FAM. XI.-HISTERIDAE. Mentum corneous, sometimes large and covering the base of the maxilla, flat or slightly concave, subquadrate, sometimes emarginate or tridentate in front; ligula almost concealed behind the mentum; palpi 3-jointed, cylindrical. Maxilla with two ciliated lobes, the internal one much smaller; palpi 4-jointed, cylindrical. Antennæ geniculate, capable of being retracted, short, in the second sub-family with the first joint thick, but in the first with the first joint long, the eighth and following ones forming a compact, annulated, rounded, or (rarely) triangular club. Prothorax closely applied to the elytra; side pieces not distinct;* in most of the genera with two cavities to receive the club of the antennæ; prosternum frequently lobed in front, produced behind, articulating with the mesosternum; coxal cavities open behind. Mesosternum separating widely the middle coxæ; side pieces large, not divided, sometimes visible from above. Metasternum very large, almost connate with the mesosternum anteriorly; episterna sometimes narrow, sometimes broad, occasionally curved; epimera broad, large, separated by a fine suture, which is sometimes effaced. Elytra truncate behind, leaving two segments of the abdomen uncovered; scutellum small in the first sub-family, entire in the second. Abdomen with five free ventral segments, the first very large, the fifth very short, closely applied to the last dorsal segment, which is triangular and deflexed. Anterior coxæ transverse and not prominent in the first sub-family, globose in the second; middle and posterior coxæ widely separated, not prominent, rounded, or rather subquadrate, the latter not extending to the sides of the body. Legs short, retractile; tibiæ compressed, anterior ones usually toothed, posterior sometimes toothed; spurs distinct, those of the anterior pair very unequal. Tarsi slender, short, 5-jointed in the first sub-family (except in Acritus, where the posterior ones are 4-jointed), 4-jointed in the second subfamily; claws (in all of our genera) two, simple; anterior tarsi usually received in grooves on the anterior face of the tibiæ. * In some species there is an elevated line, simulating a suture. Posterior coxæ transverse; Anterior coxæ large, antennæ geniculate. VI. OXYTELINI. Anterior coxæ large, antennæ straight, ocelli two. VII. OMALINI. IX. PHL CHARINI. 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; 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. equal. HOMALOTA. Labial palpi very long, two-jointed; joints of hind tarsi 1-4 Labial palpi 3-jointed, joints quite distinct; PLACUSA. TACHYUSA. Antennæ slender; abdomen narrowed in front; ligula short, b. Maxilla with the inner lobe ciliate, with hairs; at the apex 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. ATIMELES. B. All the tarsi 5-jointed; Palpi with a small additional terminal joint. Maxillary palpi 4-jointed, labial 3-jointed; ALEOCHARA. Head not narrowed behind; first joint of hind tarsi distinctly elongated.* OXYPODA. Head narrowed behind; first joint of hind tarsi scarcely elongated. 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 labia 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. B. Antennæ 11-jointed (tarsi 5-jointed in all of our genera); A. Elytra longer than the breast, equably punctured; ligula not narrowed anteriorly; Abdomen margined; Mesosternum carinate; maxillary palpi filiform; First joint of hind tarsi very long. First joint of hind tarsi not elongated. Mesosternum not carinate; Maxillary palpi filiform. LEUCOPARYHUS. COPROPORUS. TACHINUS. Maxillary palpi subulate. Abdomen not margined; body finely pubescent. TACHYPORUS. CONOSOMA. B. Elytra as long as the breast, smooth, or with three rows of punctures; ligula narrowed at the apex; Maxillary palpi filiform. Maxillary palpi with the last joint conical, acute. Maxillary palpi subulate. BOLITOBIUS. BRYOPORUS. MYCETOPORUS. The species of Bolitobius usually have the head much elongated; when, however, the head is oval, they approach closely to the genas Quedius of the next tribe, but are recognized by the antennæ being inserted at the lateral margin of the front, near the eyes, and not at the anterior angle of the frontal margin, as in Quedius. Tribe III.-STAPHYLININI. In this tribe the spiracles of the prothorax are visible, but the antennæ are situated at the anterior margin of the front, and differ in position in the three sub-tribes. The anterior coxæ are large and conical; the trochanters of the hind legs are prominent; the abdomen is strongly margined. The antennæ are inserted at the anterior point of the lateral margin of the front; the thorax is smooth and glabrous, with but few dorsal punctures (except in Euryporus), and its lateral margin is single and acute, as usual. The body is usually fusiform, sometimes linear. The species are found in various situations; Quedius under stones and bark in damp forests, Euryporus and Acylophorus near water. The |