W. M. Wheeler.
A Singular Neotropical Ant (Pseudomyrma filiformis Fabricius.
Psyche 26(5):124-131, 1919.

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124 Psyche [October
A SINGULAR NEOTROPICAL ANT (PSEUDOMYRMA
FILIFO RMIS FABRICIUS)
BY WILLIAM MORTON WHEELER:
In his "Systema Piezatorum," published in 1804, Fabricius described a remarkable neotropical ant as Formica filiformis, in the single sentence: "Formica elongata, filiformis, flava, abdominis basi nigricante, petioli binodi." In a second sentence, after the citation of the locality: "Habitat in America meridionale. Dom. Smidt, Mus. Dom. de Sehestedt," he reworded the description, with the addition of the adjective "parvum," The description un- doubtedly refers to a dealated female specimen and not to a worker, as stated by Dalla Torre in his "Catalogus Hymenopterorum" (Vol. 7, 1893, p. 56).
In 1855 Frederick Smith described all three phases of the same ant from specimens taken by H. W. Bates at Villa Nova, Brazil, but named it Pseudomyma cephalica. Smith was greatly inter- ested in the ants of the genus Pseudomyrma and the ant under consideration seems to have been a particular favorite with him, for he published more figures of it than of any other species. What interested him most was undoubtedly the very aberrant character of the female, especially of its head, for in all other species of Pseudo- myrma the female is very much like the worker. Though brief
his description of all three phases of filiformis is clear, and his draw- ings though schematic enable one to recognize the species without difficulty.
Since the time of Frederick Smith myrmecological literature contains no unequivocal reference to the worker of Fabricius' species either under the name of filiformis or of cephalica. This is because Forel, in the Biologia Centrali-Americana (1899-1900), redescribed and figured the worker from Guatemala as Ps. bicon- vexa and continued to cite it under that name till 1912 when he published the latest reference I have seen of the insect. I am cer- tain of the specific identity of biconvexa with filiformis, because during the winter of 1911-1912 1 found two fine colonies in Guate- mala, each containing, not only numerous females and males i Contributions from the Entomological Laboratory of the Buasey Institution. Harvard University, No. 161.




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19191 Wheeler~A Singular Neotropical Ant 125 agreeing with Fabricius' and Smith's descriptions of filiformis and cephalica, but also many workers agreeing perfectly with Forel's description and with a cotype of biconvexa which he kindly gave me many years ago.
The genus Pseudomyrma, owing to the great number and varia- bility of its species is one of the most difficult of ant-genera. As a
small contribution to the revision to which it must before long be submitted I give a fuller description of the worker, female and male of Ps. filiformis, with larger and more detailed and I trust also somewhat more accurate figures than those published by Smith. Pseudomyrma filif ormis (Fabr .) .
Formicafiliformis Fabricius, Syst. Piez. 1804, p. 405 Q . Leptaleafiliformis Erichson, Arch. f. Naturg. 5, 1839, p. 309 9 . Pseudomyrma cephalica F. Smith, Trans. Ent. Soc. London (2) 3, 1855, p. 168, PI. 13, Figs. 12-17, g Q d; F. Smith, Cat. Hym. Brit. Mus. 6, 1858, p. 155, PI. 10, Figs. 25, 26 g Q d; Roger, Berlin, Ent. Zeitschr. 6, 1862, p. 289. Pseudomyrma filiformis Mayr, Verhand. Zool. bot. Ges. Wien, 1863, p. 452 9 ; Roger, Berlin, Ent. Zeitschr. 1863, p. 24 9 ; Mayr, Sitzb. Akad. Wiss. Wien 61, 1870, p. 407 9 ; Dalla Torre, Cat. Hym. 7, 1893, p. 56; Forel, Sitzb. Bayr. Akad. Wiss. 1911, p. 278, Q ; Forel, Biol. Centr. Amer. Formicid. 1899-1900, p. 86 9 .
Pseudomyrma biconvexa Forel, Biol. Centr. Amer. Formicid. 1899- 1900, p. 95, PI. 4, ~i~.'10 !$ ; Forel, Ann. Soc. Ent. Belg. 50, 1906, p. 229 Q ; Forel, Sitzb. Bayr. Akad. Wiss. 1911, p. 277 g ; Forel, Mem. Soc. Ent. Belg. 20, 1912, p. 30 !$ . Worker (Fig. 1). Length 4.5-5.8 mm.
Head about 1; times as long as broad, subelliptical, with straight posterior border and evenly convex sides, scarcely narrower in front than behind; eyes about half as long as the sides, in front of the middle, rather flat. Mandibles with convex external border, apical border with two large terminal and four small basal teeth, the basal border with three small separated teeth. Clypeus short,
emarginate on each side, with a short, subrectangular median lobe. Frontal carinse short, closely approximated; frontal groove absent. Antennae short, scapes scarcely reaching the middle of the interna,l



