102 [October, 



4th to Gth together shorter than 2ncl and 3rd iniited, gradually wider, 7th about as 

 long as the 2nd and 3rd united, elongate oral, scarcely wider than the 6th, with au 

 indistinct transverse suture near the base, and another very near the tip, which is 

 sub-acute. 



"Labrum transverse, rounded in front concealing the mandibles. Maxillfe 

 large at the base (lobes not examined), maxillary palpi less than half as long as the 

 antennae, Ist and 4th joints long, 2nd and 3rd vmited equal to either of the others, 

 not dilated ; mentum trapezoidal, rather large, broader than long, wider in front ; 

 ligula rather large, eniarginate, palpi short, rather stout, 2nd and 3rd joints broader 

 and shorter than the 1st. 



" Presternum very short, hardly visible, front coxse transversely conical, conti- 

 guous, trochanters large, cavities narrowly closed behind ; middle coxro separated;; 

 small, mesosternxim protuberant ; metasternum large, side-pieces narrower and 

 pointed behind, hind coxae widely separated, laminate, the plate curved in arc of 

 circle behind, and half as long as the Ist ventral. 



" Abdomen conical, with six free segments, 1st large, longer than the four fol- 

 lowing united, which are equal in length, but rapidly narrower ; Gth equal to the 

 four preceding united, rather longer than wide, concave and emarginate behind, with 

 two anal filaments equal in length to the segment itself. 



" Legs short, front tibise somewhat thickened at tip ; tarsi slender, rather shorter 

 than tibiae, apparently 4-jointed, Ist and 2nd joints short, 3rd equal to them united, 

 4th equal to the others imited, claws rather long and slender. 



" Body small, scaphiform, rounded in front, nan-owed behind, convex, elongate, 

 and shining. Head rather large ; prothorax nawower in front, with dcflexed angles, 

 base truncate, not margined. Scutellum small. Elytra without striae, slightly 

 punctulate, broadly truncate at tip. Abdomen projecting somewhat behind the 

 elytra, with three segments visible, conical, not margined at the sides. 



" H. NATANS. — Oval, narrower behind, convex, black or brown, shining ; head 

 and prothorax nearly smooth, elytra sparsely and finely punctulate ; an- 

 tenna; and legs testaceous. Length, less than '5 mm., = "02 inch.* 



" Found abundantly by Mr. Crotch at Los Angeles in the river. Mr. Crotch 

 informs me that this very singular insect resembles in appearance some of the species 

 oi Limnelius. It greatly differs from that genus, as from all other Hydrophilidce , 

 by the laminate and widely separate hind coxae, and by the peculiar abdomen. It 

 seems to me another of the synthetic types gi'adually becoming known to us among 

 the smaller and more obscure fonns, connecting several different families of the 

 Clavicorn scries ; in this instance, the Si/drophilidce, Scaphidiidce, and perhaps the 

 Trichoptert/gidce. In the accepted aiTaugement of Coleoptera, it must bo considered 

 as indicating a new family." — Lcconte. 



I have made a tolerably careful examination of the specimens of 

 tlie above insect sent to me by its able dcscriber. So far as I can 

 follow bis description, I am enabled to confirm it, with tbe exception 

 of one or two points. I bavo convinced myself fully that the antennje 

 of the above described JET. nutans arc eight-jointed, and the tarsi only 

 three-jointed. Considering this latter point of importance, I have 



* This i.s, of course, a misprint ; the spccimciis sent by Dr. Lcconte are about half a line in 

 leugth, = 04 inch.— n. S. 



