COLEOPTRRA. 99 



pletely exposed. The body is narrow, elongated, and almost linear; 

 the eyes are large and the thorax is elongated. 



Lyctus, Fah. * 



In Lyctus proper, the margin of the head covers the whole or 

 greater part of the first joint of the antennae. The mandibles are 

 not salient. In 



DioDEsMA, Meg., Dej., 



The antennfe arc as long as the thorax, the body is a convex oblong 

 oval, the thorax is almost semiorbicular, and the abdomen nearly 

 oval f . 



BiTOMA, Herbst., Gyll. — Lyctus, Fah. 



Where the antennre are shorter than the thorax ; the body is long, 

 narrow, depressed, and almost a parallelepiped : the thorax is square J. 



In the other Xylophagi with antennae composed of eleven joints, 

 the three or fovir last form the club, or the last is alone larger than 

 the preceding ones. They are subdivided thus : 



Sometimes the mandibles are covered or project but little, as in 



Mycetophagus, Fab. 



Here the antennae, hardly longer than the head, are inserted under 

 the projecting margin of the head, and terminated abruptly by a tri- 

 articulated, perfoliate club. 



CoLYDiujr, Fab. 



Their body is linear, and the head A'-ery obtuse before ; the thorax 

 is as wide as the abdomen, and forms a square more or less long; the 

 abdomen is elongated. The two first joints of the antennae are larger 

 than the following ones, which, to the eighth inclusively, are very 

 short and transversal §. 



There the antennae are at least as long as the thorax. 



The body is oval, the thorax transversal and widest posteriorly ; 

 the first and last joints of the tarsi are elongated, and the antennae 

 terminate in a perfoliate club, either oval or commencing near the 

 sixth or seventh joint, or abrupt, somewhat oval and formed of the 

 three last. 



They live in mushrooms or under the bark of trees. 



Mycetophagus, Fab. — Tritoma, Geoff. 



In Mycetophagus proper, the club of the antennae commences at 

 the sixth or seventh joint; the the last is almost ovoid ||. 



* See Lat., and Gyllenhall. The genus Lyctus of Fabricius is a mixture, 

 f Diodesma suhterranea, Dej., Catal., p. 67. 

 X See Lat., Gyllenhall. 

 § !:ee Lat., Fab., Dej. 



II See Lat., Gener. Crust, et Insect., Ill, p. 9. first divisioa of the Mycetophagi ; 

 and Gyll., Insect, Suec., I, iii, 3S7, and IV. 630. 



