NECROPHAGA AND THEIR ALLIES. 
135 
rugineus enters into the holes made in the wood of 
fir-trees by certain species of Xylophaga, and lays 
eggs in their galleries ; its larvae feeding on those of 
the latter insects, and, being of slower development, 
taking more than a year to transform. 
The females in this genus, as in Cryptarcha, have 
the elytra rather pointed at the apex. 
The RMzophagina have the antennae apparently 
ten-jointed, with the club solid, the eleventh joint 
being merged in the tenth, and the tarsi dissimilar 
in the sexes, heteromerous in the males, and all five- 
jointed in the females ; the species of our single 
British genus, Rhizophagus, have the anterior coxal 
cavities completely closed behind, and the males have 
a small additional segment to the abdomen. They 
are small, linear insects; chiefly found under bark, 
though some occur in ants’ nests, and others in bones, 
&c. The larva appears to be like that of Soronia 
grisea above described, in miniature. M. Perris states 
that ho has observed the larvte of R- depresses to 
have similar habits to those of Ips ferruginous', and 
that more than once he has seen two or three of the 
larvae with half their bodies plunged into the larvae 
or pupae of Hylesinus or Hylastes , devouring them. 
He has also taken home the larva) of both Rhizophagus 
and Ilylesinus, and often not one of the latter escaped 
being eaten. 
The Rhizophagus appeared to turn to pupa in the 
ground, and not under the bark. 
The Tkogositidao have two lobes to the maxillae ; 
the tarsi five-jointed, simple, and with the first joint 
very small ; and the elytra covering the abdomen. 
The apical joint of the tarsi is also very long, and 
has between its claws a small and slender styliform 
