The genera and species are fully described by Dr. Horn in the memoir above cited, and need no farther mention at present.

Family IX. SCOLYTIDE.

Mentum moderate in size, varying in form in some genera according to sex; without gular peduncle (except in Hylastes, where it is very small); ligula and palpi small, the former sometimes retracted, sometimes prominent.

Maxillæ exposed, palpi stout and short.

Mandibles stout, curved, more or less toothed on the inner side.

Antennæ inserted on the sides of the head, between the eyes and mandibles; composed mostly of scape and club, funicle usually very short, from 1- to 7-jointed; club large, solid, annulated, or rarely (Phlœotribus) lamellated; surface of the club more or less sensitive according to genus.

Head prominent in some tribes, deflexed and protected by the prothorax in others; eyes usually large and transverse; beak never long, frequently so short as to be not apparent. Labrum feebly developed, sometimes visible. Prothorax truncate in front, exposing the head, (Platypodido, Scolytini and Hylurgini), or prominent, convex and rounded (most Tom'cini); lateral edge not distinct,* and prosternal sutures obliterated; flanks excavated for the partial reception of the front legs in Platypodida; coxal cavities usually confluent; separated in a few genera.

Mesosternum triangular, pointed behind, or slightly truncate, episterna (Platypodido) excessively large, ascending between the base of the prothorax and elytra with the epimera small, posterior and transverse, or with the suture very indistinct; coxæ rounded, not widely separated.

Metasternum long, sometimes, (Platypodido) very long; side pieces parallel, or nearly so, not dilated in front.

Legs moderate in length, rather stout, front coxæ almost always con*Except in Scolytus, Eutomus, as has been elsewhere observed is not a Rhynchophorous insect but allied to Rhipidandrus.

tiguous; middle and hind coxæ more or less separated; tibiæ compressed, toothed or with transverse ridges on the outer side; armed with a terminal hook at the inner apical angle. Tarsi in some genera filiform and 5-jointed; in others 4-jointed, with the third joint either narrow, or dilated and bilobed; last joint long, with large, simple, divergent claws.

The insects of this family are mostly of cylindrical form, and small sizeThey are the most formidable enemies of trees, sometimes devastating the forests, especially of conifers, by appearing in incredible numbers: the burrows are chiefly between the wood and the bark, though some genera penetrate more deeply (Xyloteres, &c). The patterns made by them are complex and vary according to genus and species; those of several European species are figured in the excellent work of Ratzeburg,* and since descriptions of our species are now accessible, so that their identification is easy, I trust that those interested in the preservation of our forest trees may direct their attention to this important subject. Specimens of the ravages of these insects should be carefully collected, with individuals taken from the burrows, and these should be deposited in some museum where they will be carefully preserved for future study.

Since the publication of my revision of this family, a few additional species have been found, and a renewed study of the genera has rendered necessary some modification of the classification there proposed.

The great differences exhibited by Platypus, and its allies, indicate the propriety of separating them as a distinct sub-family, a course already adopted by Lacordaire.

First joint of tarsi as long as the others united.... PLATYPODIDÆ. 66 much shorter than the others

united..

SCOLYTIDÆ.

Sub-family I. PLATYPODIDÆ.

Head large, not covered by the prothorax, front wide, oblique or vertical; labrum small, but distinct. Beak wanting; eyes rounded, not convex, finely granulated in our species. Antennæ with large scape (elongated and curved in some foreign genera), and large compressed solid club, which is pubescent except for a small space at the base; funicle composed of four small joints. Prothorax elongate, truncate before and bisinuate behind; subsinuate on the sides; flanks broadly excavated for reception of front legs. Prosternum moderately long in front in the coxæ, which are very large, conical, exserted and contiguous in our species; space behind the coxæ very short. Pronotum considerably longer than the under surface; middle of base notched for reception of the carina of the mesonotum. Mesosternum triangular, middle coxæ narrowly separated; episterna very large, quadrate, occupying the space formed by the prolongation of the pronotum; epi*Die Forst-Insecten, Vol. i.

