On Aquatic Carnivorous Coleoptera or Dytiscidce. 



I. IL—Geims LACCOPHILUS. 



Prosternal process with unispinose extremity; spurs of hind tibiae emarginate at 

 their apex. Head ver}' short. 



The species* forming this aggregate are numerous and of extreme difficulty to 

 study and discriminate. Tlie most useful and natural method of arrangement 1 can 

 suggest at present is one based on the length of the prosternal process, and on the 

 presence or absence of a coxal file ; and in order to further facilitate reference I have 

 combined with this ai-rangement the fact whether the species are found in the 

 New or in the Old World. The species seem to inhabit more especially the warmer 

 parts of the world, and as I feel sure that not one-fourth of those existing are 

 known to us, I do not think it worth while at present to try and effect a more 

 detailed or truly natural classification of the species of the aggregate. The coxal file 

 when present consists of a series of very fine ridges, placed on a segment of a circle, 

 commencing near the middle of the body just where the coxal lines start from the 

 extremity of the metasternum, and from this point they extend outwards and 

 backwards so as to form a curved series of parallel furrows. The prosternal process 

 has the extremity very slender, so that in the species where it is elongate it is not 

 unfrequently broken off, but even in such a case its length can be estimated by that 

 of the groove for its reception on the anterior portion of the metasternum. 



* In addition to those enumerated in the text, tlie following also belong to the genus : — 

 Hydroporus inefBciens, Walk. (No. 1,382 huj. op.) ; Ceylon. 

 Laccophilus adspersus, Boh. (No. 1,474) ; Caffraria. 

 Laccojjhilus baeri, Regt. (No. 1,4T5); Manilla. 

 Laccophilus cayennensis, Aube (No. 1,47G) ; South .\iiioriea. 

 Laccophilus decoratus. Boh. (No 1,477); Manilla. 

 Laccophilus flavescens, Motsch. (No. 1,478); Ceylon. 

 Laccophilus hydaticoides, Regt. (No. 1,479); Manilla. 

 Laccophilus Uneatus, Aube (No. 1,480) ; Mauritius. 

 Laccophilus mexicanus, Aube (No. 1,481), 1 near No. 100; Mexico. 

 LaccophUus orientalis, Aube (No. 1,482), ? near No. 161 ; Java. 

 LaccophOus ornatus, Aub6 (No. 1,483), 1 near No. 118 ; South America. 

 Laccophilus poecilus, Klug (No. 1,484); Egj-pt. 

 Laccophilus proteus, Regt. (No. 1,485); Manilla. 

 Laccophilus pumilio, Lee. (No 1,486) ; North America. 

 Laccophilus quadrisignatus, Aube (No. 1 ,487) ; South America. 

 LaccophUus rivulosus, Klug (No. 1,488), 1 near No. 148 ; Madagascar. 

 Laccophilus strrehmi, Th. (No. 1,489), 1 No. 128 var. ; Finland. 

 Laccophilus transversalis, Regt. (No. 1,490); Manilla. 

 Laccophilus transversus, Motsch. (No. 1,491); Burmah. 

 Laccophilus umbrinus, Motsch. (No. 1,492); Egypt. 

 Laccophilus uniformis, Motsch. (No. 1,493) ; India. 

 Laccophilus vermiculosus, Gei-st. (No. 1,494); East Africa. 

 Laccophilus yvictse, Le Guill. (No. 1,495 ; Chili. 



