The feeding apparatus of 17 species of ground beetles (Carabidae), representing 17 genera and 12 tribes has been studied, and the observations correlated with gut content analyses and the ability of certain species to regurgitate pre‐oral digestive fluids. The diverse feeding habits of species investigated include zoophagous fluid feeders, zoophagous fragmentary feeders and mixed feeders. In the last‐named group, the food intake may be both fluid and fragmentary, and either of animal or of both animal and plant origin.

The structure of the mouthparts and foregut of some caraboid beetles has been correlated with their type of feeding mechanism. These may be adapted to fragmentary feeding, fluid feeding (where pre‐oral digestion is important), or to mixed feeding (a large category which ranges from a mainly fluid to a mainly solid intake). Head structures concerned with feeding have been discussed in relation to these methods; they include the mandibles, maxillae, labrum‐epipharynx and anterior foregut, proventriculus, labium‐hypopharynx and the head floor. Different types of head floor were denned in relation to gular structure, in particular the presence or absence of the mid‐gular apodeme. Convergent evolution of feeding mechanisms was noted amongst both fragmentary feeders and fluid feeders; in the latter group, sucking pumps have been evolved in the Carabitae, Scarites, Cicindelidae, Paussini and some other caraboids. It was suggested that head shape in caraboids may reflect locomotory adaptations more frequently than feeding adaptations.

With 12 figures in the text)Variations in height of prothorax and hind body; hind body, prothorax, labrum, clypeus and metatergum widths; metasternum, metatergum and wing lengths; eye protuberance and width of antennal insertions are discussed and compared with body lengths in different species of carabid beetles. These various parameters have been displayed in the form of tables, ratios and graphs; they have also been discussed in relation to the various habits (i.e. feeding, locomotory, burrowing, flying) of the different carabid beetles; certain trends were noted.The Carabini were found to be generally heavier and greater in volume (i.e. bulkier) than other carabid beetles, and this is reflected mainly in the size of the hind body, notably hind body depth. The Carabini are also much stronger than other Carabinae group I species. The explanation for this probably lies in the nature of the leg muscles and their coxal insertions. This is reflected in the prothorax which is significantly deeper and may reflect the size of the contained extrinsic procoxal muscles. It was suggested that the size, bulk and strength of the Carabini may help them overcome the 'environmental resistance' of their various habitats.Ground beetles which live in restricting or confining habitats, such as in fissures in the ground, have a tendency to be narrower in width and shallower in depth, with a prothorax similar in width to the hind body. It was suggested that this type of body form would minimize friction by causing less obstruction when moving through confined spaces.Visually hunting carabid beetles (spp. of Cicindela, Elaphrus, Notiophilus and Asaphidion) have large eyes which protrude significantly more than those of species which hunt using other senses (i.e. tactile and olfactory). The prothorax of these species (apart from Notiophilus) is also significantly narrower than the hind body. It was suggested that the combination of these two features increases the area of the visual field and enhances their hunting abilities. Additionally, a narrow prothorax may allow the elytra to open quickly, and swing forwards without hinderance from prothoracic margins; this is essential in a beetle that hunts in the open where the ability to escape rapidly by flying greatly reduces the possibility of predation. In Notiophilus, however, the prothorax is similar in width to that of the majority of other ground beetles. This structural difference is probably correlated with its special feeding habits, its particular hunting strategy and its habitats.In Cicindela, the feeding apparatus is modified to form a unique fluid-feeding mechanism. Considerable secondary morphological changes have modified the head structure. In particular, the labrum and clypeus have expanded laterally and the positions of the eyes and antennal insertions have shifted dorsally.In some ground beetles, atrophy of the wings and their associated muscles has resulted in changes to the meso-and metathorax. This is reflected in a decrease in the sizes of the metatergum and met-epis...

