L. G. Wesson, Jr. and R. G. Wesson.
Notes on Strumigenys from Southern Ohio, with Descriptions of Six New Species.
Psyche 47:91-112, 1940.

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19391 Notes on Strumigenys 9 1
NOTES ON STRUMIGENYS FROM SOUTHERN OHIO, WITH DESCRIPTIONS OF SIX NEW SPECIES
BY LAURENCE G. WESSON, JR., AND ROBERT G. WESSON Baltimore, Md.
The following paper is a list, with biological notes, of 14 species of the peculiar and little known genus, Strumigenys, six of which are new and are here described.1 All the material was collected within 45 miles of Jackson, which is located centrally in southern Ohio.
Strumigenys (Cephaloxys) pergandei Emery In a previous paper2 it was shown that S. pergandei lives, in southern Ohio at least, near the colonies of various other species of ants, hunting the Collembola which often abound in the nests of these other species.
Since the publication of
that paper, we have found S. pergandei on more than 30 occasions in this region, and only once was it not obviously associated with another ant. Stray workers have been found in nest galleries of Camponotus herculeanus subsp. pennsylvanicus (Degeer), Formica fusca (L.), and F. truncicola subsp. integra Nyl. Three workers were found in an outlying gallery of a F. ftescct mound. The gallery led from the mound to a small kitchen midden to which the pergandei seemed to be going, not, as experiments have 1We wish to express our deep appreciation to Dr. M. R. Smith, U. S. National Museum, for his suggestions as to the relationship of several of the new forms, as well as for his loan of much cotype material for comparison.
The types of the new species are to be deposited in the collection of the Museum of Comparative Zoology, Cambridge, Mass. Para- types, when present, will be deposited in the collections of Dr. C. H. Kennedy, Ohio State University, Columbus, Ohio, Dr. W. S. Creighton, College of the City of New York, the U. S. National Museum, Wash- ington, D. C., the American Museum of Natural History, New York, and the authors.
ZWesson, L. G., Jr., Contributions to the Biology of Strumigenys pergandei Em., Ent. News, vol. 47, pp. 171-174 (1936).



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92 Psyche [ Jane-Sept.
indicated, for the debris there, but for the Collembola which lived about the refuse. Under a large, flat stone in maple woods was found a fine colony of S. pwgandei in the center of a large F. fusca var. subswim Say colony the galleries of which surrounded the pergandei nest on all sides and below. Workers were observed in the galleries of about 28 additional nests of Aphmogaster fuha Roger under stones. Four or 5 peqiandei workers could often be seen creeping away from the superficial galleries when a stone covering one of these nests was overturned. One such fidva-pergawlei association was of special interest because of its similarity to the colony in the midst of the F. subse~ca nest described above. The pergandei were nesting in a shallow, nearly circular, earthen chamber about 3 em. in diameter, imme- diately under a large, flat stone covering a colony of A. fdva, Large, flattened chambers and galleries of the fulva sur- rounded the pergandei nest for at least 8 crn. on all sides. The walls of the chamber separating the Strumigenys from the Aphasnogaster were about 1/3 cm. thick. With one ex- ception we have always found S. pergandei in the soil, that one exception being in the log mentioned below under S. dietrichi M. R. Smith.
Some farther notes from observations of this species are recorded here. The developmental periods are approxi- mately: egg, 15 to 16 days; larval stage, about 42 days; pupal stage, about 18 days. On 3 occasions workers were seen to bring- alternately left and right forelegs to the vertex of the head, rubbing the tarsi forward and placing them on the ground. Whether this was a cleaning operation or a means of transfering some substance to the substratum, or has some other significance is not known. The ant did not clean the tarsus after rubbing the head, nor did it rub any other part of its body. Workers of different colonies fight viciously when brought together. On the other hand, a colony will adopt the brood of another colony, even of a dif- ferent species of the subgenus.
Strumigenys (Cephaloxys) ornate Mayr
Two workers were found near the kitchen midden of a colony of A'p/~~~'r~ogaste~ f ulvu subsp. uquiu (Buckley) which was nesting under a large stone in a rather moist



