Tachysphex chiastotrichus Pulawski ex Krombein & Pulawski 1994

Tachysphex chiastotrichus Pulawski

NAME DERIVATION.—Chiastotrichus is derived from two Greek words, chiastos, arranged crosswise, and thrix, trichos, a hair; with reference to the midscutal setal pattern of this species.

DIAGNOSIS.—Tachysphex chiastotrichus can be recognized by its setal pattern combined with tarsal structures: midscutal setae oriented posterolaterad on each side of midline (Figure 109), female tarsi of the obscuripennis type, and venter of male tarsomeres V with subapical cluster of spines. Furthermore, the scutal setae are erect or nearly so in chiastotrichus but appressed or nearly so in xanthoptesimus. The densely punctate mesopleuron is a subsidiary recognition feature (most or all punctures less than one diameter apart).

DESCRIPTION (see also xanthoptesimus, page 50).—Scutal punctures nearly contiguous near margins but about one or two diameters apart on disk. Mesopleural punctures (all or most) less than one diameter apart. Episternal sulcus complete or incomplete. Propodeal dorsum rugose or irregularly ridged longitudinally. Hindcoxal dorsum: inner margin not angulate or minimally angulate basally.

Setal length about one midocellar diameter long on vertex, about 0.4–0.5 × basal mandibular width along hypostomal carina; setae inclined but not appressed on scutum, midscutal setae oriented posterolaterad on each side of midline (Figure 109); suberect on mesopleuron; inclined posterad on propodeal dorsum.

Head, thorax, and legs black, but mandible dark reddish mesally and tarsi dark brown. Tegula light brown, humeral plate varying from light brown to dark brown. Wings yellowish, veins light brown. Terga I–IV silvery fasciate apically, also tergum V in female. Frontal vestiture silvery, with golden tinge in some males.

.—Clypeus: bevel shorter than basomedian area; lip weakly arcuate, shallowly emarginate mesally, with two lateral incisions on each side. Vertex width 1.0 × length. Dorsal length of flagellomere I 2.2 × apical width. Forefemoral venter shiny, with minute punctures that are several to many diameters apart. Forebasitarsus with 8–11 rake spines. Venter of tarsomeres V with basomedian group of spines and few setae on each lateral margin basally. Length 6.0–9.0 mm.

.—Clypeus:lip arcuate, distance between lip corners equal to 0.7 of distance between corner and orbit. Vertex width 1.0–1.1 × length. Dorsal length of flagellomere I 1.6–1.7 × apical width. Forefemoral notch deep, with finely setose bottom. Venter of tarsomeres V with median group of spines. Punctures fine on sternum II basally, moderately large on sternum II apically, and coarse on sterna III–VI. Length 5.5–7.5 mm. Volsella and penis valve as in bengalensis and drymobius (see Figures 126, 127, 133, 134).

Sterna with usual erect bristles and with setae erect or inclined posterad; setae shorter than one midocellar diameter on sternum II, slightly longer than that on IV–VI.

COLLECTING PERIOD.—January through March, 18–19 May, 22–25 October.

HABITAT.—This species occurs most commonly in the Dry Zone at low elevations with average annual rainfall not exceeding 1700 mm, but two specimens are from the Wet Zone near sea level and average annual rainfall of 2400 mm (Figure 110).

GEOGRAPHIC DISTRIBUTION.—Sri Lanka.

RECORDS.—Holotype: , Sri Lanka, Hambantota District, Palatupana, 22–25 Oct 1970, O.S. Flint (USNM).

Paratypes: SRI LANKA: ANURADHAPURA DISTRICT: Padaviya, KVK, PBK, SK, DWB (1, USNM). COLOMBO DISTRICT: Pamunugama, KVK, TW, LW (1, CAS; 2, USNM); Ratmalana, KVK, PBK, PF, NVTAW (1, USNM). HAMBANTOTA DISTRICT: Hambantota, T.B. Fletcher (1, BMNH); Palatupana, Wildlife and Nature Protection Society Bungalow, KVK, PBK, TW, SS, TG (2, CAS, USNM), KVK, PBK, PF, EGD (1, 2, USNM); Yala, Palatupana, KVK, PBK (1, CAS, 2, USNM). MANNAR DISTRICT: Silavathurai, PBK, TW, MJ, GR (2, CAS, USNM), [PBK] (1, NMC); Kondachchi, PBK, TW, MJ, GR (1, USNM). TRINCOMALEE DISTRICT: Trincomalee, China Bay Ridge Bungalow, KVK, TW, SS, LJ, TG (1, USNM).