Recordings of maximum running speeds and maximum horizontal pulling (= pushing) forces have been obtained for 72 species of cursorial and fossorial ground beetles (Carabidae: Coleoptera) belonging to 19 tribes and 12 supertribes. Fore leg, pro‐ and meso‐femoral and tibial and mid leg measurements have also been made and all these parameters have been correlated with body lengths. It was found that those species (mainly Carabinae group I, i.e. Nebriini, Notiophilini, Loricerini, Elaphrini, Cicindelini) with relatively long, slender pro‐and mesofemora, long pro ‐ and mesotibiae and small meso‐coxal articulations were faster runners (i.e. sprinters) but weaker horizontal pushers. In contrast, species (mainly Carabinae group II, i.e. Broscini, Trechini, Pogonini, Bembidiini, Patrobini, Pterostichini, Zabrini, Callistini, Oodini, Licinini, Harpalini) with relatively short, broad pro‐femora, short (slender) mesofemora, short pro– and mesotibiae, and larger meso‐coxal articulations were stronger horizontal pushers but were slower runners. Carabinae group III (Scaritini), however, which have very short, narrow pro‐ and mesofemora, very short pro‐ and mesotibiae, and large meso‐coxal articulations were found to be very strong horizontal pushers but very slow (relatively) runners. The Carabini (including Cychrini), however, resemble Carabinae group II in their running and pushing abilities although their legs are structurally similar to those of Carabinae group I (i.e. relatively long and slender with small meso–coxal articulations). In fact, species of Carabini are fast walkers, their prey is generally slow moving (i.e. slugs, snails and caterpillars) and they hunt in restrictive habitats such as weed patches, meadows or woodland grass which produce a considerable amount of environmental resistance. Most Carabini have a heavy, powerful body which seems to be well adapted to overcoming this resistance.

This paper attempts to describe the relationship between habit, body structure and form in five species of ground beetle representing five different tribes. The results support and broaden the basis for currently accepted ideas about the mode of life of Scaritini, Morionini, Licinini, Omophronini and Galeritini. It examines feeding mechanisms, leg structure and body form. In this study two types of feeding method are recognized: fluid or semi‐fluid feeding, as in Scarites subterraneus, and mixed intake feeding. In the second method, food ingested varies from fluid, mush and recognizable arthropod fragments (Morion monilicornis and Omophron labiatum) to mainly fluids or semi‐fluids with some fragments (Diplochila major and Galerita lecontet). All these species show morphological adaptations of their feeding mechanisms indicative of their feeding habits. Pro‐, meso‐ and meta‐femoral and tibial lengths and femoral width measurements have been made and correlated with body lengths; maximum running speeds and maximum horizontal pulling (= pushing) forces have also been made and correlated with body lengths. Galerita lecontei and Omophron labiatum have long femora, whereas those of Diplochila major are somewhat shorter and those of Scarites subterraneus and Morion monilicornis are very short. Scarites subterraneus has relatively narrow femora although there is a trend towards a narrowing of the femora in Morion monilicornis. Only Omophron labiatum has broad femora. Galerita lecontei and Omophron labiatum have long tibiae whereas Scarites subterraneus and Morion monilicornis have very short tibiae. Diplochila major represents the mainstream of carabids, with tibial lengths lying between the two extremes. All five species show morphological adaptations of their locomotory apparatus indicative of their locomotory abilities. In this study Omophron labiarum was found to be particularly fast at high speed running (i.e. sprinting) whereas Scarites subterraneus was found to be relatively slow. Only Scarites subterraneus showed particularly strong pushing abilities whereas Galerita lecontei was found to be weak at pushing. Omophron labiatum, Diplochila major and Morion monilicornis were found to have pushing abilities between the two extremes. Variations in height of the prothorax and hind body, the widths of the hind body, prothorax and metatergum, and the lengths of the metasternum, metatergum and wings are discussed and compared with body lengths in the five species. These various parameters have been displayed in the form of tables, and have been discussed in relation to the various habits of the five species. Certain trends were noted. Only Diplochila major has body proportions similar to those of mainstream cursorial carabids. Galerita lecontei has a shallow, narrow prothorax which may be correlated with its particular hunting habits. Scarites subterraneus has a somewhat cylindrical body form; the hind body is often narrower and flatter and the prothorax flatter than mainstream cursorial carabids. This kind of body form ...