350 



NATURAL HISTORY. 



other allied species destructive to cruciferous plants. In temperate latitudes none but species of small 

 and even minute size are met with, the latter resembling fleas in their dimensions and great agility in 

 leaping ; but in the tropics much larger and more brightly-coloured and variegated forms swarm on 

 bushes and herbaceous vegetation. The fourth and last section are the CRYPTOSTOM.E, distinguished 

 by the forehead being inflected downwards, bringing the mouth (which is much reduced in all its 

 dimensions) to the under surface of the head, and also by the claw-joint of the tarsi scarcely project- 

 ing beyond the lobes of the third joint. The antennae are short, and very often straight and rigid. 

 To this section belong two sub-families, Hispiim and Cassidince, which run into eccentric and striking 

 forms, the thorax and elytra of the Hispince, in their extreme developments, being studded with spines, 

 and the same parts in the Cassidinai being laterally expanded, so as to cover the head and trunk as 



LINA POPULI. 



with a rounded shield. These extreme forms are placed naturally by all entomologists who have 

 classified the groups at the end of the two respective sub-families, so that the classification in each 

 begins with species which partake of the characters of both, and is carried on through the very 

 numerous genera and species, pretty gradually receding on each hand from the common type. 

 Thirteen species of the genus Cassida are met with in England, two of which are not uncommon on 

 thistles in summer, on which plants the curious habits of the larvae may be studied, protected as they 

 feed by a little mass of their own excrement, secured by a horny forked process at their tails. Some 

 of the native British species of Cassida are ornamented with bright silvery streaks or markings, which, 

 however, give but a faint idea of the extreme brilliancy of many tropical ones, some of which resemble 

 beads of polished gold or silver, and others, of more pearly lustre, glitter on the leaves like drops of 

 dew in the morning sun. 



TRIBE EROTYLIDES. 



This group differs from the preceding in many important characters, and belongs but imperfectly 

 to the Tetramera section, many of its genera having a conspicuous fourth joint to the tarsi, and the 

 antennae being terminated by a distinct club, as in the more typical genera of the Clavicornia tribe. 

 All the species, upwards of 1,000 in number, live on fungi or boleti, and have smooth integu- 



