RECORD: Champion, G. C. 1918. Notes on various South American Coleoptera collected by Charles Darwin during the voyage of the Beagle, with descriptions of new genera and species. Entomologists' Monthly Magazine 54: 43-55.
REVISION HISTORY: Scanned by John van Wyhe, transcribed (single key) by AEL Data, corrections by van Wyhe 9.2010. RN1
NOTES ON VARIOUS SOUTH AMERICAN COLEOPTERA COLLECTED
BY CHARLES DARWIN DURING THE VOYAGE OF THE "BEAGLE,"
WITH DESCRIPTIONS OF NEW GENERA AND SPECIES.
BY G. C. CHAMPION, F.Z.S.
Darwin, as is well known, was a keen Coleopterist, as shown by the representative collection made by him of our British forms, still preserved in the University Museum at Cambridge. During the voyage of the "Beagle," 1832—1836, he captured beetles at every opportunity, and frequently mentions them in his published Journal. These insects were sent direct to specialists for determination, and most of them subsequently passed into the British Museum, the last instalment of his unnamed collections having been presented to that Institution by Mr. C. O. Waterhouse in 1885. The conspicuous South American Carabidae, Dytiscidae, Tenebrionidae, etc., were named or described long ago by Babington, G. R. Waterhouse, and others,* but the rest of the American beetles have remained untouched to this day amongst the "Accessions" in the Museum. The unnamed specimens, including many minute forms, have recently been examined by myself, and a few of those from the Tierra del Fuego and Chile are described in the present paper; the new species from the first-mentioned region are, of course, additions to Enderlein's Fuegian list (1912). Darwin's Falkland Coleoptera have been enumerated by me in the "Annals and Magazine of Natural History" for Feb. 1918, pp. 167—186.
List of New Species described.
|Bembidiomorphum (n. g.) convexum (Carabidae).||Aulonodera (n. g.) darwini (Halticidae).|
|Micragyrtes (n. g.) ocelligerus (Silphidae).||Listroderes quadrituberculatus (Curculionidae).|
|Hydnobius forticornis (Silphidae).||Listroderes kakernis (Curculionidae).|
|Philothermus cribricollis (Colydiidae).||Antarctobius rugirostris "|
|Elmis chiloensis (Parnidae).||" laticauda "|
|Docemina (n. g.) crassipes (Halticidae).|
Antarctonomus peroni Chaud.
Hab. TIERRA DEL FUEGO, Orange Bay (type of Chaudoir), Hardy Peninsula (C. Darwin), Navarin Isl. (C. Darwin, Michaelsen), Hermite
* Note.—Hyphydrus maculatus Babington (1841), found by Darwin at St. Jago, Cape Verdes, was described by Wollaston from the same island in 1867, under the name H. crussus, the latter name of course, falling as a synonym. In the "Munich Catalogue," ii, p. 428 (1868), the locality H. Maculatatus is incorrectly given as "Brazil."
Isl. (C Darwin); STRAITS OF MAGELLAN, Punta Arenas (Delfin); CHILE, Chiloe and Ynche Isls. (C. Darwin).
There are eight specimens of this species in the Museum, left unnamed by "Waterhouse, seven of which were captured by Darwin. The ♂, unknown to Chaudoir (1861), has joints 1—4 of the anterior tarsi dilated, 2 being wider than the others, as in the same sex of Brachycoelus virescens G. R. Waterh. (duponti Chaud.).
Trechus horensis Fairm.
Hab. TIERRA DEL FUEGO, Kater's Peak, Hermite Isl. (C. Darwin), Beagle Channel (type of Fairmaire); STRAITS OF MAGELLAN, Punta Arenas (Michaelsen).
Found in abundance by Darwin on Hermite Island, in 1832.
BEMBIDIOMORPHUM, n. gen.
Mentum feebly bidentate in the centre in front; [ligula injured in the specimen dissected]; paraglossae siender, curved, short; inner lobe of the maxillae hooked terminal joint of the maxillary palpi twice the length of the preceding joint, conical, pointed at tip, that of labial palpi similar; antennae short; head with a single narrow, oblique, supra-orbital furrow placed close to the eyes, and a small juxta-ocular pore; eyes large; mandibles stout, curved inwards at tip; prothorax subcordate, sharply margined laterally; scutellum wanting: elytra oval, immarginate and truncate at base, obsoletely striate on disc, the sutural stria complete, not recurved at apex, a scutellary stria present, the margins not sinuate posteriorly, the epipleura rapidly narrowed towards apex, not reaching tip; anterior coxae separated by the truncated process of the prosternum; tibiae with short spurs, the excavated portion of the anterior pair preceded by a similar spur; tarsi smooth, the anterior pair simple, similar in the two sexes, set with short setae beneath; body convex, apterous, glabrous.
