THE CARNIVOROUS GROUND-BEETLES. 



305 



readily assume the dormant condition ; this enables them to withstand extremes of temperature, 

 and to flourish in a great diversity of climates and situations. In cold climates their favourite winter 

 retreat is in beds of moss ; and they may be found in numbers in England in such situations, on 

 sloping banks and at the foot of trees, where moisture does not accumulate, throughout the winter. 

 On the other hand, in arid, sandy tracts in Australia and Africa, where so many tine species occur, 

 they no doubt pass the great heats of the dry season in burrows or sheltered places at the roots of 

 brushwood, for they are quite as sensitive to heat as they are to cold. Even in cool countries like 

 Britain they are very rarely seen abroad in hot and dry summer weather ; and in the tropics, during 

 the many months of the dry season, they all disappear, to come forth only with the return of the 

 rains. 



The means of defence from their enemies possessed by the Carabidse are less varied than in most 

 other families of Beetles. They have generally great speed of foot, and many of them take wing 

 readily enough, or conceal themselves rapidly among herbage, but cases of protective disguises or 

 mimicry are unknown or very doubtful ; this applies even to the simplest form of disguise, assimilation 

 of foi-m and colour to the material of their surroundings. This deficiency seems to be made good by 

 the faculty which they possess of secreting an acrid, or foetid, liquid from the anus, which is effected 

 by means of special glands. The liquid is ejected sometimes with force when the insect is handled ; 

 and in one well-known group the Brachini the secretion is volatilised, and issues forth as a little 

 cloud of smoke. The Brachinus crepitans, a common insect under stones in the South of England, 

 has been observed to discharge its singular weapon when pursued by an insect enemy ; and it derives 

 from this habit its popular name of "Artillery-beetle." A slight sound is sometimes audible when one 

 of the Beetles fires its mimic gun whilst held in the fingers. The explosion and its effects are, 

 however, very much stronger in some of the large exotic species, such as the South American 

 Pherosopkus complanatus, which, when caught, will often crepitate quite loudly several times in 

 succession, and cause a burning sensation in the fingers, which are stained brown where the vapour 

 has touched them. 



The vast host of specific forms of which the family Carabidae is composed gi-oup themselves naturally 

 under two divisions, founded on an important difference in the framework of the sternum, or breast. 

 The difference is this : in one set of forms, constituting the first division, the hindmost of the three 

 side-plates of the middle thorax (mesothoracic epimera) reach inwardly to the 

 sockets of the haunches of the middle pair of legs in the other set, forming 

 the second division, they stop short, so that the orbit of the sockets is tightly 

 closed by the meeting of the central-plates of the middle and hind thorax. 

 Although the physiological importance of this difference can be only small, 

 perhaps tending to a little more compactness of structure and precision of 

 movement in the one form than in the other, the morphological significance 

 is very great, for it is found that all the genera allied in other respects to the 

 two neighbouring families, Cicindelidse and Dyticidse, belong to the first divi- 

 sion, and all the highly specialised forms of pure Carabideous type belong to the 

 second. The forms of the first division are therefore nearer the fundamental 

 common type of the Adephaga than those of the second. 



The first division is well represented in temperate latitudes. It compi-e- 

 hends all the true Carabi and the Calosoina;, large insects, remarkable for their ' 

 generally brilliant metallic colours and elegant sculpture, the elytra being often 

 scored with fine punctured lines, between raised interstices, which are con- 

 solidated in some species into a smaller number of rib-like elevations, and again 

 in others are broken up into rows of tubercles. Of the genus Carabus, about 

 400 species are known. A good idea of their form may be gathered from 

 our illustrations, in one of which are represented two individuals of Carabus 

 auratus, a common French species, sometimes found on the south coast of England. One of the 

 Beetles is engaged in disembowelling a Cockchafer, whilst one of the two larvae is seizing an 

 Ant. Our other illustration represents Carabus adonis, a large species of a rich violet colour, with 

 golden borders to the wing-cases, which is found only on the classical Mount Olympus, in Thessaly. 

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CARABUS ADONIS. 



