ON HYDR0BIV8 AND ALLIED GENERA. 
BY D. SHAEP, M.B. 
me impressed with the lacx ii F discordant 
J r^.1 Iw Mulsant, Laeordaire and Duvai) are very m 
.nderstuodbyMulsant impression so gamed, I 
.cies or appearance; ^^^^'^^^ external anatomy of these in- 
, made careful e--^^-^ f ^^^^^^^ I ,ave found that an 
^ ''-' ''': :ftLreXs o' tie:: tnera, in accordance with their 
,,gement of ^^^^P^;^^" ^ ^^^ ;, regards their anatomical and 
es, would f o ^^^^f^iri thint it will be well to adopt 
eric characters. ihe divisio . ^y Thomson in his 
„ac«.v in '^■^;:^;^^^^:j:'''^XSe!X cLaeters given fo. 
,»ai„avieos Co eopt^^ a. As, ho^^^ ^. ^^^^ ^^^^^^^ ^^ 
..,, d,vis,onB bj ''»* '^J ^^ ted m such catalogues as have 
J as his genera have not been yet aQ p ^^ ^^ ^^^ 
,n published since h.s work appeared; ^'^'J^Jlo^Ms. I am not 
J,, of these genera. ayjeuse^^^^^^^ 
nminted With the exotic species ui j . ;i 
^to prove the validity of the divisions here adopted. 
Htdbobitts, Leach. 
1 _„a.illa and max. palpus of Hydrobius fuscipe,. 
^^-I'^axiUal'' max. palpu. of Heloc'.ares lividus. 
f Im'LilT, aUTax. palpus of PUUhydrus melanocephalus. 
nlnlxuTa and max. palpus of Er.ocHrus Hcolor. 
4a— labium of ditto. , Parcacumus ameui. 
I Z^'mto ' "''dittf ^"«<^«»« S'"^"""- 
6a -labium of ditto. 
Of an oblong-oval ( 
form. Mesosternum 
carinated in the mid- 
dle, in front of the 
intermediate coxae. 
Tibias strongly spinu- 
lose. Maxillary palpi 
moderately long, the 
third joint shorter 
than the second or 
fourth, which are of 
about equal lengths ; 
labial palpi mode- 
rately long and mode- 
^rately stout, the se- 
cond joint longer than 
the third. 
Two British 
species ; fuscipes 
and oUongus. 