Type, B. convexum.
The type of this genus has the general facies of the Palaearctic Bembidium nigricorne Gyll., except that it is larger and more convex, and has a longer prothorax, approaching the Broscids and certain Pterostichids in this respect. The simple, inferiorly setose anterior tarsi in the two sexes, and the conical apical joint and comparatively short second joint of the maxillary palpi are its chief characters, Bembidiomorphum would perhaps be best placed near the southern Trechids, Dormeyeria Enderlein (Falklands), Oopterus Guérin (New Zealand), and Merizodus Solier (Chile, Falklands, and Tierra del Fuego). Bates, in 1882, in speaking of his Group "Bipalmati," calls attention to numerous connecting links between Bembidium, Tachys, and Trechus.
Bembidiomorphum convexum, n. sp.
Oblong, convex, brilliant, cupreous with the disc of the prothorax and elytra slightly suffused with green, green with the base and apex of the prothorax and the sides of the elytra cupreous, or brassy black, the legs, mandibles, palpi, and antennae black or piceous. the under surface aeneous. Head almost smooth, bisulcate in front, the space between these sulci and the narrow supraorbital groove appearing thickened: antennae rather stout. joint 3 slightly longer than 2, 5–10 not longer than broad, Prothorax large, wider than the head, broader than long, rounded at the sides anteriorly, and narrowed and sinuate posteriorly, the hind angles rectangular; sparsely, coarsely punctate at the base, and with a large deep fovea near the hind angles, the disc transversely wrinkled and with a narrow, sharp median sulcus, not quite reaching the base or apex. Elytra regularly oval, at the middle considerably wider than the prothorax, the humeri distinct, but obtuse; obsoletely striate on the disc, the striae becoming evanescent, towards the sides and apex, those near the suture conspicuously punctured, the interstices smooth, flat, without pores. Legs rather short, the tarsi comparatively stout.
Length 3 4/5–4, breadth 1 3/5–1 3/4 mm.
Hab. TIERRA DEL FUEGO, Hardy Peninsula near Cape Horn, Navarin Isl. (C. Darwin); CHILE, Patch Cove, north part of Tres Montes (C. Darwin).
Five specimens, varying greatly in the colour of the upper surface, the one from Tres Montes (♂) having the prothorax and elytra brilliant green and cupreous. The general coloration is suggestive of that of Cascellius nitidus G. R. Waterh., a much larger, elongate Broscid also inhabiting Tierra del Fuego.
Megadytes glaucus Brullé.
Hab. ARGENTINA; URUGUAY, etc.
Sharp, in his important work on the Dytiscidae (1882), omitted to mention Cybister biungulatus Babington (1841), found by Darwin at Maldonado, Uruguay. It is correctly placed as a synonym of M. glaucus Brullé in the "Munich Catalogue" (1868), in which, however, the locality is wrongly given as "Patagonia." There are five specimens from Maldonado in the Museum, one of which must be the type.
Nordenskjöldella flavitarsis Enderlein.
Hab. TIERRA DEL FUEGO, Lapataia Channel (type), Navarin Isl. (C. Darwin).
Described from a single (♀) example captured on Oct. 9th, 1902, by the Swedish South Polar Expedition. Darwin found another on Navarin Island, in 1832 or 1833.
MICRAGYRTES, n. gen.
Head with two prominent ocelli; eyes finely facetted; apical joint of the maxillary palpi abruptly subulate, the narrow pointed apical portion very short; mandibles acute at tip, sharply toothed towards the base within; antennae 11-jointed, 1 and 2 stout, 8–10 strongly transverse, 8–11 dilated into a stout club, 11 divided into two portions by a distinct suture, the apical portion narrow; elytra truncate posteriorly, incompletly covering the abdomen, confusedly punctured; anterior coxae contiguous, without visible trochantin, the cavities widely open behind, closed by the raised edges of the two depressions in front of the mesosternum; mesothoracic episterna narrow, those of the metasternum not visible, covered by the rather broad inflexed margin of the elytra, which is rapidly narrowed posteriorly; metasternum long, truncate behind; intermediate coxae narrowly separated; posterior coxae contiguous, the rather long trochanters placed on the same axis; abdomen rapidly narrowed posteriorly, with five free ventral segments, 1—4 subequal in length, 5 narrow, triangular; legs rather slender; tibiae spinulose externally, the spurs minute; tarsi slender, 5-jointed, 4 simple; body oblong, convex, pubescent, winged.