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Psyche
[October
orbits; first and last funicular joints longer than broad, the remain- der scarcely as long as broad. Thorax slender; pronotum distinctly longer than broad, scarcely broader in front than behind, submar- ginate on the sides posteriorly, with rounded humeri, in profile evenly convex above. Mesonotum circular, rather prominent, sloping to the mesoepinotal suture, which lies in a rather deep impression bearing the metathoracic spiracles. Epinotum as long
as the pro- and mesonotum together, broader in front than behind, somewhat compressed laterally, the base much longer than .the declivity, in profile moderately convex and passing with an even curve into the declivity. Petiole more than twice as long as broad, the short peduncle passing gradually into the low rounded node which is only about $ as high as the length of the segment, a little more abruptly constricted behind, the sides scarcely compressed, its ventral surface with a small tooth anteriorly. Postpetiole Fig. 1. Pseudomyrma jiliformis Fabr. "Worker. a, in profile; b, head from above; c, mandible; d, petiole, postpetiole and first gastric segment from above. twice as broad as the petiole and about as broad as long, narrowed in front, subtriangular from above and laterally. Gaster rather long, first segment as long as broad. Legs moderately long, fore femora slightly swollen.
Subopaque or glossy; head more shining, especially above; mandibles striatopunctate; antenna1 scapes smooth and shining; body and legs very finely punctate, head and pronotum a little less densely than the remainder of the body.



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19191 Wheeler-A Singular Neotropical Ant 127 Hairs and pubescence white, the hairs short and sparse, rather uniformly distributed on the body, absent on the legs; pubescence fine, dense and hiding the sculpture on the gaster, postpetiole, petiole, epinotum and legs, so that these parts appear pruinose, more dilute on the pronotum and especially on the head. Head and pronotum yellowish red; mandibles, antennae and clypeus lemon yellow; remainder of body fuscous ; meso- and epino- turn and petiole suffused with reddish;
apical margin of first
gastric segment and base and apex of succeeding segments, tarsi, trochanters, tips of coxse, bases and tips of tibiae and femora brown- ish yellow. Mandibular teeth and ocellar region blackish. Female. (Fig. 2.) Length 6.5-7 mm.
Head nearly 24 times as long as broad, suboblong, with broadly excised posterior border and straight, parallel sides, the eyes flat, about 1 as long as the head, their posterior orbits slightly behind its Fig. 2. Pseudomyrma filiformis Fabr. Female. a, lateral view; 5, head and c, petiole, postpetiole and first gastric segment from above. median transverse diameter. Ocelli small, only slightly larger than those of the worker. Mandibles and clypeus much as in the worker. Frontal carinse very small and close together. Frontal groove represented by a shallow pit in the center of the head and a faint, impressed line running from it to the anterior ocellus. An- tennse shorter than in the worker, the scape scarcely reaching to the anterior orbit. Thorax very long and slender, nearly four times as long as broad, narrower than the head, the sides almost sub-



