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The genus Chelobasis
Chelobasis was proposed by Gray (1832) for the new species Ch. bicolor from South America. Weise (1911a) transferred Arescus perplexus Baly 1858, A. laevicollis Waterhouse 1879, and A. aemulus Waterhouse 1881 to Chelobasis. Maulik (1931) described the larva of Ch. bicolor. Maulik (1932) illustrated and discussed the larva of Ch. perplexa. Chelobasis is one of four genera placed in the tribe Arescini Chapuis (Staines 2002). The tribe can be distinguished from all other Cassidinae by the following combination of characters: elytron without costae, elytral punctures little impressed, pronotum with seta in each anterior angle, antennae with 11-antennomeres, antennae not separated by longitudinal keel, pro- and mesocoxae very large. Head: frontal horn truncate at apex; vertex impunctate, depressed between eyes. Antenna: antennomere 1 lengthened into a ventral process which is as long as antennomere 2. Pronotum: quadrate; anterior margin bisinuate, not deeply bilobed; seta present in each anterior angle; punctate laterally and basally. Scutellum: elongate, triangular. Elytron: margined laterally; apices conjointly rounded; with 10 rows of punctures; non-costate; male without apical appendage. Venter: mesocoxae separated by the diameter of a coxa; prosternal process projecting between mesocoxae; pro- and mesotibiae expanded at apex. Male genitalia: aedeagus curved, apex acute; apical orifice nearly as wide as apex of aedeagus. Species of Chelobasis are extremely variable in coloration and markings. There have been subspecies and varieties proposed but these are merely color forms and are herein treated as synonyms under each species. The male and female genitalia were examined and found not to have any taxonomic value. Sexual dimorphism is absent.
Biology (from Strong 1983). Chelobasis bicolor Gray and C. perplexa Baly develop in the rolled leaves of various species of Zingiberales. Eggs are laid on wet, tender tissue of the host plant and hatch in about 20 days. Larvae begin feeding in rolled leaves immediately after hatching. Development is slow, requiring at least eight months until pupation. Larvae require more than one leaf-roll to complete development and move from maturing leaf-rolls to more tender leaf-rolls at night. Larvae are water penny-like, but much larger and more elongate than Cephaloleia Chevrolat, 1837. Adults are polymorphic and long-lived. In marked recapture studies, adult beetles were found up to 18 months after marking. It is assumed that other species in this genus will be found on Zingiberales.