Antennæ straight;

Tarsi with a single unguis;

Second ventral segment elongated; last joint of antennæ very large.

TRIMIUM.

EUPLECTUS.

Second ventral segment not longer than the third. Tarsi with two equal ungues.

FARONUS.

The last genus is represented by F. Tolulæ in the southern Atlantic States, by F. Isabellæ in California, and by F. parviceps (Euplectus parviceps Mäklin) in Russian America. Trimium has been found in Russian America. The other genera are not represented near the Pacific coast.

FAM. X.-STAPHYLINIDAE.

Mentum quadrate, usually trapezoidal, the anterior part separate; ligula rarely corneous, usually membranous or coriaceous; paraglossæ usually distinct; palpi usually 3-jointed, rarely (in certain Aleocharini) with four, two, or even one joint.

Maxilla with two lobes, usually ciliate; palpi 4-jointed, except in Aleochara, where there are five joints.

Antennæ variable in insertion and form, 11-jointed, rarely 10-jointed.

Eyes usually finely granulated.

Prothorax with the side pieces not separate, prosternum variable in form, coxal cavities usually open behind.

Mesosternum short, side pieces large, epimera distinct. Metasternum moderately large, side pieces narrow, epimera distinct.

Elytra truncate, leaving a great part of the abdomen exposed, except in certain Omalini; wings, when present, folded under the elytra.

Abdomen with seven or eight visible segments, freely movable, and entirely corneous both above and beneath.

Legs variable in length and form; anterior coxæ usually large, conical, prominent, and contiguous, rarely (Piestida) rounded, not prominent, or (Micropeplida) transverse, not prominent; middle coxæ conical, oblique, not prominent, sometimes contiguous, sometimes distant; hind coxæ variable in form, contiguous, except in Micropeplidæ, where they are small, rounded, and distant.

Tarsi usually 5-jointed, rarely 4-jointed, and in Micrope. plide and certain Oxytelini 3-jointed; in many genera of

Aleocharini the anterior tarsi are 4-jointed, while the middle and hind tarsi have five joints.

This family embraces a very large number of species, mostly of small size, and in many parts of the body shows a very great range of variation. Genera with short elytra occur in several families of Coleoptera, but in no other are they associated with an entirely corneous abdomen having seven or eight visible segments.

I have separated the family into the same divisions as those adopted by Kraatz in the second volume of the Insecten Deutschlands, but I am not in accord with him in considering them all as of equal value in classification. The form of the anterior coxæ seems to me of greater significance than the other characters used in separating the different groups which have been previously called tribes, and I have made the primary division on the form of those organs into sub-families.

The prothoracic breathing-pores (stigmata) are visible in certain tribes (Aleocharini, Tachyporini, Staphylinini), but invisible in the rest of the family. This character is sometimes difficult to perceive; but I have not been able to follow the example of Duval, in excluding it from a primary place in the synoptic table of tribes. I would divide the family into three sub-families:Anterior coxæ prominent; anterior coxal cavities open behind.

STAPHYLINIDÆ.

Anterior coxæ not prominent; anterior coxal cavities entire ;
Anterior coxæ globose, posterior contiguous.
Anterior coxæ transverse, posterior distant.

PIESTIDE. MICROPEPLIDÆ.

Sub-Family I.-STAPHYLINIDAE (genuini).

This sub-family contains the great bulk of the species, and is much less homogeneous than the other two; the tribes composing it are as follows:

:

A. Prothoracic stigmata visible; insertion of the antennæ

Upon the front, at the internal margin of the eyes. I. ALEOCHARINI.
Under the sides of the front, behind the mandibles. II. TACHYPORINI.
At the anterior margin of the front, inside of the mandibles.
III. STAPHYLININI.

B. Prothoracic stigmata not visible, covered by the sides of the pronotum ;

Posterior coxæ conical, anterior coxæ large.
Posterior coxæ conical, anterior coxæ small.

IV. PÆDERINI.

V. STENINI.

Posterior coxæ transverse;

Anterior coxæ large, antennæ geniculate.

VI. OXYTELINI.

Anterior coxæ large, antennæ straight, ocelli two. VII. OMALINI.
Anterior coxæ transverse, not very prominent. VIII. PROTEININI.
Anterior coxæ large, antennæ straight, ocelli none.

IX. PHLOCHARINI.

Tribe I.-ALEOCHARINI.

The prothoracic stigmata in this tribe are not covered by the inflexed portion of the pronotum; but, without reference to this character, the insertion of the antennæ upon the front will distinguish the genera from those of all other tribes except the first group of Stenini, and these will be readily known by the small anterior coxæ.

Groups are indicated by the following characters :—

Internal lobe of the maxillæ membranous internally, and ciliate;

Eyes not prominent; third joint of maxillary palpi moderately elongated. ALEOCHARE.

Eyes prominent; third joint of maxillary palpi thickened. GYROPHÆNÆ, Internal lobe of the maxillæ elongated, entirely corneous, hooked at the tip, and serrate internally. GYMNUSE.

Group I.-Aleocharæ.

