joint acuminate, not shorter than the penultimate joint. The mentum is toothed; the third joint, and even the second joint, of the antennæ is pubescent. The head has the frontal impressions long and deep, curved behind the eyes, forming a slight posterior constriction. The anterior tibiæ are either linear (Anophthalmus) or slightly dilated, not spinous at the tip. The anterior tarsi of the male have two somewhat obliquely dilated joints, furnished beneath with squamiform papillæ. The epimera of the mesothorax are short, and somewhat triangular. The elytra are rounded at the apex, with the eighth stria anteriorly confluent with the margin, and most frequently interrupted at the middle.

Two genera are represented in our fauna; both have the first stria of the elytra recurved at the apex.

Eyes wanting; anterior tibiæ linear.

Eyes large; anterior tibiæ slightly thickened.

ANOPHTHALMUS.

TRECHUS.

Anophthalmus Tellkampfii is found in the Mammoth Cave, Kentucky; other species will be found in our other caves, when scientific zeal shall cause them to be properly explored. Trechus is found on both sides of the continent, but only in northern regions. The European T. rubens has recently been found by Mr. H. Ulke in Nova Scotia. Trechus includes Epaphius.

I formerly placed Tachys in this tribe; by the definitions here. given it belongs more properly to the next; but with the European genus Perileptus Schaum there is a very close osculation between the two tribes.

Tribe XVI.-BEMBIDIINI.

The ligula has but two bristles at the apex, which is free for a very short distance; the paraglossæ are distinct, scarcely longer than the ligula; the penultimate joint of the palpi is obconical, and the last joint much narrower and shorter, so as to be subulate. The mentum is strongly toothed, and the tooth is usually emarginate. The two basal joints of the antennæ are glabrous, the third is pubescent. The form of the head and frontal impressions are variable. The anterior tibiæ are slightly spinous at tip, either squarely truncate as usual, or slightly dilated and obliquely truncate, with the outer angle a little prominent. The anterior tarsi of the male are usually somewhat obliquely dilated in the first and second joints, the first being much larger than the second, but in

Anillus, Pericompsus, and certain Tachys the tarsi of the male are not at all dilated. The epimera of the mesothorax are more or less triangular. The elytra are entire, and rounded at tip, with the eighth stria usually confluent anteriorly, or nearly so, with the margin sometimes widely interrupted, but usually entire.

Like the other genera of Carabidæ containing very numerous species, Bembidium consists of groups of species differing greatly in form, and even in the structure of the parts of the mouth; but the characters being evanescent, cannot be used for the definition of genera.

Our genera are as follows:

Eyes wanting.

Eyes small, flat.

Eyes large or moderate, convex;

ANILLUS. LYMNEUM.

BEMBIDIUM.

Anterior tibiæ not dilated at the apex; elytra with scutellar stria; sutural stria not recurved at the apex. Anterior tibiæ slightly dilated and obliquely truncate at the apex; elytra without scutellar stria; sutural striæ recurved at the apex; Elytra with the eighth stria interrupted or less deep at the middle.

Elytra with eighth stria very deep.

TACHYS. PERICOMPSUS.

Of Anillus and Lymnæum but single Californian species have yet been found; the other genera are widely diffused. Blemus anescens Lec. must be placed in Tachys, the smaller proportional size of the third joint of the antennæ not being sufficient for generic separation.

FAM. III.-AMPHIZOIDAE.

Mentum deeply emarginate, with a medial tooth; lobes obtusely rounded; ligula large, quadrate, corneous; gular

suture none.

Maxilla with the outer lobe narrow, glabrous, palpiform, but not biarticulate; the inner lobe curved, acute at the apex, sparsely ciliate, with spines internally.

Antennæ inserted under the front, behind the base of the mandibles; entirely glabrous, polished.

Prothorax with the epimera and episterna moderately distinct; prosternum produced behind over the mesosternum. Metasternum truncate behind, not reaching the abdomen.

Abdomen with six ventral segments, the anterior three

connate.

Legs slender, formed for running; anterior and middle coxæ small; globular cavities of the former not closed; posterior dilated internally, contiguous at the inner margin, extending also to the margin of the body, separating the side pieces of the metasternum from the first ventral segment.

Notwithstanding the searching analysis of the characters of Amphizoa insolens, made by Dr. Schaum in his Insecten Deutschlands, I must differ with my eminent friend regarding the interpretation of the characters, and still regard it as representing a distinct family, and not as a very aberrant Carabide. It is true that the characters it shows, with the exception of the metasternum truncate behind, individually are found in various anomalous Carabidæ, but the concentration of all of them in one object, with the addition of yet another, entirely unknown otherwise in the series of land carnivorous beetles, surely constitutes sufficient reason for regarding this single species as the representative of a distinct type, equal in value to the families which precede or those which follow.

