Carabids include all of the terrestrial Adephaga other than trachypachids. This is the largest family of Adephaga, with over 30,000 described species. Among the more well-known members of the family are the genus Carabus (Carabini), bombardier beetles (Brachinini), and tiger beetles (Cicindelitae).
Most carabids are predacious. Most of these are generalist predators, but there are a number of groups that have become specialized (e.g., Peleciini and Promecognathini on millipedes, Cychrini and Licinini on snails). A few clades have larvae that are ectoparasitoids on other arthropods (e.g., Lebiini, Brachinitae, and Peleciini). Others are seed-eaters (e.g., Harpalini).
There are very few derived features that identify carabids. In adults, the metacoxae are narrower than other adephagans, with the metapleuron extending posteriorly to contact the second abdominal sternite. There are also a few minor features in the head structure and musculature of larvae (see Beutel, 1995, for a summary).
While carabid phylogeny has been extensively studied, the convergences and reversals present in morphological traits has lead to a great deal of controversy about many groups. Two of these groups, the tiger beetles (Cicindelitae) and wrinkled bark beetles (Rhysodini) are often considered outside the carabid clade. The phylogeny shown of carabid tribes on this and other pages is a conservative consensus view, in which a large number of "basal" groups give rise to a middle and upper grade of carabids. Within this latter group is a large, relatively uniform clade, the Harpalinae, which includes many of the larger, more common carabids.
There are several enigmatic groups, including Gehringiini and Rhysodini, which may be older lineages groups in or they may be related to groups within the Carabidae Conjunctae. Their placement, along with the resolution of other aspects of carabid phylogeny, awaits further analysis of available morphological and molecular data.
Arnett, R. H. 1968. The Beetles of the United States. Amer. Ent. Inst. 1112 p.
Balduf, W. V. 1935. The Bionomics of Entomophagous Coleoptera. J. S. Swift Co., NY. 220 p.
Jeannel, R. 1949. Traite de Zoologie 9: 771-1077.
Legner, E. F., R. D. Sjogren & L. L. Luna. 1980. Arthropod fauna cohabiting larval breeding sites of Leptoconops foulki Clastrier & Wirth in the Santa Ana River, California. J. Amer. Mosq. Contr. Assoc. 40(1): 46-54.