THE PRIONID^. 283 



developement than in the tribe where this structure is 

 universally prevalent. On the analogy, or rather the 

 affinity, between the PrionidcB and the LucanidcB we have 

 already stated quite sufficient; as well as on those reasons 

 which makes the Buprestidee, however obscurely, the 

 representatives of the Curculionidce. As for the last in 

 our series, wherein the Bostrichidcp sta.nd opposite to the 

 Hydrophilidtp, the same uncertainty exists in this as in 

 the preceding table. If Latreille's Sagrides really fill 

 this station, our difficulty would be removed, since those 

 insects present two tangible points of analogy both to 

 the Hydrophilidce and the DyticidcB; one, in the great 

 developement of their posterior legs, and the other in their 

 aquatic habits. LatreUle remarks that the Donacite, 

 in their larva state, live on the internal parts of the roots 

 of those aquatic plants upon which the perfect insect 

 feeds ; so that in their larva state they are as decidedly 

 aquatic as any of the true water beetles. On the other 

 hand, these analogies may be all perfectly true, and yet 

 the Sagrides may hereafter prove to be no other than 

 some aquatic type within the circle of the Monilicornes, 

 and as such, also, we shall subsequently treat them. 



(254.) Our first family, the Prionid^, contains, as 

 we have before observed, many of the most gigantic of 

 the Coleoptera. As the term is rather indefinite, a dis- 

 tinct idea will be conveyed, when we say that the Ti- 

 tanus gigas is frequently eight inches long, exclusive of 

 the antennte ; and the Prionus HayesH of Mr. Hope, 

 evidently closely allied to the genus Macrotoma, is four 

 and a half inches in body, but, including its antennae, it is 

 nearly a foot long. There is considerable variation in 

 the structure of these organs in the family before us : 

 that which is most typical, and which occurs chiefly in 

 the genus Prionus itself, is to have them pectinated; 

 although in the larger genera, as Titanus, Enoplocerus, 

 Ctenoscelis, &c., they are filiform : but it must be ob- 

 served, that what is technically called serrated arises 

 from the gradual enlargement from base to apex of 

 each successive joint of the organ, and not from the 



