Capitophorus essigi Hille Ris Lambers 1953

Capitophorus essigi Hille Ris Lambers

Capitophorus essigi Hille Ris Lambers, 1953:156–157 [type: Tamarack Lake, El Dorado Co., California, 8000 ft. alt., 7–VIII–1947, EOE, on Polygonum alpinum; type-slide with 4 apt.v.f., 3 al.v.f., in DHRL coll.].

Capitophorus hippophaes.—Leonard, 1968:9 [not Walker; determined as C. gilletti Theobald by E.O. Essig; Essig slides seen by Leonard at Cornell University undoubtedly of the same series referred to herein, from University of California, Berkeley].

DIAGNOSIS.—Capitophorus essigi resembles the other species (C. hippophaes) living on Polygonum in having clavate cornicles but differs in having shorter antennae, 4 pairs of rows of setae on abdominal segments 1 to 5, more expanded head setae and greater proportion of cornicles to cauda (2½–3¼ vs. 1¾–2¾). Alates differ further in having less pointed caudal tip. It is similar to C. shepherdiae and C. xanthii in cornicle shape and shortness of antennae but differs in size of body setae in apterae and presence of more sensoria on antennal segment V (7–16 vs. 0–6 and 1–6, respectively) of alatae.

DESCRIPTION.—Apterous Viviparous Female: Body spindle-shaped, pale with tips of rostrum, tibiae and entire tarsi darkened. Tergum slightly sclerotic, imbricate to reticulate, with granular light brown patches from mesothorax to sixth abdominal segment; reticulate-spiculate on posterior segments, spicules blunt, stout. Head with moderately produced meso- and laterofrontal tubercles; mf 1p, lf 1p, vlf 1p, df 4p, vf 2–4p (usually 3), pc 2p, ac 4 arranged 1–2–1, and md 1–1p (usually 3): dorsal setae widely globular at apices, mf, lf, and df–1 distinctly stemmed, slightly longer than rest of df’s; ventral setae except ac similar in shape but less expanded distally. Antennal segment I produced on mesodistal margins, imbricate, with 5–7 knobbed setae aside from basal pointed seta on dorsum; a.s.II with setae, with 1 occasionally added or missing; a.s.III and IV fused in some individuals or asymmetrical in same individual (46.7% of 137 antennae examined with fused III and IV); unguis averaging 3¼ times base of a.s.VI.

Thoracic and abdominal chaetotaxy rather irregular but composite pattern as follows: prothorax with usual 8 setae arranged in 2 transverse rows of 4; meso- and metathorax 2–1–2 on each side; abdominal segments 1–6, 2–1–1–2, but a few setae may be added or missing in any row on either side; abd.s.5 2–1–1, submarginal pair absent; abd.s.6 with partly duplicated spinals; abd.s.7 and 8 with median unpaired seta plus 2 closely associated and a marginal seta on each side of median one on 7, and 5–8 setae in addition to median one on 8. Body setae globular to fan-shaped, sessile; setae from prothorax to abd.s.6 minute, those on abd.s. 7 and 8 about equal to anterior head setae in size. Cauda tapering to acute point; spiculate; with 5–9 setae, 2 or 3 pairs lateral, remainder posterodorsal. Cornicles clavate, slightly dusky on distal ⅓; imbricate; 2½ to 3¼ times as long as cauda. Rostrum IV+V rostrate, with short pointed apex; chaetotaxy as in other Capitophorus species, i.e., ad setae absent, ml and pl setal bases rather close.

Measurements (in mm) of 15 specimens (including 2 types): BL 1.87–2.19 (2.04), We .37–.42 (.396); a.s.III .24–.32 (.279), a.s.IV .20–.25 (.21) or III+IV .39–.55 (.443), a.s.V .16–.23 (.188), a.s.VI .08–.10 (.083) + .23–.31 (.272); cornicles .52–.75 (.643), cauda .20–.23 (.220); hind tibiae .72–1.0 (.92), hind ta–2 .10–.12 (.108), and rostrum IV+V .115–.13 (.121). Length of head setae: mf .0264–.0418 (.0327), If .0154–.0330 (.0259), df–I, .0220–.0418 (.0354), df–2 .0154-.0286 (.0212), ipf .0110–.0198 (.0127), and opf .0132–.0220 (.0168). Proportions of a.s.III:IV:V, 1: .70–.85 (.79): .55–.67 (.69); VIu/VIb 2.80–3.75 (3.27); co/ca 2.52–3.22 (2.91); rostrum IV+V/ hind ta–2 1.0–1.30 (1.12).

Alate Viviparous Female: Head, thorax, spinopleural and marginal abdominal sclerites and antennae dark brown; legs brown with apices darker; anterior wing margin, wing veins, distal two rostral segments, club of cornicles, cauda, subgenital and anal plates lighter brown. Head and antennal segments I and II chaetotaxy as in apterae but setae shorter, less expanded. A.s.III and IV separate; secondary sensoria distributed as follows: 36–55 (46.35 ± 2.45, n = 20) on a.s.III, 16–32 (24.75 ± 2.34, n = 20) on a.s.IV, and 7–16 (10.24 ± 1.19, n = 17) on a.s.V; unguis averaging 3¾ times base of a.s.VI. Abdomen with well-developed, rectangular central abdominal sclerite; spinopleural sclerites of anterior and posterior segments less defined; marginal sclerites well developed; chaetotaxy as in apterae (2–1–1–2), also with irregular submarginal rows; setae short, thick. Cauda constricted about middle, tapering gradually from there to acutely rounded apex; spiculate; with 2 or 3 lateral pairs and 1 posterodorsal setae. Cornicles clavate, imbricate especially cylindrical base; about 3¼ as long as cauda. Rostrum IV+V as in aptera.

Measurements (in mm) of 10 specimens (including 3 types): BL 1.55–2.09 (1.87), We .35–.40 (.37); a.s.III .41–.49 (.433), a.s.IV .24–.32 (.288), a.s.V .22–.27 (.248), a.s.VI .08–.11 (.097) + .35–.42 (.368); cornicles .42–.53 (.51), cauda .14–.17 (.155); hind tibiae 1.02–1.13 (1.08), hind ta–2 .10–.12 (.111) and rostrum IV+V .10–.13 (.118). Length of anterior head setae: mf .0110–.0198 (.0149), and df–1 .0132–.0242 (.0182). Proportions of a.s.III: IV:V, 1: .57–.82 (.66): .49–.67 (.58): VIu/VIb 3.18–4.38 (3.81); co/ca 3.00–3.71 (3.29); rostrum IV+V/ hind ta–2 .92–1.18 (1.07).

Sexuales: Unknown.

HOSTS.—Winter host: unknown. Summer host: Polygonum alpinum.

DISTRIBUTION.—C. essigi has been collected only from high elevations in California. An alate female has been recovered from trap pans in Washington.

SPECIMENS EXAMINED.—Type-slide, with 4 apt.v.f. and 3 al.v.f; 71 apt.v.f. and 75 al.v.f., with same data as types except for elevation (7800–8300 ft.); 3 apt.v.f. and 3 al.v.f. with data as in types but from Upper Echo Lake area; 1 al.v.f., Mary Lake Ridge, Sierra Nevada Mts., elev. 10,000 ft., 29–VII–1937, M. A. Stewart, on unknown host; and 1 al.v.f., Yakima, Washington, 25–V–1955, B. J. Landis, in trap pans. All specimens but types in EOE coll.