COLEOPTERA. 



those of the males being larger, longer, or laterally 

 more developed than in the other sex, The eyes, 

 which are always composite and facetted, are gene- 

 rally larger and globular in the carnivorous species, 

 as well as in those which, from the slowness of their 

 habits, have great need of defence against their 

 enemies. Some species have been asserted to possess 

 the simple eyes (ocelli'), observed in the hymenoptera, 

 &c. ; but Latreille does not consider that any species 

 possesses these organs ; and indeed, as he is induced 

 to suppose from a comparative examination of the 

 eyes of insects, that the presence of these ocelli is 

 an indication of optical weakness, their non-existence 

 in the coleoptera seems to confirm his opinion of the 

 superiority of these over other insects. The mouth 

 consists, as in all masticating insects, of an upper lip 

 (labrum, ), a pair of horny jaws moving horizontally 

 (mandibles, b), two other jaws (maxilles, c) of a less 

 firm consistence, but more complex in their organi- 

 sation, bearing a palpus (rf) or feeler, and furnished 

 moreover with a lateral lobe, which occasionally 

 assumes the appearance of an additional palpus, and 

 lastly a lower lip (labium, e), furnished with a pair of 

 palpi (/), and implanted upon a broad horny basal 

 piece, which is termed the chin or mentum (g). 



The thorax, as usual, consists of three segments, 

 but the first of them, or the prothorax, is so much 

 developed at the expense of the second and third, 

 that the only conspicuous part in the meso-thorax 

 (or second segment), is the part usually termed the 

 scutellurn, whilst the meta-thorax (or third segment) 

 is reduced to a short and almost obsolete ring, giving 

 support to the pair of wings and the third pair of legs. 

 The legs articulate with the posterior extremity of 

 the segments, to which they are attached beneath, by 

 means of a short piece termed the trochanter, which 

 in the hind legs is more voluminous, forming indeed, 

 occasionally, a large plate, sometimes moveable, but 

 at others soldered to the segment, of which it appears 

 to form a part ; indeed in the water beetles, the large 

 trochanters of the hind legs have been mistaken by 

 some of our first entomologists for the sternum ; this 

 piece is followed by another email joint, the coxa, 

 which is succeeded by the femur or thigh, which is 

 the strongest part of the leg, and the tibia or shank, 

 a piece generally of nearly equal length with, but 

 more slender than, the preceding, the last portion of 

 the leg consisting in an articulated piece called the 

 tarsus, the number of articulations of which varies 

 from three to five. The abdomen is attached to the 

 meso-thorax by its entire breadth, its inferior portion 

 or the belly being always more solid in its consistence 

 than the upper surface, owing to the latter being 

 defended by the wing covers; it is moreover pro- 

 vided on the under side with only six segments, 

 whPst on the upper seven or eight are visible. In 

 gome insects, however, as the rove beetles (Brack- 



elytra), which have the abdomen for the most part 

 exposed, the upper surface is as firm as the lower. 

 The additional segments of the body, two or three 

 in number, which are to be observed in the body of 

 the larva, compose, in the perfect beetle, the organs 

 of generation. 



The metamorphosis of the coleoptera, or rather its 

 character, as derived from the state of the pupa;, is 

 termed incomplete. The larva resembles a soft fleshy 

 worm, having the head and upper surface of the tho- 

 racic segments scaly, and provided with six legs, 

 attached in pairs to the three anterior segments of 

 the body. The head of the larva exhibits, in an un- 

 developed manner, nearly all the parts of the mouth 

 of the perfect insect. In the place of the facetted 

 eyes, are to be seen a number of small granular 

 tubercles, which somewhat resemble the ocelli of the 

 hymenoptera, &c., being often six in number on each 

 side of the head. The jaws are much more developed 

 than the other parts of the mouth, which is doubtless 

 owing to the circumstance, that it is in the larva 

 state that the greatest supply of nourishment is taken 

 by the insect. The antennae are very small and 

 conical, and generally only four-jointed. The more 

 inactive and concealed these larvae are, the more they 

 exhibit the appearance of a worm ; those of the more 

 carnivorous species are generally more alert, and in 

 the rove beetles we have seen that they exhibit very 

 much of the appearance of the perfect insect. The 

 extremity of the body of these larvae is often furnished 

 with a fleshy retractile tubercle on its under side, 

 which is employed as a seventh leg. When the 

 larva has attained its full size, it generally burrows 

 into the earth, where it hollows out an oval cell, 

 within which it is transformed into an inactive pupa, 

 of an uniform whitish colour, with the wings and legs 

 folded upon the breast. The pupae of some of the 

 species are, however, naked, as in the Chrysomelidce, 

 whilst others, as Clythra, pass this state within the 

 case which had served for their abode whilst larvae. 

 The duration of these transformations, the habitations 

 and economy both of the larvae and perfect insect, 

 varies, as may well be supposed, in so extensive a 

 group, in the different families and genera. Arrived 

 at their last state, they possess their full degree of 

 development, and now the reproduction of their 

 kind is their chief employment. 



Compared, however, with many other tribes of 

 insects, as for instance the bees, ants, wasps, ant-lions, 

 &c., none or but very few beetles present in their 

 habits any of those extraordinary traits of instinct 

 which have so much engaged the attention of obser- 

 vers in every age and country ; still, however, even in 

 this respect they are not without interest, as we have 

 already seen in the articles CICINDELID^E, COCCINEL- 

 LID.K, CERAMBYCID^E, &c., and as we shall have to 

 show in many other instances. 



Hardly any coleopterous insect has been employed 

 in the arts, but it is questionable whether some of the 

 species might not be rendered useful. The meloe 

 and the coccinella emit from the mouth and eyes a 

 gummy fluid of a fine yellow colour, which might be 

 employed in painting. The former insect is of a 

 large size, and sufficiently abundant for experiment, 

 if some of our celebrated chemists would not think 

 the subject beneath their notice. In like manner tho 

 Mylabris, Cantharis, or Carabus, might furnish an use 

 ful extract of a fine colour. We have already in our 

 articles upon these insects given an account of their 



