COLEOPTERA. \ 99 
pletely exposed. The body is narrow, elongated, and almost linear ; 
the eyes are large and the thorax is elongated. 
Lyctus, Fab. * 
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 
Diopesma, Meq., Dej., 
The antenne are as long as the thorax, the body is a convex oblong 
oval, the thorax is almost semiorbicular, and the abdomen nearly 
oval f. 
Brroma, Herbst., Gyll—tbLycrus, Fab. 
Where the antenne are shorter than the thorax; the body is long, 
na1row, depressed, and almost a parallelopiped ; the thorax is square f. 
In the other Xylophagi with antennze composed of eleven joints, 
the three or four last form the club, or the last is alone larger than 
the preceding ones. ‘hey are subdivided thus: 
Sometimes the mandibles are covered or project but little, as in- 
Mycetornacus, Fab. 
Here the antenne, hardly longer than the head, are inserted under 
the projecting margin of the head, and terminated abruptly by a tri- 
articulated, perfoliate club. 
Cotypium, Fab. 
Their body is linear, and the head very 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 antenne are larger 
than the following ones, which, to the eighth inclusively, are very 
short and transversal §. 
There the antenne 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 antenne 
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. ~ 
Myceteruacus, fab.—Triroma, Geoff. 
In Mycetophagus proper, the club of the antennz 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. 
+ Diodesma subterranea, Dej., Catal., p. 67. 
t See Lat., Gyllenhall. 
§ See Lat., Fab., Dej. 
|| See Lat., Gener. Crust. et Insect., III, p. 9. first division of the Mycetophagi ; 
and Gyll,, Insect, Suec., I, iii, 387, and IV. 630. 
