126 THE ORDER OF COLEOPTERA. 



excavatum are shining black species, the latter being distiugiiished by 

 two short horns on the head of the male; the Jiavipes is known by its 

 bluish pruinose surface and yellow legs ; and the elijjticum, common in 

 the Southern States, which is readily distinguished by the oblique red 

 spot on the anterior part of each elytron. 



Section III. TETRAMERA. 



Apparently four joints in all the tarsi ,- the joints dilated and brush-like beneath, with the 

 penultimate usually bi-lobed. 



The structure of the tarsi in this section is very uniform, being always 

 composed of four distinct joints, with a faint rudiment of the missing 

 joint at the base of the last. • We have seen above that in some very 

 small species of the pentamerous section, one or more of the tarsal joints 

 are rudimental or wanting; but it is a curious fact, which may have 

 some important bearing in the classification of these insects, that in the 

 small Pentamera with deficient tarsi, it is usually the first joint which 

 is in a rudimental state, whilst in the genuine Tetramera it is always 

 the fourth joint that is undeveloped. The joints are dilated and cush- 

 ioned beneath with a dense brush of hairs (except the Scolytidre), and 

 the last joint but one is almost always bilobed, with the last joint in- 

 serted between the lobes. But in some of the (Jhrysomelides proper, 

 the penultimate joint, though dilated as usual, is entire or only slightly 

 notched at the end. The dilated, cushioned and bi-lobed tarsi are pe- 

 culiar to the beetles of this section with a few exceptions, and therefore 

 serve readily to distinguish them, independently of the number of tarsal 

 joints. This structure of the feet, as we have elsewhere remarked, seems 

 to be specially adapted to enabling these insects to adhere to the sur- 

 face of leaves and smooth bark, and accordingly all the numerous spe- 

 cies of this section are vegetable feeders. Many of them feed upon 

 foliage, some bore into the trunks or branches of trees, and others feed 

 upon fruits or seeds. This section, therefore, embraces a greater number 

 of species injurious to the agriculturist, than all the other sections com- 

 bined. 



The larvnB vary considerably in the different tribes, and will be de- 

 scribed in their i)roper connections. It may be stated generally, that 

 in those which reside in Avood or in fruits the feet are usually wanting, 

 or at most are merely rudimental, whilst those which live upon the sur- 

 face of leaves have six small but well developed feet. 



The beetles with four-jointed feet are divided into four tribes, as fol- 

 lows: 



Tribe 1st (or 16th of the whole number). Snout-beetles or Weevils. 

 Fructioora rostrata. KhyncophorAj Latreille. Head more or less pro- 



