] CLAVICOKXIA. 47 



closely allied species at the roots of wild plants on the side of cliffs in the Isle of 

 Wight, and if the larva at one period of its existence is a plant-feeder, there is no 

 reason why it should not be so from the time it hatches out of the egg ; the insect 

 appears only to attack the leaves, and not to affect the root directly ; if, therefore, 

 the field is left to itself, it may recover after the larvae have all assumed the pupa 

 stage, which happens about the beginning of July. 



The larvae of Silpha rugosa and S. obscura are described and figured by Schiodte I. 

 p. 35, PI. IX. i. 15; they are very different in shape, the former being much more 

 elongate than the latter, with the angles of the thoracic segments rounded, and those 

 of the abdominal segments strongly produced ; the prothoracic segment is not much 

 narrower in front than behind, and the cerci are three times as long as the anal 

 appendage ; the larva of 8. obscura is broad in front and narrowed behind, almost 

 shield-shaped, with the prothorax very large, semicircular, with posterior angles 

 blunt ; all the other segments except the tenth are strongly produced at the posterior 

 angles, and become gradually narrower ; the tenth is broad aud snbquadrate, and 

 bears a short blunt anal appendage and two short cerci ; the head, which in the 

 larva of S. rugosa, is rather large and projecting, is almost concealed behind the 

 thorax, and the antennae are much longer than in this latter species ; their appearance 

 rather tends to prove that the species are, as they are regarded by many authors, 

 generically distinct. 



I. Thorax truncate or emarginate in front; head not 



elongate ; mandibles not produced, 

 i. Intermediate coxsa not widely separated ; elytra in 

 both sexes rounded together at apex. 



1. Head moderately or slightly contracted behind 



eyes; labrum moderately emarginate. 



A. Antennae with club not strongly marked, and 

 with second joint equal to third ; tibiae straight ; 



colour uuicolorous black (in our species) . . . SILPHA, i. sp. (Para- 



sll.pha, Reitter). 



B. Antennas with club strongly marked, and with 

 second joint longer than third ; tibiae curved, 

 more so in the male than in the female; elytra 

 reddish testaceous, with two black spots on each 



(in our species) DENDROXENA, Mots. 



(Xylodrepa, Thorns.). 



2. Head short and broad, not narrowed at all behind 



eyes; labruin emarginate to base (Oiceoptoma, 

 Leach). 



A. Antennae with very gradual club, seventh joint 

 very little narrower than eighth, second joint quite 



twice as long as third ACLYPEA, Reitter. 



B. Antennae with well-marked club, seventh joint 

 much narrower than eighth, second joint about a 



quarter longer than third BLITOPHAGA, Reitter. 



ii. Intermediate coxae very widely separated ; elytra 

 with the sutural angle produced in female; antennae 



with second joint shorter than third THANATOPHILUS, Leach. 



(Paeudopelta, Reitter). 



II. Thorax forming a complete semicircle ; head much 

 longer than broad ; mandibles produced. 



i. Antennae very short and stout ; elytra smooth ; legs 



stout, with tibiae widened towards apex ABLATTABIA, Reitter. 



ii. Antennae long and slender ; elytra ribbed ; legs 



slender i PHOSPHUGA, Leach. 



(Peltis, Reitter, 

 nee auct.). 



