Parnus.] CLAVICORNIA. 383 



(P. lutulentus, Er. This species has found its way into some of our 

 lists, but does not appear to rest on sufficient authority ; it is oblong 

 and somewhat depressed, black, clothed with very thick yellowish 

 pubescence intermingled with short grey hairs, and may be recognized 

 by the rows of punctured striae on the elytra, which are feeble but 

 regular, and traceable to apex ; the species is much larger than P. 

 algi'ricus, the striation is weaker, and the pubescence is yellower. L. 

 4-4| mm.) 



HETEROCERIDJE. 



This family consists of a single genus, Heterocerus ; its true position 

 is somewhat doubtful, as it does not appear to bear a very marked 

 affinity to any particular family ; in their amphibious and subatjuatic 

 habits the species resemble the Parnidae, and in their densely pubescent 

 surface, very short antennae, and general shape are not unlike certain 

 species of Purnus, although they differ entirely from them on a closer 

 examination ; perhaps, however, taking all things into consideration, it 

 is best to place them near the Parnidae, and, as an aberrant family, 

 they may be with advantage placed at the end of the Clavicorn series ; 

 the following are the chief characteristics of the family : head large, 

 front prominent, antennae short, inserted above the base of the man- 

 dibles near the inner margin of the eyes, 11-jointed, with the two first 

 joints large, and the remainder forming an oblong serrate club ; eyes 

 half hidden by the thorax ; thorax transverse, with the sides at most 

 margined only behind, free at base, and not fitting closely to elytra, 

 with all the angles rounded ; anterior coxal cavities open behind ; 

 mesosternum very short, metasternum moderate ; elytra covering abdo- 

 men ; abdomen composed of five segments, of which the last two are 

 free and the others connate ; legs fossorial, tibias dilated and armed 

 with spines, tarsi short, 5 jointed, according to some authors 4- jointed, 

 the first joint being very minute (and so, often overlooked), capable of 

 being folded back upon the tibise when these are used for digging ; 

 anterior coxae transverse with distinct trochautin, posterior 00x33 nearly 

 contiguous at base ; on each side of the first segment of the abdomen 

 is an elevated curved line reaching the posterior margin ; this elevated 

 line is finely striate transversely, and according to Dr. Horn is a stridu- 

 lating organ, the hind legs by friction against it producing quite a 

 distinct sound. 



The larva of Heterocerus is figured by Westwood (Classific. i. p. 113, fig. 7, 5) ; 

 it is quite as anomalous as the perfect insect, and most resembles an inverted 

 teetotum ; the head is large, with strong toothed mandibles, behind which the eyes, 

 which are small, are .situated ; the three thoracic segments are abnormally large, 

 nearly twice as broad as the head, and very transverse ; the abdominal segments are 

 nine in number, and very much narrower than the thoracic segments, the last being 

 longer than the rest ; they are slightly narrowed towards apex, and are subcylin- 

 drical ; the body is strongly setose, and the legs are stout and strong, and armed 

 with a single claw ; the larva occurs in the same situations as the perfect insect. 



