alone represents this tribe in our fauna. It is an oval, convex, shining black insect, about a quarter of an inch long, with fine rows of punctures on the elytra.

The mandibles and labrum are corneous, prominent; antennæ 10-jointed, the club 3-jointed, the first joint hollowed and receiving the second; anterior coxæ conical, prominent; middle coxæ oblique, contiguous; epimera of the metathorax visible; ventral segments six, all but the last connate. Tarsi with a short bisetose onychium.

Tribe V.-GEOTRUPINI.

Insects of rounded convex form, some living in excrements, others found wandering about without visible means of support; the elytra strongly striate in nearly all; the thorax of the males, and more rarely the head, armed with horns or tubercles.

The mandibles and labrum corneous, prominent; antennæ 11jointed, club 3-jointed, variable in form; anterior coxæ prominent; middle coxæ more or less oblique, usually contiguous, but separated in Athyreus; epimera of the metathorax visible; ventral segments six, free; the elytra covering the pygidium; tarsi with a bisetose onychium.

With the exception of one species of Odontæus from California, our species are all found east of the Rocky Mountains.

This tribe contains but a single Californian species, Pleocoma fimbriata Lec., of moderately large size, black, rounded, not very convex, with the body, parts of the mouth, and legs clothed with very long hair. The elytra are irregularly punctured, and the head is armed with a perpendicular horn between the eyes, and the front is prolonged and bifurcated; above the insertion of the antennæ is an acute lobe. The antennæ have eleven joints, of which the last five or six form a large lamellated mass; the labrum is elongated, rounded at the apex, and deflexed. The mandibles

are pyramidal and short; the inner lobe of the maxillæ is very small, and hooked at the tip; the outer one is larger, but still small, rounded at tip, and hairy; the maxillary palpi are long and slender, the second joint equal to the third and fourth, the third being only half as long as the fourth. The mentum is nearly semicircular; the ligula is entirely concealed by the base of the labial palpi, which are moderate in length, the third joint being as long as the first and second together. The anterior coxæ are large, conical, prominent; the middle ones contiguous, prominent, conical, oblique; the elytra cover the pygidium almost entirely. The anterior tibiæ are 3-toothed, and have two small teeth above the upper tooth; the middle and hind tibiæ are expanded at tip, and have two acute teeth placed transversely about the middle on the external surface. The tarsi are longer than the tibiæ, and slender, the joints 1-4 equal, the fifth longer than the two preceding; the claws slender, with a narrow bisetose onychium. Ventral segments free, the sixth retracted within the fifth.

Of the habits of this remarkable insect nothing is known.

Tribe VII.-ACANTHOCERINI.

Mandibles and labrum corneous, prominent; antennæ 9- or 10jointed, club 3-jointed; anterior coxæ conical, prominent; middle coxæ transverse, contiguous; epimera of the mesothorax attaining the coxæ; epimera of the metathorax covered; ventral segments five, not connate; body contractile into a ball; pygidium entirely covered by the elytra; tarsi with slender claws and no onychium.

Oval, convex, smooth, shining insects, living under bark and in rotten wood. They have been considered by Lacordaire and previous authors as forming a sub-tribe of Trogini; but the difference in the side pieces of the mesothorax, which extend to the coxæ, as in all other Scarabæidæ, requires them to be separated. Other differences are found in the large size of the scutellum, and the tarsi fringed with long hairs.

Our genera are two, both having 10-jointed antennæ :—

Body partially contractile; middle and posterior tibiæ thick.

ACANTHOCERUS.

Body perfectly contractile; middle and posterior tibiæ compressed.

SPHÆROMORPHUS.

Two species of the first gènus, and one of the second, from the Atlantic States.

Tribe VIII.-NICAGINI.

Nicagus obscurus (Ochodæus obscurus Lec.) is the only member of this tribe known to me. It is an oval, convex insect, more than a quarter of an inch long, brown, densely punctured, and covered with very short pale hair. It resembles in appearance some of the Sericæ, or a nearly smooth Trox. It is found throughout the Atlantic district.

The head is rounded, moderately convex, the front finely margined; the labrum is broadly rounded, hairy; the mandibles short, pyramidal, not very prominent; the mentum is thick, triangular, hairy, pointed in front; the palpi short, the last joint oval. The antennæ are 10-jointed, the club 3-jointed, longer in the male than in the female. The anterior coxæ are large, conical, prominent; the middle ones nearly contiguous, oblique; the epimera of the mesothorax attain the coxæ. The elytra cover the pygidium. The abdomen has five free ventral segments. The legs are normal in form; the anterior tibiæ are 4-toothed, the middle and hind ones gradually thickened towards the tip in the female, but slender in the male, with one small sharp tooth and some small denticles on the outer face; the spurs of the hind tibiæ are acute in the male, obtuse in the female;, the tarsi are long and slender in the male, but shorter and stouter in the female; the onychium is narrow, and bears two long bristles, as in Lucanidæ.