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19391 Notes on Stmmigenys 93
hillside woods.
Another colony was found in an almost
identical situation in dense, oak woods. In the latter case a worker was first seen in a frequented gallery of A. fulva aquia under a large stone. The nest was located about 3 cm. to one side of the stone, and consisted of an irregular cavity, perhaps just a crack in the soil, barely beneath the humus. It contained not more than 20 workers. Both localities were in Pike County.
Strumigenys (Cephaloxys) deitrichi M. R. Smith We have taken this ant in Pike, Lawrence, and Adams Counties.
On 4 occasions workers were found under the bark of somewhat decayed logs in open, dryish woods. In all of these logs have been colonies of other species of ants, such as Formica truncicola subsp. integra Nyl., Aphsenogaster tennesseensis Mayr, A. lamellidens var. nigripes M. R. Smith, A. fdva Roger, Proceratium cmssicorne var. vestita Emery, Ponera coarctata subsp. pennsylvanica Buckley. One long, decayed, hickory log, covered with a tough layer of bark, was remarkable in containing colonies of at least 11 species of ants, including 5 species of Strumigenys. The log, lying on the edge of some woods, extended from deep shade through a clump of bushes into broken sunlight. The ant species, in approximate order from shade to sun, were : Strumigenys deitrichi M. R. Smith, Ponera coarctata subsp. pennsylvanica Buckley, Aphasnogaster fulva subsp. aquia, Buckley, Strumigenys pulchella Emery, Solenopsis molesta (Say), Strumigenys medialis new species, Strumigenys ros- trata Emery, Proceratium crassicorne var. vestitum Emery, Lasius niger var. neoniger Emery, Strumigenys perga~dei Emery, and Crematogaster lineolata (Say). Several work- ers of S. deitrichi were found in the loose humus in the cedar grove described below under S. missouriensis M. R. Smith. In none of these cases did we observe definite indications of an association between S. deitrichi and the other species of ants living near them, such as the presence of deitrichi workers in frequented galleries of the other. Strumigenys (Cephaloxys) clypeata Roger
A nest of clypeata was found in the duff at the base of a small pine tree a few inches from a colony of Myrmica



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94 Psyche [ June-Sept.
punctiventris Roger.
The location was on a dry sandstone
bluff in Jackson County on which many colonies of S. per- gandei had been found.3
Strumigenys (Cephaloxys) medialis, sp.n. Worker: (PI. 3, fig. 1) : Length, 2.00 mm. Sides of head converging anteriorly, the occipital lobes posterior to the antennal insertions somewhat but not sud- denly or strongly expanded; clypeus at greatest width % the length of the head exclusive of the mandibles, evenly and broadly rounded, but narrower than in S. clypeata; mandibles when closed 14 to \i the length of the remainder of the head, with the stout basal teeth hidden beneath the clypeus, the succeeding toothless space very short, the apical teeth comprising 5 pair of long, acute teeth decreasing somewhat in length anteriorly, and merging without a gap into the apical series of numerous smaller teeth; posterior border of head deeply excised ; antennal scapes broadly curved on the basal third; first joint of the funiculus dis- tinctly shorter than the fourth, the terminal joint slightly longer than the remainder of the funiculus. Thorax as in S. clypeata; the dorsum of the mesonotum somewhat flat- tened, not marginate laterally ; mesoepinotal suture distinct but not constricted; epinotal spines acute, slightly diver- gent, directed backwards ; infraspinal lamellse narrow, uni- form in width.
Petiole, postpetiole and gaster as in S. clypeata and related species.
Head, thorax and petiole coarsely and densely reticulate- ,
punctate, opaque; meso- and metapleura, dorsal surface of postpetiole and gaster smooth and shining; first gastric segment with numerous coarse longitudinal striae on the basal y^ ; sculpture of the clypeus much finer than the rest of the head, densely and finely crenulate-punctate, subopaque. Hairs on the clypeus numerous, erect, anteriorly curved, narrowly squamose at their tips, those on the sides the width of the clypeus, those in the middle somewhat shorter ; hairs on the rest of the head sparse, longer, thin, clavate, 1 or 2 on each side of the head very long and not clavate. Hairs on antennal scapes numerous, similar to those on the vertex of the head, curved toward the tip of the scapes; lesson, L. G., Jr., contribution,^ to the Biology of Strumigenys pergandei Em., Ent. News, vol. 47, pp. 171-174 (1936).



