The maxillæ are not seen in my specimens. The antennæ are 11-jointed, with 3-jointed club; antennal grooves short; the front truncate, sides widely dilated.

The anterior coxæ are transverse, but prominent and contiguous; the coxal cavities are closed behind. The posterior coxæ are transverse, but prominent internally, and concave behind. The tibial spurs are obsolete. The joints 1-4 of the tarsi are very short and equal, hairy beneath; the last joint is very long, with moderate-sized simple claws. The fifth ventral segment is rounded behind, but the sixth projects slightly.

FAM. XVIII.-COLYDIIDAE.

Mentum subquadrate, rarely covering the base of the maxillæ; ligula corneous; palpi 3-jointed, short.

Maxilla with two lobes; palpi short, 4-jointed.

Antennæ inserted under the margin of the front, 10- or 11-jointed, rarely 8-jointed, sometimes gradually thickened, usually terminated by a small sudden club.

Prothorax with the side pieces not distinct; anterior coxal cavities almost always closed behind, sometimes distant, sometimes confluent; prosternum scarcely ever prolonged behind the coxæ.

Mesosternum small, side pieces not attaining the coxæ. Metasternum large; side pieces long, narrow; epimera not

visible.

Elytra never truncate, always covering the abdomen.

Abdomen with five ventral segments, the three or four anterior ones more or less connate.

Anterior and middle coxæ small, globular, not prominent; posterior transverse, either distant or contiguous, not promi

nent.

Legs short; tibiæ not dilated; terminal spurs usually small, frequently indistinct; tarsi 4-jointed, not dilated; ungues simple.

. Small insects, usually of an elongate or cylindrical form, living under the bark of trees, in fungi, or in the earth. The small globular anterior and middle coxæ, and the 4-jointed simple tarsi, will enable them to be readily distinguished from any of the neighboring families.

Five tribes, established by Erichson, and all represented in our

Most of the species of this tribe are remarkable for being covered with asperities, usually bearing erect bristles; the form is sometimes elongate, but frequently oval, resembling Peltis. In our genera the first three tarsal joints are nearly equal, and the tibiæ have no terminal spurs, or only very small ones.

A. Tibiæ filiform, not spinous, without terminal spurs ;

a. Antennæ not retractile under the head, 11-jointed (body elongate, costate);

Antennæ thick, perfoliate; eyes very narrow, remote from the margin of the head.

Antennæ moderate; eyes round, lateral.

b. Antennæ received in grooves under the head;

ANCHOMMA.

RHAGODERA.

Prosternum not produced behind; antennæ with 2-jointed club;

antennal grooves short.

B. Tibiæ filiform, not spinous, with small terminal spurs ;

a. Antennæ 11-jointed, with 2-jointed club;

COXELUS.

Antennal grooves wanting; first and second joints of antennæ dis

C. Tibiæ slightly thickened, with small terminal spurs, and a few small spines at the extremity; antennæ 11-jointed, with 3-jointed club; (body costate) LASCONOTUS.

Tribe II.-COLYDIINI.

Species having a cylindrical, sometimes very slender, form; found under bark. The European genus Aglenus has no eyes, but in all of ours the eyes are distinct. The elytra are striate, rarely ribbed. The first joint of the tarsi is elongate in all of our

genera, except Oxylemus. in which also the anterior coxal cavities are open behind.

A. Frontal margin broad, covering the insertion of the antennæ ;
Club of antennæ 3-jointed; (thorax with impressed lines);

Anterior tibiæ with one spur enlarged, hooked; elytra finely or

scarcely striate.

Anterior tibiæ with small spurs; elytra ribbed.

Club of antennæ 2-jointed; body costate.

B. Frontal margin not dilated; base of antennæ exposed;

Anterior coxæ distant;

AULONIUM.

COLYDIUM.

EULACHUS.

Eyes flat; spurs of the tibiæ small, outer angle prolonged; (elytra

striate, body very elongate).

Anterior coxæ contiguous;

NEMATIDIUM

PLEURIDIUM.

First joint of tarsi long; club of antennæ with two distinct joints;
(elytra costate).
First joint of tarsi short; club of antennæ globular, composed of
two connate joints; elytra coarsely punctured in rows.

OXYLEMUS.

Tribe III.-BOTHRIDERINI.

In this tribe the posterior coxæ are widely separated, and the first ventral segment is elongated. The species are somewhat flattened, and the elytra are ribbed; the buccal cavity is deep, and the oral organs are retracted; the mentum is transverse and concave, and the inferior margin of the mandibles is dilated at the base; the eyes are not prominent; the antennæ are short, 11-jointed, with the club 2-jointed.

