1916. | F. H. GRAVELY : Lignicolous Beetle-Larvae. 139 
Leptaulax bicolor (Fabricius). 
1861, Candéze, E. ‘‘ Histoire des Métamorphoses de quelques 
Coléoptéres exotiques.”’ Mem. Soc. R. Sct. Liege, XVI, 
1861 (‘‘ Passalus,” pp. 343-344). 
Passalid larvae are all much alike, and Schipdte’s elaborate des- 
cription of the larva of ‘‘ Passalus cornutus”’ will probably be found 
to apply to all so far as general structure is concerned. Only 
specific differences, therefore, will be described here. Candéze 
was unable to detect any definite differences between the species 
before him, beyond slight ones in the position of the stigmata. 
In Oriental forms specific differences are found in the arrange- 
ment and nature of the large hairs, and in the manner in which, if 
at all, pile is developed on the body. 
Among the larvae I have examined all those with definite pile 
belong to the Pleuvarius, Aceraius and Macrolinus groups, and in 
the first of these it is confined to the later stages while in the 
second it is absent in one species. Probably, therefore, the 
development of pile is a departure from the primitive type of larva. 
In this connection it is noteworthy that the larva of the Aceraius 
group from which it is absent—Z pisphenus neelgherriensis—is that 
of the most primitive beetle of this group whose larva I have seen ; 
also that the larvae of the two Bornean species of Aceraius examined 
have the pile better developed than those of the two from conti- 
nental Asia, although one of the latter is the northern race of the 
highly specialized dominant species of the genus (compare Journ. 
As. Soc. Bengal, [n.s.| X, pp. 201-210, pl. xxiv; or Mem. Ind. 
Mus, Ii wo, 311-313, text-fig. 7 p2gr4): 
The manner in which the larger hairs are distributed appears to 
be derived by the suppression or multiplication of particular hairs 
from the following generalized plan.! A short row (usually five) 
behind each antenna on the head; a short row (usually three includ- 
ing the lateral hair) bordering each of the anterior angles of the first 
thoracic segment; one pair of dorsal hairs on each segment in front 
of the tenth abdominal ; one pair of lateral hairs situated obliquely 
above and behind the stigmata, and directiy below but somewhat 
further away from the dorsal pair of hairs on each of these seg- 
ments; one pair of ventral hairs in the same vertical plane but 
situated obliquely behind and below the stigmata on each of these 
segments after the first two thoracic, and especially on the ninth 
abdominal; a circumanal ring, usually of about seven pairs of hairs, 
on the tenth abdominal segment. : 
It is noteworthy that, in these characters also, E Mana 
neelgherriensts approaches the generalized type more nearly than do 
any of the more highly specialized members of the Aceraius group 
that I have examined; and that in this and some other oa 


! Only in certain species of the highly specialized genus Acerazus are hairs 
produced in an entirely fresh place, namely on the frons. 
