Calisius dilaticeps Usinger 1946, new species
Creators: name: Usinger, Robert L.
Publisher: name: Bernice P. Bishop Museum, Bulletin 189
Year: 1946
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Aradidae
Calisius
Calisius dilaticeps

description: 32. Calisius dilaticeps, new species (fig. 5).
Elongate-oval, subflattened above, with lamellately dilated anterior margins of head and variegated coloration.
Head slightly longer than broad, 24: 21, subflattened and densely, coarsely granulate above, the anteocular region reaching about to apex of third antenna! segment, its sides depressed and distinctly lamellate; antenniferous tubercles short, scarcely attaining apices of first antenna! segments, divergent, blunt at apices; postocular spines small but distinct, bent slightly forward, not reaching as far as lateral margins of eyes. Antennae slightly shorter than widtl1 of head including eyes, 19: 21.S; proportion of segments one to four as 4: 4: 4: 7.
Pronotum three fourths as long as head and about twice as broad across humeri as long, 38: 18; six distinct but small tubercles on disk of anterior lobe and two on posterior lobe; lateral margins with four well-developed denticles on each side, each tooth stout and longer than broad; humeri rounded with ill-defined granular elevations.
Scutellum 2.5 times as long as pronotum, distinctly narrowing to slightly beyond middle, then briefly dilated at apical fifth beyond which it narrows roundly to subflattened apex. Disk strongly triangularly elevated at middle of base with four basal tubercles, a subbasal, obliquely transverse carina laterally on either side, a marginal granular carina and a median longitudinal carina, this last decreasing posteriorly, granular, with two small white granules at apex. Connexivum less than half as broad as scutellum at level of apex of corium, 9: 23, evenly arcuate, distinctly elevated laterally, with a double row of short but distinct, bluntly rounded denticles, 3 pairs to each segment, these denticles about half as long as denticles on antero-lateral margins of pronotum.
Under surface convex and superficially punctured, the thoracic sterna flat and glabrous and impunctate at middle. Ostiolar canal with three prominent, blunt denticles along anterior margin. Eighth abdominal segment large beneath and produced postero-laterally into slender, apically obtuse arms on either side of genital segment. Male genital capsule convex, roundly elevated posteriorly and ventrally along middle and produced upward at middle postero-dorsally. A strongly arched median hood over genital capsule dorsally just behind connexivum proper, this short hood with a subflattened, elongate-oval tubercle on either side.
Color variegated white, ochraceous, and brown, the head white with brown eyes and postocular region laterally except for white postocular spines, the pronotum whitish ochraceous with brown antero-laterally, white anterior-most lateral denticles, and brown discal tubercles on posterior lobe; hind margin white with a brown submarginal carina just in front of scutellar base. Scutellum whitish with brown basal elevation and a brown semilunar marking on either side just beyond this, a sublateral brown spot near middle of disk and irregularly brown apical fourth of disk extending further forward along either side of median carina. Connexivum ochraceous to whitish with first or first and second pair of denticles on each segment brown and entire disk just in front of genital segments brown. Antennae infuscated basally and apically. Legs pale with brown at base and middle of femora, at middle of tibiae and on claws. Under surface of thorax predominantly pale brownish, of abdomen whitish with brown genital segment medially.
Size: male, length 2.5 mm., width (pronotum) 0.95 mm., (connexivum) 1.05 mm.
Holotype male, and one male paratype, Machanao, June 30, 1:>eatenfrom dead leaves of a fallen tree, Usinger.
This species runs to the Australian interveniens Bergroth or the Papuan cognatus Horvath in Horvath's key (Hist.-Nat. Mus. Nat. Hung., Ann. 11: 623, 1913) but differs from these and all other species known to me, except an undescribed species from Rapa, in its lamellately dilated margins of anteocular portion of head. The proportions of antennae, head, pronotum, and scutellum, and the size and arrangement of pronotal and connexival denticles are also distinctive. This is the first Calisius to be described from north or east of Fiji but I have species from Tahiti, Samoa, and Rapa, and others will surely turn up with further collecting. C. pacificus Kirkaldy from Fiji is impossible to place from Kirkaldy's inadequate description, and the head is missing from the type. It differs from dilaticeps in that the spines on the lateral margins of the pronotum are shorter, the scutellum is longer and feebly widened beyond apical third, and the median carina of the scutellum is more distinct.
description: Published as part of Usinger, Robert L., 1946, Hemiptera Heteroptera of Guam, pp. 11-103 in Insects of Guam II, Honolulu, Hawaii :Bernice P. Bishop Museum, Bulletin 189 on pages 37-39, DOI: 10.5281/zenodo.5173934