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19391 Notes on Strumigenys 95
hairs on thorax irregular, long, thin, not clavate, the ma- jority subappressed; gaster bearing 2 or 3 long hairs, usually near the base, a number of shorter hairs at the tip. Spongiform processes as in S. clypeata and related species. Color dark ferruginous, the appendages slightly lighter, the gaster darker.
S. medialis possesses the general characteristics of S. clypeata and the species related to it.
It may readily be
separated from other forms, however, by (1) the longer mandibles, which are 14 to the length of the head; (2) the more narrowly rounded clypeus, the surface of which is subopaque; (3) the pilosity of the clypeus, the hairs of which are longer, erect, feebly squamose and sharply curved apically, and (4) generally by the pilosity of the rest of the head and antennal scapes. Type locality: Beaver, Pike County, Ohio. Described from a colony of about 30 workers and several dealate females taken from the hickory log described above under S. deitrichi. The nest consisted of irregular cavities in the outer rotten portion of the log which appeared to be old galleries of beetle larvae.
The colony was transferred
to an artificial nest where, as did other species of Strumi- genys we have had under observation, they fed on living springtails. In their hunting they were quite inactive, even more so than 5'. pulchella; the workers would remain in a crouching position, head close to the substratum, mandibles closed, antennae partially folded, for a great deal of the time. Occasionally some of the dealate females were ob- served hunting like the workers. Otherwise the hunting methods of this species resembled those of S. pergandei. Strumigenys (Cephaloxys) bimarginata, sp. n. Worker: (PI. 3, fig. 2) : Length, 1.7 mm. Head, exclusive of mandibles, 3.3 times the greatest width of the clypeus, 5.7 times the length of the exposed portion of the closed mandibles. Viewed anteriorly, the sides of the head anterior to the antennal insertions are straight, con- verging, their projections lying along the exterior border of the closed mandibles; clypeus rather narrow but evenly rounded, not acute, flattened dorsally; clypeus viewed from



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96 Psyche [ June-Sept.
the side with its edge broadly and deeply grooved along the entire lateral and anterior borders, thus giving the clypeus the appearance of having 2 margins, a thin but narrow upper margin and a thicker broader lower margin which projects beyond the upper margin and is visible when the clypeus is viewed anteriorly. Mandibles rather slender and elongate, the exterior border straight "bsally, feebly convex apically ; basal tooth stout, partially concealed by the clypeus when the mandibles are closed ; succeeding toothless space very short; apical teeth comprising 7 or 8 large irregular teeth which decrease in size anteriorly to merge into the apical series of numerous small teeth. Antenna1 scapes broadly curved basally, not angulate, fourth funicular joint slightly longer than the first; terminal joint slightly longer than the remainder of the funiculus. Sides of head pos- terior to the antennal insertions suddenly expanding to a broadly circular border so that that portion of the head appears subglobose when viewed anteriorly. Posterior border narrowly and rather deeply excised. Thorax essen- tially as in S. clypeata; mesoepinotal suture distinct but not constricted ; median longitudinal carina prominent, espe- cially on the basal surface of the epinotum. Petiole, post- petiole and gaster as in s. clypeata.
Head, thorax and petiole densely reticulate-punctate, sub- opaque; vertex of head with 8 or 10 broken irregular longi- tudinal rugae. Mandibles, clypeus, sides of mesonotum, meso- and metapleura, dorsum of the postpetiole and gaster smooth and shining; basal VA, of the first gastric segment with numerous coarse longitudinal striae. Hairs on clypeus sparse, long, erect, more numerous on the edges, each hair being fairly straight at the base, curved and slightly enlarged on the apical 34, VA, to l/^ the width of the clypeus; hairs on vertex numerous, shorter, erect, clavate, curved anteriorly; antennal scapes with numerous hairs similar to those on the vertex but less clavate, curved toward the tips of the scapes; hairs on the thorax, petiole and postpetiole numerous, variable, those on the thoracic dorsum being rather long, slightly clavate, appressed, those on the petiole and postpetiole averaging longer, more erect and not clavate; gaster with sparse, long, slender, erect hairs. Spongiform processes as in S. clypeata and related species.




