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Revision of the Genus Melanactes, with a Proposed New Genus (Coleoptera, Elateridae)

1961; University of Notre Dame; Volume: 65; Issue: 2 Linguagem: Inglês

10.2307/2422967

1938-4238

Jean Mario Mathieu,

Forest Insect Ecology and Management

The present revisional work of the genus Melanactes defines the limits of its six species and presents some ideas regarding their relationships. The distribution of this genus is principally in the United States. Three of the species occur throughout the central and eastern part of the country. One species is confined to the central part and an- other to the East Coast. Finally, one species occurs in south Oregon, California, and northern Baja California (Mexico). One species is placed under synonymy and another is transferred to a new genus herein described, the latter species occurring only in the southern part of Ari- zona. A key to species is presented, and redescription of all species are made. Some suggestions concerning the phylogenetic position of the genus Melanactes and the new genus are also given. Melanactes is a small genus of the family Elateridae or click- beetles. Adults of the genus are large, black, shiny beetles found in or near woody areas, frequently resting on the bark of tree trunks. Larvae are very rarely collected, and only the larva of M. densus has been associated with its adult. Since the life cycle, at least of M. densus, is very long, it is unlikely that the larvae of the genus are predaceous. Rather, they probably feed on decomposing woody ma- terial. The genus, endemic to North America, is represented by six species. Previously, eight species were listed but in the present study one of these is assigned to a new genus and another is placed in synonymy. The classification of the species of the genus Melanactes has been in a confused state for a long period of time. As in many genera of Elateridae, its species do not have striking morphological differences; for example, even the male genital organs, which in the majority of beetles provide very useful characters for the separation of species, are essentially uniform throughout the genus. Moreover, no one has previously attempted to study the species critically, using all of the material available in museums and private collections. The results of the present study have permitted me to make im- proved definitions of the species as well as to draw conclusions re- garding their phylogenetic relationships. In particular, good inter- specific differences have been found in the female organs of reproduc- tion. Externally, useful characters include those of the sculpturing