I have been very much at a loss where to place this curious insect. The joints of the club of the antennæ do not appear to be capable of being brought into absolute contact, as in other Scarabæidæ, and the club therefore appears pectinate. I was, therefore, inclined to consider it as allied to the European Esalus, among the Lucanidæ, which genus it resembles somewhat in form; but the small size of the oral organs, and the triangular mentum, have induced me rather to place it as a tribe of the Laparostict Scarabæidæ, and the position here given it well corresponds both with its external form and Melolonthine sexual characters. Of its habits I know nothing.

Tribe IX.-TROGINI.

Mandibles and labrum corneous, prominent; antennæ 9- or 10-jointed, club 3-jointed; anterior coxæ rounded, subconical, prominent; middle coxæ nearly round, not oblique, contiguous; epimera of the metathorax covered; epimera of the mesothorax widely separated from the coxæ by the sternum; ventral segments five, not connate; abdomen covered by the elytra; tarsi with moderate claws, but no onychium.

The insects of this tribe are oblong, convex species, living in dried decomposing animal matter. The feet are scarcely fossorial in form; the surface is usually rough, and covered with a crust of dirt, removed with great difficulty. Our species are numerous, and belong to the genus Trox. The larger species, having the sides of the thorax not ciliate with hairs, were placed by Erichson as a separate genus, Omorgus; but the characters, as observed by Lacordaire, are indefinite, and it is not retained.*

The genus Trox possesses a distinct stridulating organ; it is an elliptical plate, with pearly reflections, occupying the upper part of the external face of the ascending portion of the first ventral segment, and is covered by the elytra; on the inner surface of the elytra, near the margin, about opposite the metathorax, is an oval, smooth, polished space, which has probably some connection with the stridulating organ.

Sub-Family II.-MELOLONTHIDAE.

This sub-family holds an intermediate position between the laparosticti and pleurosticti. The second pair of abdominal spiracles is placed in the membrane connecting the ventral and dorsal segments, as in other Scarabæidæ; in most species the third, and sometimes the fourth, at the outer limit of this membrane; the fifth and sixth pairs are in the dorsal portion of the ventral segments, but the lines connecting them do not diverge strongly, as in the pleurosticti; the seventh or last pair is usually visible behind the elytra, but variable in position; in other species, forming the first two tribes, however, the spiracles are placed as in the laparosticti, all being in the connecting membrane.

* For a synopsis of our species, see Proc. Acad. Nat. Sci., VII, 211.

The clypeus is usually prolonged and margined in front, so that the mouth is inferior, but in Glaphyrini the mandibles and labrum are prominent; the mandibles are corneous, short, pyramidal; the mentum large, quadrate, with the ligula usually corneous and connate with the mentum, though sometimes free and membranous, as in the laparosticti; the clypeal suture is usually distinct, transverse; the antennæ have from seven to ten joints, and the club is always lamellate, sometimes consisting of six or five, but usually of three joints, and is frequently longer in the males; the tarsi are always perfect, 5-jointed, with the claws variable in form, and the bisetose onychium is present in all the tribes except Hoplini.

The species feed exclusively on living vegetable matter, and it will be seen that the distinctions between it and the other subfamilies are of a negative character; the posterior spiracles do not diverge strongly, as in the pleurosticti; the middle coxæ are not oblique, as in the laparosticti (except Trogini), nor rounded and separated from the side pieces, as in that tribe. There is also a considerable difference in the adaptation of the last abdominal segments. In Melonthide the fifth ventral is very frequently connate with the penultimate dorsal, and the sixth segment, usually visible, is rendered so merely by its size and firm consistence causing it to be pushed out into view. Even when the fifth ventral is not connate with the dorsal segment, they form together a regular ring.

In the preceding sub-family the sixth ventral segment is normally visible, although sometimes of small size and retracted; in this case the pygidium or last dorsal segment is covered by the elytra, and in a manner lies upon the fifth ventral. The fifth ventral is never connate with the penultimate dorsal, and does not form with it a regular ring.

In the first tribe of Melonthidæ (Glaphyrini) the sixth ventral is quite visible, and the fifth is not connate with the penultimate dorsal, but still they are adapted together so as to form a regular ring, to which is articulated the protuberance formed by the pygidium and sixth ventral, in the same position as in Melolonthida of other tribes in which the sixth ventral segment is external.

According to the position of the abdominal spiracles, the tribes of this sub-family divide into two sets.