Type, M. ocelligerus.
The remarkable little Silphid from which the above characters are taken has the general facies of an Agyrtes, except that the elytra are not striate. It has two conspicuous ocelli, which are present, but rudimentary, in the type of the genus Pteroloma,* P. forstroemi Gyll.; open anterior coxal cavities, truncate elytra, and five free ventral segments only, as in Sphaerites; and strongly clubbed antennae, as in Colon. The mouthparts are injured in the ♀ specimen dissected, and fuller particulars of the oral organs cannot therefore be given. The possession of two ocelli is so seldom to be seen in Coleoptera that it requires special notice.
Micragyrtes ocelligerus, n. sp.
Oblong, convex, shining, finely, sparsely pubescent; nigro-piceous, the ocelli, basal margin of the prothorax, basal and apical margins and suture of the elytra, antennae, legs, and under surface testaceous, the antennal club and metasternum slightly infuscate; above rather coarsely, closely, punctate, the punctures separate one from another, the elytra obsoletely striate at the base,
* A genus at one time referred to Carabidae. The Mexican P. saliaei Matth., as stated by Ganglbauer, has no trace of ocelli, and also differs in other respects from the type, and it cannot really belong to Pleroloma. The Japanese P. discicollis Lewis should also be removed from the genus.
and with a shallow anteriorly evanescent sutural stria; metasternum closely, somewhat coarsely, the ventral segments very sparsely, minutely, punctate. Antennae reaching the base of the prothorax, joints 7—9 becoming progressively wider, 7 and 8 shorter and smaller than 9—11, the latter about equal in width. Prothorax convex, transverse, rounded at the sides, narrowed anteriorly, the angles obtuse. Scutellum small. Elytra oblong, a little wider than the prothorax, rounded at the sides anteriorly, broadly truncate at the tip. Posterior tibiae sinuously bowed inward towards the apex, and the basal joint of the anterior tarsi slightly thickened, in ♂cf.
Length 1½, breadth 7/8 mm. (♂ ♀.)
Hab. CHILE, Chiloe Island (C. Darwin).
One pair, numbered 2369 in Darwin's register. They were captured in 1834.
Hydnobius forticornis, n. sp.
Oblong-elliptic, convex, rufo-testaceous, shining. Head broad, impressed with a few minute scattered punctures; antennae with the 5-jointed club greatly developed, as long as the other joints united, 7, 9, and 10 strongly transverse, subequal. Prothorax gradually narrowed from the base, the sides almost straight, the anterior angles rounded, the hind angles obtuse; the base immarginate; very sparsely, minutely punctate. Elytra rapidly narrowing from a little below the humeri, obsoletely, irregularly, striato-punctate, the interstices flat, sparsely, very minutely punctate, and also faintly transversely strigose, the sutural stria deeply impressed. Tarsi slender.
Length 1¾ mm. (♀.)
Hab. CHILE, Chiloe Island (C. Darwin).
One specimen, numbered 2369, obviously (♀, the posterior femora being unarmed. This insect must be nearly related to H. consobrinus Fairm. et Germ. (1859), type ♂, from Concepcion, Chile; but the latter, to judge from the description, has the prothorax not so smooth and more rounded at the sides, and the elytra more coarsely punctuate-striate, with the interstices transversely rugose. Compared with the European H. strigosus Schmidt the upper surface in H. forticornis is much smoother, the prothorax and elytra are less rounded at the sides, the prothorax wants the marginal groove at the base, and the antennal club is as strongly developed as in the allied holarctic genus Triarthron. The discovery of a second species of Hydnobius in Chile is interesting from the point of view of geographical distribution. It may be noted that typical representatives of the genera Anisotoma, Cyrtusa, Colenis, and Colon have been recorded from Central America, all unexpected additions to the fauna of that region.
Philothermus cribricollis, n. sp.
