COLEOPTERA. 543 



Pavssiis proper, has only two joints to the antcnnse, the second very lai'jjc and compressed. 

 llylotorns, Dalm., composed of a sin^^le species apparently with ocellijand with the antenna scarcely lonsfer than 

 tliti head, and 2-jointed. 

 CeraptemSy Swed., lias the antennae 10-jointed and perl'oliated. 



2. Those which have only 10-jointed antenna;, and the maxillary palpi are not narrowed to the tips, 

 but are of equal thickness tliroughout, or thicker at the tips ; the joints of the tarsi are always entire. 

 They are divisible into two principal genera; those with the three terminal joints forming a perfoliated 

 mass compose that of — 



BosTRicHUs, Geolfr. 



Bostrichus proper, has tliebody cylindrical, the thorax forminf? a kind of hood over the head. The species are 

 found in old wood and timlier. [B. capuc'uius, a rare British species.] 



Psoa, Fabr., has the body narrower, and thorax flat. 



CiSy Latr., has the body oval, depressed, or but little elevated ; the last joint of the tarsi much longer than the 

 others; the head of the males often horned. [Many minute species, found in fungi.] 



Sphhidus, scarcely appears to me to differ from the last, 



Nemosoma, Desmar., has the body Ions', linear, and the mandibles robust andexserted. [N. elongata, a singular 

 small and very rare British species, found under the bark of old palings.] 



The second principal genus, — 



MON'OTOMA, — 



Has the cUib (or tenth joint) of the antennas solid, and button-shaped ; the body is elongated, with the front of the 

 head narrowed mto an obtuse muzzle ; the palpi ai'e very small, and, as well as the mandibles, not prominent. 



tSi/nchita, Helw., has not the fiont of the head prolonged, and the two basal joints of the antenna.^ are alike. 



Cen/loii, Latr., has the front of the head produced into an obtuse triau^le ; the tirst joint of the antennje much 

 longer than the second ; the body nearly oval or parallellipiped,and the elytra not truncate behind. [C. hislcrohhsy 

 a small species found under the damp bark of trees.] 



Rhi/zophaijus, Herbst., differs from Cerylon in its narrow elongated form and elytra truncate at the tip ; the 

 tarsi appear to me pentamerons. 



Monotoma, Herbst., differs from all the preceding in having the head as large as, and separated from, the thorax, 

 by a narrowed part. Cerylon ),icipes [and other small species, of which Aube has given a monograph in the 

 Annales de Soc. Enfomol. de France]. 



3. Those which have eleven cUstinct joints to the aiitennEC ; the palpi filiform, or thickened at the, 

 tips in some, or slender at the tips in others, the tarsal joints are entire. 



In some of these the club of the antenna; consists only of two joints. These form the genus 



Lyctus. 



Lyctus proper, Fab., has the mandibles and basal joints of the antenna; exposed. 



Dlodesma, Megerle, has the basal joint of the antenna hidden by the side of the head : the body oval, oblong-, 

 convex. Z>. subterraiiea. 



li/toma, Herbst., differs in having the body long, narrow, depressed. [B. crenata, a small British species, found 

 under the bark of trees.] 



In the others the three or four terminal joints of the antenna: form the club, the last being larger than the pre- 

 ceding joints. 



In some the mandibles are concealed or scarcely visible ; these are the genus 



Mycetophagus,— 



CoUidinm, Fabr., has the antenna scarcely longer than the head, and inserted beneath the advanced sides of the 

 head, and terminated by a perfoliated mass. 



MvcetopJiagiis proper, has the antennie at least as long as the thorax, the body oval, thorax transverse, and the 

 club of the antennffi commencing at the sixth or seventh joint. [J/, quadripmtulatus, and several other species of 

 small size, found under old stumps of trees, bark, &c.] 



Triphtilhis, iMeg., has the club of the antennae shorter, and formed suddenly by the last three joints, the lastbeing 



globular. 



ilA'/'i/.r, Latr., has the maxillary palpi exserted, and terminated by an enlarged joint, of a reversed triangular 

 furm. [M. rutjosusy Latr., New Holland.] 



Da^ucerus, Brongn., has 3-jointed tarsi ; the antennae have all the intermediate joints capillary, and very setose ; 

 the abdomen is nearly globular. 



Latridim, Herbst. has the palpi very short, pointed at tip; the head and thorax narrower than the abdomen, 

 which is subquadrate, or subovate ; the basal joint of the antennae is very thick. [L. porcatus, and other species 

 of minute insects, having domestic habits.] 



SilvanitSy has the body nearly linear, the thorax longer than broad, and as broad as the base of the elytra ; the 

 palpi nearly filiform. [T. dentatus, a small Hat insect, often found floating in tea and coffee, introduced with the 



sugar.] 



In others the mandibles are entirely exposed, and large ; the body often narrowed and depressed, 'lliese inseO.s 

 compose the genus— 



