: .69–.74 (.72): .67–.74 (.71); VIu/VIb 2.82–3.67 (3.28); co/ca 1.92–2.24 (2.13); rostrum IV+V/ hind ta–2 .64–.85 (.72).

Apterous Viviparous Female (summer form): Color in life rather shiny bluish green to apple green (Knowlton, 1928); cleared specimen pale with with tips of rostrum, tibiae, entire tarsi, antennae from near bases of a.s.III, and cornicles from near bases dark brown. Body rather slenderly spindle-shaped, averaging 2.72 (1.87–3.30, n = 86) mm long, .58 (.51–64, n = 91) mm wide across eyes. Head with slightly produced mesofrontal and more developed laterofrontal tubercles; mf 1p, lf 2–4 on each side, vlf 1p, df 14–26 (18.16 ± .56, n = 90), vf 5–11 (usually 8), pc 2p, ac usually 4, and md 3–5 on each plate; dorsal setae of 2 basic shapes: mf, lf, and 2 anterior pairs of df elongate, with apices blunt to slightly knobbed or enlarged but extreme tips pointed, posterior df’s flattened apically or funnel-shaped; ventral setae all elongate, mostly blunt-tipped but vf’s may be slightly knobbed and some of ac and md may be pointed; mf .0352–0572 (.0457, n = 88) and df–1 .0396–.0726 (.0504, n = 101) mm long. Antennal segment I moderately produced mesodistally, almost smooth, with 5–17 (usually 9 or 10), long, blunt to knobbed setae aside from usual pointed one on dorsum. A.s.II faintly imbricate and with blunt or knobbed setae. A.s.III with rather long, knobbed setae, longest about ⅔ basal diameter of segment; with 1–15 (6.02, n = 152) small sensoria. A.s.IV equal to or slightly longer than a.s.III, and a.s.IV about 9/10 a.s.III; unguis 4¼to 7 times (5.68, n = 46) as long as base of a.s.VI.

Tergum smooth on disk, becoming faintly striate-spiculate caudally; body setae moderately dense, funnel- to fan-shaped. Cauda slenderly elongate, very slightly constricted basally, apex acute but rounded; spiculate; with 2–5 (3.3, n = 182) setae on each side, 0–3 (usually 1) setae on posterodorsal surface. Cornicles .86–1.39 (1.11, n = 157) mm long, 2–3 times (2.27 ± .04, n = 100) as long as cauda; slenderly cylindrical, widest at base, narrowing to about ½ basal diameter before becoming slightly thickened on apical 1/10 conspicuously imbricate-spiculate, dark for most of its length. Legs with 3, 3, 3 setae on first tarsal joints. Rostrum IV+V .09–.12 (.104, n = 94) mm long, ½ to ¾ (.65 ± .01, n = 100) as long as hind ta–2; tapering to acute tip but with posterior margin slightly convex; with 1 basal, 2 dorsal and 3 lateral pairs of setae, ml and pl about ⅔ as long as al setae.

Measurements (in mm) of 15 specimens (8 from Bridges National Mon., Utah, 12–VIII–1967 on Chrysothamnus nauseosus; and 7 from Delta, Utah, 10–VI–1968 on Chrysothamnus sp.): B.L. 2.50–3.15 (2.78), We .52–.62 (.57); a.s.III .74–.91 (.806), a.s.IV .72–1.09 (.850), a.s.V .60–.82 (.717), a.s.VI .13–.20 (.161) + .72–1.06 (.881); cornicles .98–1.36 (1.14), cauda .45–.53 (.483); hind tibiae 1.37–1.90 (1.66), hind ta–2 .15–.18 (.163), and rostrum IV+V .09–.115 (.103). Proportions of a.s.III:IV:V, 1: .89–1.37 (1.06): .80–1.03 (.89); VIu/VIb 4.23–7.07 (5.49); co/ca 2.04–3.02 (.235); rostrum IV+V/ hind ta–2 .56–.73 (.64).

Alate Viviparous Female: Cleared specimen with pale faintly sclerotic head; ring around ocelli, basal 2 antennal segments, mesothorax, abdominal sclerites, wing veins, mesodistal surfaces of femora and almost entire tibiae medium brown; tips of rostrum and tibiae, entire cornicles, antennae from near bases of a.s.III and entire tarsi dark brown. Morphologically much like aptera, differing as follows: df setae fewer (12 and 16 in 2 specimens); more sensoria on a.s.III (9–15 according to Palmer, 1952); abdomen with 2 pleural sclerites from segments 1 to 7 (these may be broken into 2 pairs on discal segments), spinopleural thickenings on caudal 2 segments; abdominal setae less expanded and sparser.

Measurements (in mm) of 1 specimen (St. John, Utah, 19–VI–1956, GFK, on C. nauseosus): BL 2.17, We .50; a.s.III .82 and .84, a.s.IV .86 and .88, a.s.V .70 (one side only) and a.s.VI .16 + .95 (one side), cornicles .83 and .88, cauda .43, hind tibiae 1.71 and 1.73, hind ta–2 .16 and .17, rostrum IV+V .10, mf both .0286 and df–1 .0440 and .0462 mm. Number of sensoria on a.s.III 11 and 14; lateral caudal hairs 3 and 4.

Oviparous Female: Similar to viviparous aptera except as follows: posterior df and dorsal abdominal setae longer, less expanded; cauda shorter, stouter, darker; subgenital plate with more numerous, all pointed setae; basal half of tibiae swollen, bearing numerous pseudosensoria.

Measurements (in mm) of 1 specimen (Panguitch, Utah, 5–X–1956, on Chrysothamnus sp.): B.L. 2.30, We .58; a.s.III .83 and .84, a.s.IV .72 and .73, a.s.V .64 and .68, a.s.VI .16 + .75 (one side only); cornicles .89 and .91, cauda .34; hind tibiae 1.39 and 1.43, hind ta–2 both .16, rostrum IV+V .10; mf .0374, and df–1 .0440. Number of sensoria on a.s.III both 4; number of lateral caudal hairs 5 and 4 and of posterodorsal hairs 3; number of df setae 12.

Male: Not known.

HOSTS.—Chrysothamnus nauseosus, C. nauseosus var. graveolens, and C. parryi.

DISTRIBUTION.—Widely distributed in Utah; also recorded from Arizona, Idaho, Nevada and Wyoming near their borders with Utah, and from northern Colorado.

TYPES.—No type-specimens seen and no lectotypes designated from original type series. Cotypes, fundatrices and apt.v.f.’s from Elsimore, Fruita, Salina, and St. John, Utah, at the USNM, CSU and GFK collections.

SPECIMENS EXAMINED.—Numerous apterous viviparous females from the following localities: ARIZONA: Fredonia. IDAHO: Emmett. NEVADA: Contact. UTAH: American Fork, Beaver, Beaver Canyon, Benjamin, Current Creek, Delta, Deseret, Draper, Emery, Fruitland, Glendale, Goshen, Green River, Hinckley, Indian Canyon, Kanab Creek, Kingston, Leamington, Losee, Mt. Carmel, Oasis, Panguitch, Pine Valley, Promontory, Provo Canyon, Santa Clara, Soldier Springs, St. John, Sutherland, Vernal Creek, Vernon, Wolf Creek Canyon and Woodruff. WYOMING: Fort Bridger.