Oblong, shining, nigro-piceous above, piceous beneath, the head, palpi, antennae, and legs ferruginous. Head somewhat closely, conspicuously punctuate; antennae about reaching the base of the prothorax, 11-jointed, the club freely 2-jointed, 10 strongly transverse, joint 9 also transverse and considerably wider than 8. Prothorax convex, much broader than long, feebly rounded at the sides, gradually narrowing from a little before the base to the apex, the anterior angles prominent, the reflexed lateral margins narrow, the basal foveae deep; very coarsely, closely punctate. Elytra moderately long, slightly rounded at the sides, and at the middle wider than the prothorax, the margins without projecting carina, the humeri angulate; with rows of coarse subapproximate punctures placed in shallow striae, the interstices almost flat, sparsely punctulate. Beneath sparsely, the prosternum and the sides of the metasternum coarsely, punctured; metasternum sulcate down the middle.
Length 2½–3 mm.
Hab. CHILE, Chiloe Island (C. Darwin).
Four specimens, numbered 2369 in Darwin's register. This species is larger and has a more coarsely punctuate prothorax than any of the described members of the genus known to me. The antennae have a freely articulated 2-jointed club, as in P. depressus Sharp, from Japan, P. cerylonoides Reitt., from Brazil, etc. In the allied genus Cerylon, the antennae are 10-jointed and the club solid. The enlarged ninth antennal joint in P. cribricollis might, perhaps, be counted as belonging to the club.
Morychastes australis Blanch.
Hab. TIERRA DEL FUEGO, Orange Bay, Perrier Isl.; STRAITS OF MAGELLAN, Port Famine.
Two examples found by Darwin agree with Enderlein's figure of M. australis, that of Blanchard being unsatisfactory. They are labelled "Bahia," possibly in error, the handwriting being different from that attached to the specimens mounted at an earlier date.
Elmis chiloenis, n. sp.
Oval, very shining black above, piceous beneath, the antennae, anterior margin of prothorax, and legs rufo-testaceous. Antennae very slender. Prothorax transversely convex, a little broader than long, feebly rounded at the
sides, not much narrower at the apex than at the base, the anterior angles prominent; finely, shallowly canaliculate down the middle, and with a conspicuous submarginal ridge running parallel with the raised margin, the disc with a few extremely minute scattered punctures. Elytra oval, rather short, somewhat acuminate at the tip, convex on the disc anteriorly; shallowly seriato-punctate towards the sides and apex, almost smooth on the convex portion of the disc, and with two submarginal carinae, the lower one in line with the raised margin of the prothorax. Pro- and metasternum and abdomen, with a broad, shining, smoother space down the middle, the anterior portion of the metasternum depressed between the intermediate coxae, and the depression limited on each side by an oblique ridge; ventral segment 5 not longer tibiae than 2–4 united. Legs rather slender, the intermediate and posterior tibiae sinuous within.
Length 1 1/3–1½ mm.
Hab. CHILE, East coast of Island of Chiloe (C. Darwin: Dec. 1834).
Four specimens, labelled by Darwin as having been found under stones in a small stream, and numbered 2338 in his register. A minute, convex, very shining, black form, with reddish legs and antennae, related to E. sulcicollis Sharp, from the mountains of Chiriqui, and E. laevigatus Grouv., from Brazil, differing from both of them in having the prothorax less narrowed anteriorly and more finely canaliculate on the disc; E. sulcicollis, moreover, has a raised plica at the base of the elytra, which is wanting in the present insect. E. chiloensis could, perhaps, be included under the section or subgenus Esolus Muls. It cannot be identified with any of the five species of Elmis, described by Germain from Chile, three of which are from Quillota.
DOCEMINA, n. gen.
Antennae narrowly separated at the base, 11-jointed; terminal joint of maxillary palpi acuminate; prothorax margined laterally, without longitudinal impressions or transverse groove on the disc at the base; scutellum small, transverse; elytra striato-punctate; anterior coxae narrowly separated, the cavities closed behind; metasternum very short; ventral segments 1 and 5 subequal in length; legs stout; femora thickened, the posterior pair much stouter than the others; tibiae comparatively short, the posterior pair not reaching the apex of the elytra and without definite spur at the tip; tarsi with joints 1–3 spongy-pubescent beneath, 1 as long as 2 and 3 united, 2 transverse, 3 bilobed, 1 strongly dilated in ♂, the claws small, angularly dilated at the base; body oblong, apterous, metallic.
Type, D. crassipes.
The single species referred to this genus is not unlike Docema C. O.
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