134 PARNIDZ. 
hand, Leconte and Horn have rejected Limnius as not distinct from Hlmis by suffi- 
ciently important characters; and the Munich Catalogue of Coleoptera suppresses 
Lareynia, while admitting Limnius. More recently, Mulsant and Rey (Hist. Nat. Col. 
Fr., Unciféres) have divided the European species of Himis into six genera; while, 
again, King (Trans. Ent. Soc. N. S. Wales, 1865) has described from Australia, under 
the generic names Himis and Limnius, certain species which would clearly have to be 
separated from the European genera so named if we presumed, as King has done, the 
characters by which the two genera just named are separated to be valid. A comparison 
of the Central-American insects with the European forms reveals considerable differ- 
ences ; but great diversity of structure among the former is also seen, and it would, I 
believe, be the proper course to make several new genera for these Central-American 
Himides: this task the material before me, consisting largely of unique individuals, ren- 
ders almost impossible; and in view of all the facts I have decided on using the generic 
name lmis in the more extended sense suggested by Leconte and Horn, a course 
which will at any rate possess the advantage of placing the Central-American and 
North-American species on a similar footing. I have, however, separated certain forms 
which could not be included in E/mis without rendering invalid other genera that are 
still adopted, such as Stenelmis and Cylla@pus. In this extended sense Hlmis will com- 
prise at present about fifty species, of which more than half are European, fifteen North- 
American, a few Australian, two being from Chiliand Peru. The species of the southern 
portions of the United States have been but little collected, and none are known from 
Mexico ; but no doubt botii these regions will in due course furnish a fair contingent of 
species., The insects of this genus live, without exception, on stones in running waters ; 
and now that Mr. Champion has discovered so many species in Central America, we 
may anticipate that the waters of the hilly regions of the tropics will, when searched 
for the purpose, yield a considerable fauna of these insects. 
1. Elmis championi. (Tab. IV. fig. 12.) 
Elongatus, angustulus, anterius angustatus, nigro-fuscus, opacus, antennis pedibusque rufis ; prothorace utrinque 
linea elevata arguta; elytris vix striatis, sed fortiter seriatim punctatis, punctis versus apicem obsoletis, 
interstitiis granulatis, utrinque versus latus linea elevata a basi ad apicem ducta. 
Long. 13, lat. 3 lin. 
Hab. Panama, Volcan de Chiriqui 2000 to 3000 feet (Champion). 
Rather narrow, little convex, elongate, and thus similar in form to the European 
Elmis angustatus. Antenne rather elongate, clear red. Thorax very opaque, but 
without granulation or punctuation; the sides narrowed in front, the lateral margin 
coarse, crenulate, the hind angles a little raised, so that there appears to be a depression 
in front of them ; on each side a very conspicuous elevated line that becomes obsolete 
at the front margin. Elytra with rows of coarse punctures that become quite obsolete 
on the apical portion, also rather finely granulate, and with a fine but very definite 
elevated line extending from the shoulder to the extremity. 