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19391 Notes on Strumigenys 97
Color ferruginous ; mandibles, antennae and legs slightly lighter ; gaster darker.
This very distinctive species is readily recognized by (1) the doubly margined character of the clypeal border; (2) the smooth and shining surface of the clypeus, and the more extensive shining areas on the thorax; (3) the shape of the head (4) the pilosity of the head. Type locality: Cedar Mills, Adams County, Ohio. Described from a single worker found under a piece of bark lying on the ground in a somewhat open, grassy spot in rather brushy cut-over woods. A dealated female be- longing to this species was found about 15 cm. distant in some thin, vegetable debris. Further search failed to reveal any more specimens.
Strumigenys (Cephaloxys) manni, sp. n.4
Worker: (PI. 3, fig. 3) : Length, 1.8-2.0 mm. Head 2.5 times as long as the greatest width of the cly- peus, 1.3 times the greatest width across the occipital lobes; viewed anteriorly, the sides of the head anterior to the antenna1 insertions are gently convergent, slightly convex, in outline merging without definite change of slope with the exterior borders of the mandibles ; clypeus with lateral bor- ders gently convergent, nearly straight, the anterior border truncate at, or a little anterior to, the point of intersection of the lateral and external mandibular borders; in some specimens, the anterior border is slightly emarginate, in others it is somewhat angularly convex in the middle, but the truncate appearance is not lost. Occipital lobes expand- ing suddenly but not strongly from the anterior portion of the head, at first broadly convex, then more strongly convex as the posterior border is approached; posterior border rather broadly and moderately excised. Mandibles VA, the length of the rest of the head, rather robust, the external border broadly and evenly convex; basal teeth very broad and short, partially concealed by the clypeus when the man- dibles are closed, followed without an intervening toothless space by 5 pairs of moderately long acute teeth, the third ^It gives us pleasure to name this distinctive species after Dr. W. M. Mann, from whom we have received many kind favors.



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98 Psyche [ June-Sept.
pair somewhat longer than the others, these acute teeth followed by the apical series of several much smaller teeth. Eyes small, comprising 10 or 12 facets. Antenna1 scapes % the length of the funiculi, rounded but not angulate on the basal third; fourth joint of the funiculus very slightly shorter than the first, terminal joint as long as the remain- der of the funiculus. Thorax as in S. clypeata, humeri and lateral margins smoothly rounded, somewhat flattened on the dorsum of the mesonoturn, mesoepinotal suture distinct, slightly constricted ; epinotal spines acute, thin ; infraspinal lamellae narrow, not expanded ventrally. Node of petiole in profile rather prominent, broadly convex, the anterior slope rising suddenly but gently from the peduncle, the posterior slope declining very distinctly to the junction with the postpetiole.
Head, thorax and petiole reticulate-punctate, subopaque ; mandibles, meso- and metapleura, dorsum of the postpetiole and gaster smooth and shining; first gastric segment with numerous, coarse, longitudinal striae on the basal x. Hairs on head and thoracic dorsum numerous, moderately long, thin, curved and somewhat clavate at their tips ; those on the clypeus shorter, curved laterally and anteriorly, a few on the borders of the clypeus slightly longer, curved posteriorly; hairs on antennal scapes erect, clavate on the anterior edge, more numerous and thinner dorsally, de- flected toward the tips of the scapes; hairs on the thorax more irregular in length and distribution, and less clavate; hairs on the petiole, postpetiole and gaster very long, thin, very few on the gaster.
Color, light to dark ferruginous; tarsi and antennal funiculi slightly paler; gaster darker.
Type locality: Pike County, near Sinking Spring, Ohio. Described from 32 workers obtained by sifting dirt and- humus in the small cedar grove described below under S. rnissouriensis. The spot was situated at the base of a hill where the soil above the underlying limestone was only 5 to 8 cm. deep. The ground was shaded by cedar and small oak trees and was covered with a rather thick, loose humus abounding with springtails.
In shape of the head, S. manni bears a superficial resem- blance to S. margwritse Forel, but differs from that form in