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128 Psyche [October
parallel, the pronotum and epinotum each forming about a third of the dorsal surface, the remaining third being formed by the mesonotum, scutellum and metanotum; the mesonotum very small, scarcely broader than long.
In profile the thorax is flat-
tened above, rounded in front and behind, the base of the epino- turn long and straight and
through a strong curve into the
short, vertical declivity. Petiole from above nearly four times as long as broad, but little broader behind than in front, with nearly parallel sides; in profile feebly and evenly convex from before back- wards, ventrally compressed and with an elongate blunt tooth near the middle. Postpetiole twice as broad as the petiole, some- what longer than broad, subtrapezoidal, somewhat broader behind than in front, with convex rounded sides. Gaster long and slender, the first and second segments longer than broad, the first but little broader anteriorly than the postpetiole. Legs short, femora, especially the fore pair, flattened and dilated. Wings very short, scarcely 4 mm. long.
More shining throughout than the worker, the fine punctures being less dense, even on the thorax and gaster. Hairs and pubescence much sparser than in the worker, the pubescence very dilute; only the base of the first gastric segment somewhat pruinose.
Brownish yellow; mesonotum, scutellum and epinotum some- times a little darker; a broad spot at the base of the first gastric segment and nearly the whole dorsum of the fourth segment fus- cous, or blackish; the middle and hind femora slightly infuscated; a minute spot in front of the insertion of the fore wing, one at each ocellus, and the teeth of mandibles black. Wings grayish hyaline, strongly iridescent, with pale brown veins and dark brown pterostigma.
Male. (Fig. 3.) Length 4.6-5 mm.
Head slightly longer than broad, subelliptical, with straight posterior border and behind the eyes with straight sides converging to the posterior corners. Eyes rather convex, about half as long as the head; ocelli large. Cheeks very short. Anterior clypeal border sinuately excised on each side, its middle produced as a distinct, bluntly pointed lobe. Mandibles convex, their apical borders finely and indistinctly denticulate. Frontal carinse short, much more widely separated than in the worker and female.



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19191 Wheeler-A Singular Neotropical Ant 199 Frontal groove distinct.
Antenn~ long, filiform, 12-jointed ; scape short, about twice as long as broad, first funicular joint as broad as long, remaining joints cylindrical, the second distinctly longer than the third. Thorax elongate; mesonotum prominent, with distinct Mayrian furrows. Petiole and postpetiole shaped some- what as in the worker but less convex dorsally, the former without a ventral tooth.
Gaster long and narrow. Legs long and slender, the femora not dilated.
Finely punctate, but the punctures more distinct than in the female, so that the surface of the body is somewhat less smooth and shining; mandibles smooth, sparsely punctate. Fig. 3.
Pseudmgrma jIlijormi8 Fabr. Male. aå lateral view; by head of same, dorsal views.
Hairs whitish, short and very sparse; pubescence rather long and abundant, uniformly investing the body and appendages. Brown; mandibles, clypeus, scape and first funicular joint, artic- ulations and sutures of the body and legs dull ivory or brownish yellow.
Wings a little darker than in the female. Type-locality : "South America'' (Smidt) . Brazil : Villa Nova (H. W. Bates).
Trinidad (Urich) .




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130 Pqche [October
Colombia: Santa Marta (A. Forel).
Panama : (Stretch) ; Bugaba and Caldera (Champion). Costa Rica (Tonduz) .
Guatemala : (Stoll) ; Pantaleon (Champion) ; Zacapa and Patulul (Wheeler).
According to Frederick Smith "all the sexes of this species were found by Mr. H. W. Bates in their formicariumy the chambers of which were excavated in dead twigs.'' The colonies which I found at Zacapa and Patulul were nesting in dead branches lying on the ground in shady places. These branches, 5 to 7' feet long and 1 to 14 inches in diametery together with their twigsy had been tunnelled throughout by the ants. The colonies were very populous, com- prising hundreds of individuals and therefore larger than those of most species of Pseudomyrma. Ps. $lij'ormis seems also to differ from many species of the genus (sericea, triplaridis, arboris-sant~~ belti, spinicola, jlavidula, etc.) in preferring to live in the cavities of dead instead of living plants. There can be little doubt that $lijormis is a rare or sporadic species. Dr. W. M. Manny who collected ants assiduously in Brazil in the region explored by Batesy failed to find it, and although I found numerous colonies of many species of Pseudomyrma in Central Ameria I saw only two of $li- formis. It seems to me not improbable that the slender, smooth, aberrant female of this ant may start her colony as a temporary parasite on some other species of Pseudomy~ma, presumably Ps. $?avidday which she so strangely resembles in color. In his paper on the classifkation of the Myrmicine (Intorno alla classificazione dei Myrmicintey Rend. R. Accad. Sc. Bologna, 191 4, p. 34) Emery states that the males of the tribe Pseudomyrmini have 13-jointed antennze. This is certainly an error. All the numerous males I have examined of the various -genera of the tribe, Pseu- domgrma, Tet~aponera ( = Sima auct .) , Pmhysima and Viticicola gen. nov. (genotype Sima tewmanni Stitz of West Africa) have 12- jointed antennte like the workers and females. Fore1 has described the following varietyy which I have not seen, as a variety of Ps. biconvexa:




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