Synopsis of the Scolytidæ of America, north of Mexico, by C. Zimmermann, M.D., with notes and additions by J. L. LeConte, M.D. Trans, Am. Ent. Soc. 1868,

mera small, transverse, posterior and indistinct. Metasternum very long, episterna parallel, rather wide; hi ad coxa slightly separated. Ventral segments 5; first and second very short, together scarcely equal to the third, which is equal to the fourth; fifth a little longer, rounded behind; las: dorsal segment horizontal, partially or completely covered by the elytra, according as the segments are deflexed or retrac.ed.

Mesonotum

Elytra margined and perpendicularly declivous at base, striate, variously prolonged into processes at tip, according to species and sex. strongly carinate.

Legs short, thighs stout, compressed; tibiæ shorter than the thighs, stout, unguiculate, marked on the outer side with transverse ridges. Tarsi long, slender, first joint as long or longer than the three following united; fourth joint one-half as long as the third; fifth as long as the joints 2-4 united; claws long, simple, divergent.

This sub-family is represented in our fauna by a few species of Platypus found chiefly in the Southern States. The species are cylindrical, and suggest a resemblance to certain Colydiide, from which, however, they widely depart in structural characters.

PLATYPUS Herbst.

In this genus the maxillary palpi are large, flat, membranous, 4-jointed, with the joints received one into the other, and the pygidium is almost or entirely covered by the elytra. The sexual differences in the processes of the elytra are such as to make it difficult to construct a table of the species: 1. Ventral segments with elevations....

without elevations.....

2. Elevations at the posterior margin of the third segment..........

Elevations very acute, at the posterior mar

gin of the fourth segment........

3. Prothorax nearly twice as long as wide.... one-half longer than wide...... with two large discoidal punctures

2.

3.

1. flavicornis f.

2. quadridentatus 9. 3. compositus 9 4. rugulosus. 1. flavicornis : 9: Bostrichus flav.

1. P. flavicornis Chap., Mon. Plat. 154, f. 70,

Fabr., Mant. 212; Sp. Ins. i, 67; Ent. Syst. ii, 364; Syst. El. ii, 384; Herbst, Käfer, v, 118; Scolytus flac. Oliv., Ent. 78, 4, pl. 1, f. 1.

Elytra with the third interspace somewhat elevated and roughened at base; the posterior process of the elytra shorter and less acute; the declivity of the elytra concave near the tip, and the tip itself truncate and feebly emarginate. Ventral segments finely rugose, regularly convex; prothorax with a large puncture each side of the anterior extremity of the short dorsal impressed line; P. disciporus Chap., 1. c. 219, f. 123, is a variety in which the elytral process is shorter and less prominent.

. Elytra with the base of the third interspace less elevated; the posterior process longer, more acute, serrate on the outer side. Ventral surface

punctured and finely rugose, opaque; posterior margin of third and fourth segments thickened, the former with two distant conical elevations.

South Carolina, Florida and Texas, extending into Mexico. Length 5.2 -5.7 mm.; .21-.23 inch.

2. P. quadridentatus. Scolytus quadr. Oliv., 78.5; pl. 1, f. 3: Lec. apud Chapuis, Mon. Plat. 338, (err. cler.): P. Blanchardi Chap., Mon. 185, f. 96. 9. Elytra deeply striate, with a posterior process at the end of the third interspace, and a large compressed obtusely truncate one at the junction of the fifth and eighth interspaces: ventral surface opaque, densely punctured; fourth segment with two acute spines near the hind margin.

♂. Unknown.

Florida: length 4 mm.; .16 inch; occurs also in Texas, according to Mr. Chapuis, if I am correct in considering his species as the same.

3. P. compositus Say, Journ. Ac. Nat. Sc. Phila., iii, 324 (?); ed. Lec. ii, 182; Er., Wiegm. Arch. 1836, ii, 65; Chapuis, Mon. Plat. 163, f. 75, J.; P. parallelus Chap., ibid. 164, f. 76, ♂, ;? Bostrichus par. Fabr., Syst. El. ii, 384, (description of no value); ?. P. tremiferus Chap., Mon. Plat. 174, f. 85, ♂, 9; ? P. perfossus Chap., ibid. 176, f. 86, 7, 9 ; ? P. rugosus Chap., ibid. 176, f. 87, F, G.