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19391 Notes on Strumigenys 99
characters too numerous to mention.
It is distinguished
generally by (1) the decidedly truncate appearance of the clypeus; (2) the long and robust mandibles; (3) the mandibular dentition ; (4) the relative prominence of the node of the petiole; (5) the character of the pilosity of the head and thorax; (6) the shorter terminal joints of the antennae.
Strumigenys (Cephaloxys) rostrata Emery
Jackson, Pike, Ross and Scioto counties. We have taken this species in both soil and wood, some- times in decidedly dry situations. Three colonies were found respectively in the hickory log mentioned under S. deitrichi, the decaying portion of a large elm tree in which also lived a colony of Aphaenogaster tennesseensis Mayr, and in a crevice in a stump in a wooded pasture, a few centi- meters from another colony of A. tennesseensis. 3 colonies were taken on the edge of some dry oak woods, all in or on the humus just under the dry oak leaves, which, with some grass and herbs, covered the ground. The nesting
site of one was a rotten hickory nut; the second was in some cavities in a small decayed stick; the third was living in a crevice of a partly buried board. Workers were found under the leaves in the vicinity of the nests, presumably foraging. They were not apparently associated with any other ants. A few dead springtails were found in one of the nests. On one occasion a colony of rostrata was found living in a chamber in dry soil under a stone. Under the stone there also ran a few galleries of Lasiu^ urnbratus mixtus var. aphidicola (Walsh).
A rostrata colony was transferred to an artificial nest for observation. While employing the same general methods of hunting springtails as the other species studied, the rostrata workers differ in being more active. Instead of crouching in one spot awaiting the advent of a springtail, they spend most of their foraging time moving over the debris in the nest. When a worker scents a springtail 2 or 3 mm. away, she crouches, and, without touching it, tries various avenues of approach until she is so close that her mandibles almost touch the springtail. Then, head lowered,



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Psyche [ June-Sept.
mandibles closed, antennae partially folded, she waits until the springtail, unaware of her presence, walks against her head. Then, seizing it with a quick snap of her mandibles, she quickly dispatches it with her sting. If, on the other hand, the springtail moves away from the ant, the latter repeats her approach. If the springtail shows no inciina- tion to move within a few minutes, the ant often acts as though impatient, and tries to examine it with her antennae, or to take it in her mandibles.
Strumigenys (Cephaloxys) pulchella Emery We have found this species on about 15 occasions, each time in dead wood. A typical habitat seems to be a log or stump or dead portion of a tree trunk, welldecayed for 3 or 4 cm. beneath the bark, moist but not wet, warm but not in full sun.
Such desirable situations are almost always in- habited by species of Aphasnogcister, Lash n* var. ame~cunus Emery, or Campondus heredeanus penns'yl- vanicus var. f errugineus
( F. ) . Whether S. pul c heIh is
definitely associated with the other species, as is S, per- gumlei, or whether it is simply a matter of such a situation being a very favorable one for other reasons, we have not determined. Although we have seldom taken pzilchella workers in the frequented galleries of other ants, the colo- nies have seemed to be much more definitely associated with a larger species than chance alone would account for. Several times when logs and stumps were broken open pvl-chella workers were seen carrying dead springtails in their mandibles, and when kept in an artificial nest they readily captured and killed these insects. They would, however, accept bits of dead flies after having been starved for a few days. Their hunting methods are similar to those of S. pergandei, but the workers are less active. They walk less around the galleries and amid the woody debris pro- vided them and often crouch for hours at a cranny. When a springtail approaches, the worker merely lowers its head, turns in the direction of the quarry and waits. Only when the springtail touches the fore part of its head and man- dibles does the pv,lohelh snap and seize it. Once a dead springtail was gently pushed cloae to a waiting pulcheUa worker. The latter crept up to about the length of its head away, then crouched, holding its antennae partially folded.



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19391 Notes on Strumigenys 101
Ì
After waiting in this position for a considerable time, it rose, extended its antennae and vibrated them rapidly, then crouched again. This was repeated two more times before the ant, as if impatient after % of an hour, walked up to the springtail and .seized it.
Winged phases were taken from nests in mid August. Strumigenys (Cephaloxys) missouriensis M. R. Smith Four colonies and numerous stray workers were found in a cedar thicket in western Pike County. The first workers were seen in and around some little-used gallaries of Aphasnogaster fulva aqka var. picea Emery under a small