CLASSIFICATION

OF THE

COLEOPTERA OF NORTH AMERICA.

FAM. I.-CICINDELIDAE.

MENTUM deeply emarginate; ligula small, concealed; base of labial palpi free.

Maxilla with the outer lobe biarticulate, the inner usually terminated by an articulated hook.

Antennæ inserted on the front, above the base of the mandibles.

Prothorax with the epimera and episterna distinct. Metasternum pointed behind, reaching the abdomen. Abdomen with the three anterior segments connate; 6-articulated in the female, usually 7-articulated in the male. Legs slender, formed for running; posterior coxæ dilated internally, not reaching the margin of the body; tarsi 5-jointed.

The species composing this family are the most predaceous of Coleoptera, and in some of them activity as well as brilliancy of coloring is carried to its greatest perfection. The genera found in the United States are all terrestrial, but within the tropics are many which alight only on leaves of trees. More full descriptions of the habits will be given below, under the particular groups.

The head is large; the mandibles long and sharply toothed; the maxillæ have two lobes; the interior is armed with spines on its inner margin, and in our genera is terminated by an articulated hook, which is wanting in some foreign genera; the mentum is large, deeply emarginate with the lateral angles acute, armed in the middle with a large acute tooth, and is separated from the gula by a distinct suture; the ligula is small, hidden under the mentum tooth; the base of the labial palpi is free and prominent, appearing like a separate joint.

The antennæ are inserted upon the front, above the mandibles; they are always 11-jointed, with the four inferior joints glabrous and polished, the others pubescent; they are usually filiform, rarely thickened externally.

The thorax is usually cordate, sometimes cylindrical, rarely quadrate; the dorsal surface is marked by an anterior and posterior transverse impression, and a dorsal line connecting the two transverse impressions; the lateral margin is not well defined, as in most of the genera of the next family; the prosternum is narrow, not produced behind; the episterna and epimera are distinctly defined by sutures, and the anterior coxæ are globular, with the cotyloid cavities entire.

The mesosternum is obliquely declivous, deeply emarginate behind; the epimera and episterna are sometimes connate, without suture, and sometimes distinct; in the latter case the suture runs diagonally, and the epimera extend to the middle coxæ, which are globular.

The metasternum is pointed in front and behind, reaching the middle of the second ventral segment; the epimera are large in the winged species, small in the apterous ones; the episterna are small, and frequently indistinct. The posterior coxæ are triangular, dilated and prominent internally, concave behind for the motion of the thighs; they do not extend to the margin of the body, but are inclosed by the side pieces of the metathorax, and the first ventral segment.

The elytra cover the body, and are rounded at the tip; sometimes they are connate, and sometimes (as in Amblychila) embrace widely the flanks of the abdomen; the wings are usually well developed, sometimes wanting.

The legs are slender, usually long; the tibiæ have two distinct terminal spurs; the tarsi in our genera are filiform, the first three joints of the anterior ones of the male usually dilated, and densely clothed with hair beneath. The claws are acute, and simple.

The abdomen is composed in the female of six ventral segments; in the male the sixth segment is usually deeply emarginate, and a small seventh segment is thus seen, but in Amblychila the abdomen is alike in both sexes; the three anterior segments are closely connate, the first is visible only on the sides, the second is acute in the middle, and reaches the point of the metasternum; the others are movable. The dorsal segments, as first observed by Dr. Schaum,

are eight in the male and seven in the female, the seventh in the latter sex being elongated so as to conceal the eighth.

This family is divided by Lacordaire into five tribes, of which but three are found within the limits of the United States, and are distinguished in the following manner:

A. Third joint of maxillary palpi longer than the fourth.
First joint of labial palpi very short.
First joint of labial palpi elongated.

MANTICORINI. MEGACEPHALINI. CICINDELINI.

B. Third joint of maxillary palpi shorter than the fourth.

Tribe I.-MANTICORINI.

The species of this tribe are apterous, with the elytra connate; the eyes are small, and in this respect they differ from all other members of the family; the first joint of the labial palpi is very short, and hardly extends beyond the emargination of the mentum.

These insects are probably crepuscular or nocturnal in their habits. I am informed by Dr. Wm. A. Hammond, that specimens of Amblychila were found by him running about in the early morning of cloudy days. The only specimens of Omus found by me were drowned in a rain-pool near San Francisco. In Amblychila the usual differences between the sexes fail; the tarsi of the male are not dilated, and the abdomen has only six ventral segments. In Omus the anterior tarsi of the male are widely dilated, and the 7th ventral segment is distinct.

Two genera of this tribe are found in our country, and both are peculiar to it. Amblychila, having wide epipleuræ, occurs in Kansas, New Mexico, and probably in California. (1 species.) Omus, having narrow epipleuræ, is found in California, Oregon, and Washington Territory. (3 species.)

Tribe II.-MEGACEPHALINI.

The native species of this tribe are but two in number, and belong to the genus Tetracha. T. virginica is crepuscular in its habits; T. carolina extends from the Atlantic to the Pacific coast.

Tribe III.-CICINDELINI.

Of this tribe the species are very numerous. Those of our fauna belong, with one exception, to Cicindela, and many of them are seen on roads exposed to the sun, flying actively on the least alarm, and again alighting at the distance of a few paces. The

species are more numerous in the temperate and warm regions of the country, and gradually disappear towards the north, until in the latitude of Lake Winnipeg but two or three species remain.* Our species all belong to the genus Cicindela.t

The larvae of Cicindela, like the perfect insects, live in holes, which they excavate with their jaws and feet, in sandy localities, using, as stated by Westwood, their broad head for bringing the particles to the surface. They are easily procured in spring by placing a fine straw down the hole, when the larva will gradually push it out, and rising to the surface, may be captured. They are whitish grubs, with a large, flat, metallic-colored head, with long toothed mandibles; the prothoracic segment is protected above by a large, lunate, corneous scute; the ninth segment has two dorsal hooks; the tarsi are terminated by two claws. They lie in wait for prey at the mouth of the burrow, the head and thorax closing the opening, and seize with the long mandibles any insect which approaches within reach.

FAM. II.-CARABIDAE.

Mentum deeply emarginate; ligula more or less prominent, usually furnished with paraglossæ.

Maxilla with the outer lobe palpiform, usually biarticulate, the inner usually curved, acute, ciliate with spines.

Antennæ inserted behind the base of the mandibles, under a frontal ridge.

Prothorax with the epimera and episterna usually distinct.

* For a synopsis of the native species of Cicindela, see Transactions of the American Philosophical Society, vol. XI.

While this sheet is passing through the press, Mr. Ulke has kindly loaned me a female specimen of Dromochorus Pilatei Guérin, which he has recently received. It has not the third joint of the labial palpi any thicker than in ordinary Cicindelæ, but differs, however, by the wings being entirely wanting. In several species of Cicindela, the wings are very feeble, and in that case the humeral angles of the elytra are not distinct, so that the form of Dromica is assumed. I am disposed, therefore, to consider D. Pilatei as constituting merely an aberrant group of Cicindela, in the neighborhood of C. dromicoides, and our own C. celeripes. It is a black insect, about half an inch long, without lustre. The eyes are moderately large, and the front is scarcely concave, with but few wrinkles. The elytra are convex, oval, narrowed in front, and covered with not very deep bluish punctures; there is no sutural spine, and the apex is entirely without serrature. The tarsi are more pubescent than in other species. The labrum is armed with three acute teeth. It is found in Texas.