520 INSECTA. 



First,— Those with very sliort 10 or U-juiiited aiiteiin;u, the third ami fullowin;,^ joints fonniii;; a subr\ lindncil, 

 serrated inass. 



Potamophilus, Germ. {Hi/derGf Latr.), have the antennre not lodged in cavities, and rather long;er than the liead, 

 with ttie tirst joint nearly as long as all the rest, and the isecoud short and globular ; the palpi are exserted and the 

 mouth is naked. Pnriuis acumhintns, Fahi". 



DnjopfifOVvi., has the antennce shorter than the head, and received in a cavity benrath the eyes, neaiiy covered by 

 the second joint, which is Iarf:;;e, dilated, and eai--like ; tlic palpi are not exserted. Leach applies this generic name to 

 Dryops DumerilH, which dill'ers from the others (which he names Parnm) in the length of the feet and form of the 

 thorax, &c. 



Second, —Those with dliforni U-jointed antennae, at least as long as the liead and thorax. 



Ehnis, Lat. [Liiiiiiiin; III.), [insects of very small size], found in wati.T, understijues, or the leaves of the water-lily. 



Third, — Those with very short 9 or 6-jointed antenna?, terminated in a nearly solid, oval, or ;jlobular mass. 



Macrotnjchus, Mull., has five distinct joints in the tarsi, the body oblong and antenna; G-jointed. M. i-htbcrcii- 

 7at}is, iMiiIl. 



Gcoi'i.sst/.'i, Latr., has only fmr distinct j(,iints in the tarsi, the body sliort and nearly ;,^lobular, and the autenn.'c 

 9-jointed. Plmclla pyijiiufay Fab., [a very minute shining black insect, with deep rows of dots on the el\ tra ; 

 rather rare]. 



THE FIFTH FAMILY OF THE COLEOFTERA FENTA^IERA,— 

 The PALi'icoRXEy, — 

 Possesses, like the last, antennrc terminated in a cliil), wliioli is ordinarily perfollatcrl, luit of not more 

 than nine joints in any species, inserted Ijcneatli tlie latend and advanced margins of the liead ; never 

 longer tlian it and tlie maxillary jtalpi, and often sln:)rter than the last-named organs ; the inentum is 

 large and sliield-sbaped. The body is generally ovdid, or hemispherical and convex. The feet are in 

 the majority proper for swimming, and have onl\' four or five distinct joints, the Ijasal juiat lieing 

 much shorter than the following ; all the joints are entire. 



Those species uhicb have the feet fitted for swimming, "with the basal joint of the tarsi much 

 shorter than the following, and the maxillae entirely corneous, compose a first tribe, Ilydrophill, which 

 embraces the genus 



IIvDROPHiLus, Geoffroy, — 

 \\'liicb Linnaeus regarded only as a first division of his genns Dyfisciis, but the anatomy of the two 

 grotips differs materially : tlie digestive eanal of the Hydrojthili, in its great length and texture, having 

 much analogy wilh that of tlie Lamellicorncs, aiiin-oaeliing the carnivorous tribes only in its 

 biliary vessels. 



Some of these have the body either oval, oblong, and depressed, or long and narrow, with the thorax rnngh and 

 narrowed behind ; the legs slender ; the tarsi filiform, but slightly ciliated ; the an tenure (always 9-jointed) teimi- 

 uating in an ohconical and nearly sniid eUib. These Palpicorne^ are all \ery small; they swim but Utile and 

 badly, inhabiting stagTiant \Mitcr, \\hieli they occasionally quit iri wArv to hide themselves in the earth ur Linder 

 stones. They compose the family Ilelophorhh-a of Leaeli, corresponding with the Fabrician genus Eloj'homs. 



i^/i^/'/^ori^-v, Fab,, having the body oval, thorax transverse, and eyes slightly elevated ; and 



Hj/droc/iui-, Germ., having the body long and narrow, the thorax oblong, and the eyes iinuninent {II. clomjatiis, 

 Fabr.), iiave the maxillary paljii terminated by an oval joint ; whilst Iti 



Ochlhchiiis, Leach, the maxillary jialpi are terminated, liy a more slerjder, ^Imrt, and conical joint, and the 

 thorax is nearly semlorbicular. IL /"hjnurus, Fabr. ; Ilfidra-na npitrin, I,atr. 



Hi/dnena, Kug"., has the inaxlll.'u-y [ial|ii much longer than the heiul and anteiina\ with the tei-minal joint larger 

 than the preceding, fn.siiorni, and iiointed at the tip. They ha\e the aspect of *.)chtliebius. E. inniiniu.s.ynh. ; 

 Hi/drwna ripnrlii, Kiigid. 



The other Hyilritidiiliens ha\'e the body (i\nid or sniihemispherical, and generally convex, with the thorax much 

 broader than long, the tibiae and tarsi ge-ni'i ally \Mtli long hairs. They compose the fAiuily Hi/drop/ii/idea of 

 Leach, or the genus IJi/dyop/i/hi.s, Fabr. 



Sperchcus, Fabr., has only six jennts in tlie aiitrnnit.', and the ch'ix-ns is notched. >S'. fiHnrt/iiu'fiis, Fubr. [a very 

 rare British species]. 



Glof-'iri'i, Latr., has the body nearly spherical, laterally compressed, and capable of being rulled into a ball like 

 Agatlndnini. Its antennaiappear to be only S-jointed, the fifth being dilated internally into a spine, the terniinnl 

 joints forming a very elongated, nearly cylindrical club, jioin led at the tip ; the el y Ira entirel\- embrace the abdo- 

 men, the four posterior tibiie having a brush of long hairs at the tip. The only species, (1. Lvacliii, \^ small and 

 exotic: I believe it to be from South America. 



All the remaining llydrophiliens have nine joints in the anteniur, ^vith the club o\'al ov ovuid, and the body nut 

 contractile into a ball. 



JTi/dfop/ii/KS, GeolL, comprises the largest species iii the tribe, witli tin? twn intermediate joints of the club of 

 the antennae obtuse at one end, and elongated, arched, and pointed at the other; the first joint of the clidj is 



