Macrocheilus Hope, 1838

Zhao, Danyang & Tian, Mingyi, 2012, Taxonomic notes on the Macrocheilus Hope (Coleoptera, Carabidae, Helluonini) from Oriental Region, with description of one new species from the Philippines, ZooKeys 228, pp. 77-100 : 77-78

Genus Macrocheilus Hope, 1838

Macrocheilus Hope 1838: 166. Type species: Macrocheilus bensoni Hope, 1838. Jeannel 1949: 1041. Zhao and Tian 2010:4.

Acanthogenius Reiche 1842: 334. Type species: Helluo impictus Wiedemann, 1823.

Generic diagnosis.

Medium sized (length from 8.0 to 17.0 mm), elongate, whole body coarsely punctuate and pubescent, except for labrum and middle region of ventral side of head. Head with two supraorbital setae on each side; ligula fairly wide, deeply impressed beneath at sides of base; mentum deeply emarginated, with a long and slender tooth; palpi varied in form; labrum extraordinarily or well developed; mandibles dorsally covered by labrum or not covered; antennae stout and flat, densely pubescent from antennomere 5. Pronotum truncate-cordiform or quadrate, basal margin more or less produced backwards in middle; lateral margin with two setae, one just before middle, and the other at hind angle. Elytra with deep striae and setiferous pores; intervals slightly or rather convex, interval 8 usually wide. Metepisterna elongate and very narrow in all species. Tarsomere 4 emarginate. Wings fully developed. No externally visible sexual dimorphic characters present. Median lobe of aedeagus varied in form. Parameres of aedeagus quite similar, elongate, the left one larger than the right one.

Differences with other genera of Helluonini in the Oriental Region.

Macrocheilus spp., with larger body size, simple 4th tarsomeres, and non-securiform labial palpomere are distinctly different from Colfax spp. (smaller body size, securiform labial palpomere) and Creagris spp. (bilobed 4th tarsomere; smaller body size). Functional wings and the occurrence of a long spiniform median tooth of mentum of Macrocheilus distinguish them from Omphra spp. (which are brachypterous and have a short median tooth of the mentum).

Generic range.

Oriental Region (China, Vietnam, Laos, Cambodia, Myanmar, India, Sri Lanka, the Philippines, Malaysia and Indonesia), Palaearctic Region (Pakistan, Syria, Asia Minor), Ethiopian Region (Ethiopia, Tanzania, Uganda, Senegal, Guinea, Guinea-Bissau, Sierra Leone, Togo, Nigeria, Central Africa, Cameroon, Gabon, Congo, Zimbabwe, Angola, South Africa, Madagascar).

Key to species of Oriental Macrocheilus