In addition to the characters given above, I would mention: the head is broad, obtuse; the eyes very small; the labrum very transverse, sinuate in front; the palpi short, cylindrical; the side suture of the under surface of the prothorax is distinct, the others are nearly obliterated; the prosternum is broadly produced behind the coxa, and obtusely rounded at tip; the coxæ are not entirely enclosed, but are protected behind by the mesosternum. The latter is deeply concave behind, perpendicular in front, and is almost covered by the prosternum when the thorax is deflexed. The side pieces are diagonally divided, and the epimera reach the coxa, which are small and round. The metasternum is prolonged and obtusely rounded between the middle coxæ, transversely truncate behind; the side pieces are triangular, without visible epimera; the posterior coxæ are large, flat, rounded behind, extending to the margin of the body, internally contiguous for a space nearly equal to the length of the metasternum, with a quadrate internal dilatation for the insertion of the legs, as in Carabidæ.

The legs are slender, rough with granulated points; the anterior tibiæ are not in the least degree sulcate internally, and have two small terminal spurs; the tarsi are glabrous, the joints rounded beneath; the claws simple. The elytra are twice as broad as the

thorax, connate, rounded, not convex, with nine dorsal furrows, and no marginal one; the apex is slightly sinuate.

The surface is rough, without lustre, and moderately coarsely punctured.

This very singular insect is found in northern California, probably near the Sierra Nevada; of its habits nothing is known.

FAM. IV.-DYTISCIDAE.

Mentum deeply emarginate, broadly toothed in the middle; lobes somewhat acute; sides rounded, converging in front; gular suture distinct; ligula large, quadrate, corneous.

Maxilla with the outer lobe biarticulate, the inner curved, acute at the apex, ciliate internally.

Eyes rounded, never emarginate.

Antennæ inserted under the front, behind the base of the mandibles, glabrous, polished, usually filiform, 11-jointed (rarely 10-jointed).

Prothorax with the epimera and episterna distinct; prosternum compressed, produced behind and fitting into a cleft or emargination of the metasternum; anterior coxæ protected behind by the mesosternum, subconical.

Metasternum short, pointed behind, but very closely connate with the posterior coxæ.

Posterior coxæ very large, usually oblique, contiguous at the inner margin, reaching the side of the body, entirely cutting off the ventral segments from the metathorax; internally with a small dilatation for the insertion of the legs, or a broad plate (Haliplini) extending over their whole surface, and also covering the greater part of the abdomen.

Abdomen with six ventral segments, the three anterior ones connate, the sixth rounded at tip, usually permitting the seventh internal but corneous one to be slightly visible.

Legs ciliate with long hairs, posterior usually compressed, elongated, formed for swimming; tarsi 5-jointed, the fourth joint of the anterior and middle tarsi sometimes obsolete.

In this family are contained aquatic carnivorous insects, having, as will be seen by the above characters, a close relationship to Carabidae, and in fact only differing by the form of the posterior coxæ, and the natatorial legs. The particular portion of the Carabida which approaches most nearly these insects is found in the

first sub-family. In common with that series, the Dytiscidæ have the side pieces of the mesosternum diagonally divided, with the epimera reaching the coxæ; the side pieces of the metasternum are narrow, without visible epimera. The middle portion of the mesosternum is entirely covered; on separating the prothorax, it is found to be deeply sulcate for the reception of the prolongation of the prosternum, which thus firmly unites the different parts of the body, so as to give the stability necessary for rapid motion through the water.

The body is rounded, sometimes elongated, usually elliptical, rarely very convex. The species are more numerous in the northern parts of the country; they are all winged, and the elytra are always marked with three discoidal, irregular rows of punctures; rarely the elytra are sulcate (Copelatus, females of certain Dytiscus), frequently punctured, sometimes sculptured with transverse lines (certain Colymbetes).

The genera represented in our country form two sub-families, so distinct that they might with much propriety be considered separate families.

Sub-Family I.-HALIPLIDAE.

Antennæ 10-jointed; abdomen covered with large plates of the posterior coxæ, which are small and transverse; metasternum almost truncate behind, scarcely emarginate in front; legs scarcely natatorial.

This series consists of a single group, containing but two genera, Haliplus and Cnemidotus, of small size; the body is very convex, somewhat acute before and behind, yellow shining, spotted with black or gray. The elytra are covered with rows of punctures; in Haliplus there are nine and a marginal series, in Cnemidotus there are eleven or twelve. The scutellum is not visible. The insects of this sub-family swim but feebly, and with little activity. Palpi subulate.

Palpi filiform.

HALIPLUS. CNEMIDOTUS.

Sub-Family II.-DYTISCIDAE (genuini).

Antennæ 11-jointed; posterior coxæ without plates, very large (except in the European genus Pelobius); legs very natatorial (except in the same genus).