♂. Apical part of front smooth; prothorax scarcely punctulate; elytra transversely impressed near the tip, without posterior process. Ventral segments shining, sparsely punctulate.

9. Front uniformly rugose; prothorax distinctly punctulate; elytra with the second interspace compressed and forming an acute cusp near the tip; fifth and ninth interspace prolonged into a large process, which is concave above, and tridentate at tip; the outer tooth much longer, narrow and truncate or emarginate at tip according to age of specimen, or direction of view. Ventral segments opaque, densely punctured; fifth flat, not carinate, nor tuberculate.

Illinois to Texas, Louisiana, Florida, South Carolina. Neither the figures nor descriptions of Dr. Chapuis indicate anything more, in my opinion, than slight individual variations of form and sculpture, such as I would be unwilling to admit as having specific value. Nevertheless, as I have not seen the typical specimens, I cannot be certain of the correctness of this view. The original description of Fabricius refers to a male of this or some allied species, but is quite irrecognizable, and should not take precedence over the well-defined characters published by Say. Length 4 mm.; .16 inch.

4. P. rugulosus Chap., Mon. Plat. 192, f. 103, ♂, f.

♂. Front entirely opaque, finely rugose; prothorax feebly punctulate; elytra finely not deeply striate, transversely impressed at tip, without subapical process. Ventral segments shining, sparsely and finely punctured.

9. Front entirely opaque, densely rugosely punctured (areolate in fact); prothorax unequally punctulate and punctured, less finely at the sides; ely

tra deeply striatopunctate, interspaces more convex behind; second elevated, forming a small cusp at the posterior declivity; posterior process as in the preceding, but shorter and stouter, with the three teeth of nearly equal length, the outer one broad, and not very distinctly separated from the upper one; the inferior one a little shorter and acute. Ventral segments opaque, densely punctured; fifth sometimes finely carinate, sometimes feebly tuberculate.

Cape San Lucas, Lower California; Mr. Xantus; also found in Mexico. This species is allied to the preceding, but is less elongate, the prothorax being but little longer than wide, and the deep impressed dorsal line is longer, and not terminated in front by a short, transverse impression. The sexual characters, as will be seen, are quite different.

5. P. punctulatus Chap., Mon. Plat. 199, f. 110, Q..

Texas, allied to the preceding, and apparently differs only by the last ventral segment having a strongly marked tubercle. Unknown to me.

Sub-family II. SCOLYTIDE (genuini).

The characters by which this sub-family differs from the Platypodidæ have been already sufficiently pointed out; in other respects the species differ greatly according to genus and tribe, and the chief peculiarities will be pointed out under the appropriate heads.

The genera which occurs in our fauna indicate the following tribes: 1. Prothorax not prolonged over the head, which is oblong and prominent; tarsi with fourth joint smaller or indistinct; third joint usually bilobed........

Prothorax prolonged over the head, which is deeply im

mersed and globose; tarsi filiform, 5 jointed.......

2. Ventral surface ascending obliquely,..

2.

TOMICINI.

SCOLYTINI.

HYLESINI.

Although the genera of this tribe are the farthest removed from Cossonida by their characters; they are in se respects the most nearly allied to Platypus, with which the fami ust naturally commence, on account of the relations between the latter and Brenthida.

The head is globose, or nearly so, and deeply immersed in the prothorax; the eyes are transverse, sometimes divided, (Xyloterus); the front is not prolonged into a beak; the antennæ are inserted near the base of the man dibles; the scape is long and stout, the funicle short, composed of from one to five joints, the mass large, compressed, varying in form and structure according to genus. Prothorax more or less cylindrical behind, prolonged in front over the head and much rounded, so that the anterior opening be comes very oblique, or even sometimes, almost horizontal; the sculpture is peculiar, and consists for a greater or less distance from the apex of sharp granules, or little spines; behind, the surface is smooth or punctured; the PROC. AMER. PHILOS. Soc. xv. 96. 2R