Two species of Bothrideres are known to me. The genus is distinguished by the anterior coxæ being very widely separated.

Tribe IV.-PYCNOMERINI.

Elongate, somewhat flattened species, covered with coarse punctures, having on the elytra rows of very large punctures. The palpi are cylindrical, and the posterior coxæ, as in the preceding tribe, are distant, but the ventral segments are equal in length.

Antennæ with eleven distinct joints, club 2-jointed.
Antennæ with ten apparent joints, club solid.

ENDECTUS. PYCNOMERUS.

Endectus contains Lyctus hæmatodes Fabr. and L. reflexus Say, previously enrolled in Pycnomerus, and one nondescript; of the latter genus but one species is known to me. They are all from the Atlantic States.

Tribe V.-CERYLINI.

Small, oblong or oval, flattened insects, having all the coxæ widely separated, the first ventral segment elongated, and the last joint of the palpi small and acicular, the penultimate thick; lobes of the maxillæ long and slender.

Antennæ 11-jointed; (body pubescent).
Antennæ 10-jointed; (body glabrous).

PHILOTHERMUS.

CERYLON.

FAM. XIX.-RHYSSODIDAE.

Mentum very large, quadrate, bisinuate in front, covering entirely the mouth beneath; palpi short, 3-jointed.

Maxilla with two small lobes; palpi short, 4-jointed. Antennæ inserted under the frontal margin, 11-jointed, joints nearly equal, rounded, the first larger, but also rounded. Prothorax beneath with the side pieces distinct, the suture running parallel with the lateral margin; coxal cavities closed behind, widely separated.

Mesosternum very short, side pieces diagonally divided, epimera reaching the coxæ.

Metasternum very large; side pieces very narrow, almost concealed by the elytra.

Elytra rounded at tip, covering the abdomen, with six or seven deep furrows, or rows of punctures; scutellum wanting. Abdomen with six ventral segments; the first visible only between the coxæ, broadly triangular; the three anterior ones closely connate.

Anterior coxæ small, globular, not prominent; middle coxæ globular, small; posterior coxæ small, subtriangular, prominent internally, all of them widely separated.

Legs short; anterior tibiæ somewhat dilated, terminated by two hooks, on the under surface sulcate towards the tip, subemarginate, and armed above the tip with a spine; middle and posterior tibiæ with an internal terminal spine, spurs distinct; tarsi 5-jointed, very slightly pubescent beneath; posterior trochanters prominent, oval.

Two genera, of singular form, found under bark, constitute this family, which in several of its characters resembles the Carabidæ, but yet not so as to belong to the same series. The antennæ are

composed of equal globular joints; the head is strongly constricted behind into a neck, and is sculptured with two deep grooves, converging behind; the thorax is long, has three entire grooves, and two short posterior broader ones (Clinidium), or three deep entire ones, and two finer lateral lines (Rhyssodes); the elytra are deeply grooved in Clinidium, coarsely striato-punctate in Rhyssodes.

Eyes lateral, rounded, distinctly granulated.

RHYSSODES.

Eyes superior, narrow, scarcely granulated (sometimes wanting?).

CLINIDIUM.

FAM. XX.-CUCUJIDAE.

Mentum small, subquadrate, usually transverse; ligula corneous, prominent; palpi short, 3-jointed.

Maxilla with two lobes; palpi 4-jointed.

Antennæ inserted at the margin of the front, 11-jointed, sometimes long and slender, sometimes with the outer joints slightly enlarged, the first joint usually elongated.

Prothorax with the side pieces not separate from the upper piece; coxal cavities separated by the prosternum, widely open behind, with a fissure externally leading to the episternal suture in the second and third sub-families, entirely closed in the first, fourth, and fifth.

Mesosternum moderate; epimera reaching the coxæ.

Metasternum large, quadrate; episterna long, narrow, co

vered.

Elytra rounded at tip and covering the abdomen, except in the fourth sub-family; usually flat, strongly margined; scutellum distinct.

Abdomen with five free ventral segments, equal in length. Anterior coxæ small, globular, not prominent; middle coxæ small, subtriangular, not prominent; posterior coxa nearly contiguous, transverse, slightly prominent.

Legs moderate; tibiæ slender, with two small terminal spurs; tarsi with the first joint usually small, sometimes 5jointed in both sexes; the posterior tarsi sometimes 4-jointed in the males.

The species which constitute this family are, with one exception (Narthecius), very depressed, and usually of an elongate form. They live under bark.