In this group the interior lobe of the maxillæ has the internal margin membranous and ciliate; the maxillary palpi are moderate in length, with the second and third joints moderately elongated, the fourth small, subulate, distinct, and in Aleochara with an additional very small fifth joint. The eyes are never very convex.

The genera of this group are very numerous, and frequently cannot be distinguished without the most close examination, or even dissection; it is consequently impossible, within the limits of a work like the present, to give such characters as will enable the student to recognize them with certainty. Those who are sufficiently advanced to study this group must, therefore, refer to the works of Erichson, Duval, and Kraatz for full information. Several of the genera recently established by Kraatz will probably be found represented in our fauna; but I have confined myself in the table to those actually known to me as occurring.

A. Anterior tarsi 4-jointed; middle and hind tarsi 5-jointed;

Head constricted behind into a narrow neck; first joint of hind tarsi elongated (thorax cordate, usually deeply channelled.) FALAGRIA.

Head not constricted into a narrow neck;

A. Joints of hind tarsi equal, or slightly decreasing in length;
Anterior and middle tibiæ strongly spinous externally.

Tibiæ not spinous;

PHYTOSUS.

Labial palpi 3-jointed;

Ligula long, slender, bifid at the extremity; joints of hind tarsi 1-4 equal.

HOPLANDRIA.

Ligula short, bifid; joints of hind tarsi 1-4 decreasing in length. HOMALOTA. Labial palpi very long, two-jointed; joints of hind tarsi 1—4 equal. STENUSA. B. Hind tarsi with the first joint decidedly longer than the second; a. Maxilla with inner lobe ciliate internally, with small spines; Labial palpi short, 2-jointed.

Labial palpi 3-jointed, joints quite distinct;

PLACUSA.

TACHYUSA.

Antennæ slender; abdomen narrowed in front; ligula short,
bifid; labial palpi with the first joint longer, second and
third equal.
Antennæ thick; ligula long, bifid at the tip; labial palpi
with the second joint shorter.
BOLITOCHARA.
Antennæ thick; ligula elongate, narrow, entire at tip;

labial palpi with the first joint shorter and wider than
the second.
PHILOTERMES.

b. Maxilla with the inner lobe ciliate, with hairs; at the apex with some corneous hooks;

Hind angles of thorax indistinct; abdomen of the usual form.

MYRMEDONIA.

Hind angles of thorax distinct; sides of thorax and abdomen widely reflexed, the latter with tufts of hair on the sides above.

B. All the tarsi 5-jointed;

Palpi with a small additional terminal joint.

Maxillary palpi 4-jointed, labial 3-jointed;

ATIMELES.

ALEOCHARA.

Head not narrowed behind; first joint of hind tarsi distinctly elongated.*

OXYPODA.

Head narrowed behind; first joint of hind tarsi scarcely elongated.
PHLOOPORA.

The species of Homolota are very numerous; the other genera are moderate in size, or represented only by single species.

Group II.-Gyrophænæ.

The species of this group are small, of an oval form, much

*Here belongs the genus Myrmecochara Kraatz (Linn. Ent., xi. 40), but from the description I am unable to discover any distinctive character between it and Oxypoda.

broader than those of the previous group, and are easily distinguished by the prominent eyes, and by the third joint of the maxillary palpi being thickened. They live exclusively in fungi, and are gregarious; they are remarkable for the smooth shining surface, almost destitute of hairs or punctures. The anterior tarsi are 4-jointed, and the middle and posterior ones 5-jointed; the first joint of the hind tarsi is elongated; the thorax is distinctly margined. The labial palpi have but two joints.

Our species belong to Gyrophæna, which is distinguished from the other genera of the group by the entire ligula, and the very short second joint of the labial palpi.

Group III.-Gymnusæ.

In this group the lobes of the maxillæ are long and slender, the inner one is entirely corneous, serrate internally, and hooked at the apex. The maxillary palpi have the second and third joints very long, and the fourth not very distinct. The head is deflexed, pointed in front; the antennæ slender; the thorax and elytra broad, and the abdomen strongly but gradually narrowed behind, so that a form is assumed approaching that of some members of the next tribe.

Labial palpi setaceous, with two indistinct joints; anterior tarsi 4-jointed, posterior ones 5-jointed; ligula short, entire. MYLLENA. Labial palpi large, 3-jointed, last joint very small; tarsi 3-jointed; ligula large, bifid; lobes nearly as long as the palpi.

DINOPSIS.

Thus far species have occurred only in the Atlantic States; they are but three in number (one Myllena, two Dinopsis), and are found in very wet places.

Tribe II.-TACHYPORINI.

The prothoracic spiracles are visible; the anterior coxæ are large, conical, and prominent, with the trochanters very distinct. The antennæ are inserted under the lateral margin of the front.

The species are usually convex, with the thorax always ample, arched, and highly polished, and the abdomen conical, sometimes very short. They are found partly in fungi, partly under bark. Our genera are easily distinguished by the following table :A. Antennæ 10-jointed, tarsi 4-jointed (body very small, convex).

HYPOCYPTUS.