Alysson ruficollis Cameron 1898

Alysson ruficollis Cameron

Alyson [sic!] ruficolle Cameron, 1898:25, 26 [“”=; Kandy, Ceylon; type in Hope Entomological Collections, Oxford University].

Alysson ruficollis Cameron.—Bohart and Menke, 1976:458 [listed].

Cameron described A. ruficollis from a supposed male collected in Kandy by Yerbury. The type is a headless female in the Rothney Collection, Hope Entomological Collections, Oxford University. The only label it bears is in Cameron's handwriting, “Alyson/ruficolle/Cam. Type/Ceylon.” Except for the missing head it agrees well with the original description in all but a few minor details. Sexual dimorphism is readily apparent in Alysson, so I suspect that Cameron miswrote “” in the description when he meant female.

The female of A. ruficollis is quite distinct in the Ceylonese fauna in having red markings on the anterior part of the thorax as follows: pronotum except anteriorly in the middle, scutum, scutellum, metanotum, and upper half of meso- and metapleura. The female of Analysson rufescens, new genus and species, also has the thorax partly red, but it is the posterior section as follows: scutellum, metanotum and metapleuron, and propodeum. The male of Analysson rufescens and the putative male of Alysson ruficollis have no red on the thorax. So far as known this kind of sexual dimorphism in thoracic coloration occurs in all species of Alysson in which the female has the thorax partly or entirely red, e.g., the North American A. melleus Say and a presumed new species from Assam. I know of no Alysson males with the thorax partly or entirely red, and Analysson rufescens is the only known species in that genus.

Both sexes of A. ruficollis are readily distinguished from the other Ceylonese species of Alysson by the larger, less numerous areolets beside the transverse dorsal carina of the propodeum (Figure 3). The female has the anterior part of the thorax red and the forewing without an infumated spot, in contrast to A. triangularis, new species, in which the thorax is not partly red and the forewing has a transverse infumated band at the outer third. The front and vertex of the female head were said to be “thickly covered with black hair,” a feature not found in any other Alysson.

The association of sexes is based on the similarly sculptured dorsal and posterior propodeal surfaces. Each sex is known from a single specimen, the female from Kandy, a locality in which I have collected only A. triangularis, new species, the male from Angunakolapelessa. The former locality is in the Wet Zone, the latter in the Dry Zone. The only known male of A. ruficollis was taken along a dry sandy stream bed. I suspect that Yerbury collected the only known female of this species in a sandy area along the Mahaweli River at Kandy. Most of my collecting in Kandy was done in the heavily forested Udawattakele Sanctuary. I collected along the Mahaweli River only once, at Peradeniya a few miles from Kandy.

FEMALE.—Type without head 4 mm long, so original length about 4.5 mm (Cameron said about 5 mm). Head said to be black, the following yellow [more likely creamy]: mandible except apex, palpi, labrum, clypeus, line along inner eye margin from near top, and antennal flagellum beneath; thorax and abdomen mostly black, the following red: pronotum except anteriorly in middle, scutum, scutellum, metanotum, and upper half of meso- and metapleura; the following creamy not yellow: apices of coxae, foretrochanter beneath, hind femur beneath at extreme base, anterior margin of foretibia, basal third of hind tibia, foretarsi, and pair of round lateral spots at middle third of second abdominal tergum; wings clear, stigma and veins brown. Vestiture of head said to be dense and black on front and vertex, clypeus and mandible with much longer white hair; elsewhere vestiture sparse and silvery.

Front and vertex said to be closely punctured; other characters of head are of coloration and vestiture as given above.

Pronotum dorsally with close small punctures, posteriorly with a narrow, deep, feebly crenulate groove except in middle, laterally with close small punctures anteriorly and a few close longitudinal carinae posteriorly above; scutum with small subcontiguous punctures; scutellum and metanotum with smaller, more dispersed punctures; mesopleuron with tiny sparse punctures; metapleuron smooth; dorsal and posterior propodeal surfaces with sculpture similar to that of male (cf. Figure 3) except lateral rugae within propodeal enclosure transverse rather than oblique.

Abdominal punctation and vestiture normal for Alysson; terga I–II impunctate except for sparse, scattered long setae on sides; terga III–IV (V retracted, not visible) with somewhat denser setae on basal half, apical half impunctate.

MALE.—Length 4.4 mm. Black, the following creamy: palpi, basal half of mandible, apical half of clypeus, narrow stripe along lower inner eye margin extending halfway to anterior ocellus, scape beneath, pair of tiny spots on pronotal disk, forecoxa beneath at apex, foretrochanter beneath, basal third of hind tibia, and a pair of small round lateral spots near anterior third of second abdominal tergum; the following light red: apex of mandible, basal five segments of flagellum beneath, rest of forecoxa, midcoxa, inner margin of hind coxa, foretrochanter above, mid- and hind trochanters, rest of legs except the femora, tibiae, mid- and hind tarsi brownish above. Forewing clear except a small slight infumation adjacent to stigma.

Head width 2.5 times interocular distance at antennal insertions and 1.8 times that at anterior ocellus; flagellum beneath without a row of stout, longer erect setae, intermediate segments 1.1 times as long as wide, apical segment not enlarged and wider than penultimate; front with subcontiguous small punctures becoming a little sparser toward ocelli.

Pronotum with a narrow, weakly crenulate groove posteriorly, it and scutum with small punctures separated by about half the diameter of a puncture; side of pronotum with a few longitudinal carinae on upper half, elsewhere with scattered fine punctures; scutellum with a deep, coarsely crenulate anterior groove, elsewhere with scattered fine punctures; mesopleuron with well-developed scrobal sulcus and scattered fine punctures; metapleuron impunctate; dorsal and posterior surfaces of propodeum (Figure 3), areolets on either side of posterior transverse carina larger and fewer in number than in A. triangularis (Figure 5); lateral propodeal surface with fine sparse punctures on posterior half.

Abdominal punctation and vestiture as in female; genitalia very similar to those of A. triangularis.

SPECIMENS EXAMINED.—CENTRAL PROVINCE, Kandy District: 1, no locality label but stated to be Kandy in description (Oxford, the type).

UVA PROVINCE, Monaragala District: 1, Angunakolapelessa, 100 m, 21–23 Jan, K.V. Krombein et al. [collected along dry sandy stream bed] (USNM).