NEW ANTS FROM MINNESOTA, IOWA, AND WISCONSIN
WILLIAM F. BUBEN
From the Department of Zoology and Entomology, Iowa State College
Received October 14, 1941
Iowa, Minnesota, and northern Wisconsin are regions which seem to
have been neglected by American myrmecologists. Thus it is not <=ur-
prismg that new ants, especially parasitic species which tend to be rare
sporadic, or circumscribed in distribution, can be collected in these
regions.
Holotypes and most of the paratypes are to remain in the author's
collection. A few paratypes of each species will be deposited in the
National Museum and the Iowa State College collection. There are also
a few paratypes in the collection of Herbert T. Dalmat of New York Citv
who accompanied the writer on the collecting trip during which most of
these species were taken.
Formica reflexa, n. sp.
WORKER
Length, 4.65-5.27 mm.
Head, excluding the mandibles, a little longer than broad, somewhat
broader behind than in front, with convex posterior margin, evenly and
broaoJy rounded posterior corners, and moderately convex sides. Man-
dibles ^-toothed. Maxillary palpi approximately .64 mm. long. Clvoeus
feebly carinate, subangularly produced in front. Apex of frontal area in-
distinct. Frontal carinae short, about 1V 2 times as long as the diameter of
ine antennal foramina, evenly diverging behind. Eyes hairy. Funicular
joints 2-10 subequal in length, the penultimate never shorter than the sec-
ond. Pro- and mesonotum moderately convex in profile, the middle of the
mesonotum straight. Epinotum rather angulate in profile, the base and
declivity nearly straight and subequal in length. Petiole small, anterior
surface convex, the posterior surface less so: superior border unusually
blunt, approaching Polyergus species in this respect; the sides and superior
border at least slightly convex when seen from behind. Entire body more
slender and less robust than F. dakotensis.
Head, legs, and gaster feebly shining, clypeus and thorax subopaque
bhagreening on head, thorax, and gaster fine and dense, concentrically
set on the pro- and epinotum.
Erert hairs sparse; rather short on most parts of the body, particu-
larly _ on the pro- and mesonotum where they are about .03-05 mm in
.engtn. An occasional hair slightly clavate. No erect hairs on the scapes
femora, or tibiae, few on the front and mesonotum, sparse on the dorsum
ot the gaster. Pubescence extraordinary, consisting of fine hairs almost
as long as some of the erect hairs, often growing out from the surface
suberectly but sharply reflexed in the middle so that the distal end*
stride the surface. Reflexed pubescence most obvious on the Paster'
400 W. F. BUREN
Pubescent hairs numerous but not dense, nowhere concealing the sur-
face, the distance between the bases of adjacent hairs about .03 mm.
Head and thorax reddish brown, the vertex, occiput, pro- and meso-
notum sometimes feebly infuscated. Caster black to the naked eye, under
magnification often deep brown with black posterior borders to the seg-
ments. Antennae nearly black, legs dark brown.
FEMALE
Length, 5.41-6.32 mm.
Head, excluding the mandibles, as broad as long (about 1.14 mm.),
broader behind than in front, with the posterior border convex except in
the middle where it is slightly excised, the posterior corners evenly
rounded, and the sides nearly straight. Mandibles 7-toothed. Clypeus
ecarinate or nearly so. Frontal area rather indistinct. Frontal carinae
diverging behind; short, about IVz times as long as the diameter of the
antennal foramina. Funicular joints 2-10 subequal in length, the penulti-
mate joint as long as or slightly longer than the second, and only slightly
shorter than the fourth. Eyes hairy, little or no larger than in the worker.
Thorax five-sixths as wide as the head, approximately .93 mm. across
the wing insertions. In profile the pronotum and epinotum more sloping
than in F. dakotensis. Petiole low and even blunter than that of the
worker, the sides and superior border moderately convex when seen
from behind. Wings about 5.5 mm. long. Whole body much more slender
and less robust than dakotensis.
Entire body very shining, without shagreening, marked only by the
punctures from which the pilosity and pubescence arise.
Erect hairs not very numerous on any part of the body, most abundant
on the dorsum of the thorax, sparse on the head and gaster. Hairs on the
dorsum of the thorax often slightly clavate. Pubescence unique, consist-
ing of fine hair a little shorter than the erect hairs, growing out from the
surface suberectly, but sharply reflexed in the middle so that the distal
ends strike the surface. Reflexed pubescent hairs numerous but not
dense on all body surfaces, the bases of adjacent hairs about .03 mm. apart.
Pubescent hairs flexuous on the legs but usually not sharply reflexed.
In mature specimens, head deep blackish brown, most of the thorax
dark brown, the scutellum nearly black, the epinotum lighter. Gaster
black to the naked eye. Legs dark brown. Antennae black. In dorsal
aspect, the insect has a dark, almost black appearance.
Length, 6.54-7.49 mm.
Head, excluding the mandibles, distinctly broader than long, the
posterior border broadly rounded. Mandibles indistinctly 3-toothed. Eyes
hairy. Funicular joints 2-10 gradually decreasing in length, the second
about one-fourth again as long as the penultimate, and as long as the
first. Whole body more slender and less robust than in F. dakotensis.
Petiole low and blunt, the superior border straight or slightly convex
when seen from behind.
ANTS FROM MrNNESOTAHlGSVAj
Head and thorax subopaque, gasteif feebly? S&lrjitts|
Erect hairs short, numerous on the dersumof^the&hipTaic, much sparser
on the head and gaster. Pubescent haiiis longj stra^h% bot usually sub-
appressed to suberect so that it is difficult to distiii^idb between pilosity
and pubescence. Pubescence moderately sparse, nowhere concealing the
surface; denser, however, than on the worker and female.
Color black, legs brown.
Described from 53 virgin females (most of tEena partially callow) , 41
males, and 129 workers taken from a small, obscure, roadside nest near
Hibbing, Minn., August 13, 1941. This species was also found at Owatonna,
Minn. (23 virgin females and 33 workers, Augtptel7 r 1941, and 10 workers,
July 6, 1940); at Jenkins, Minn. (24 workers : staff 3 males, August 11,
1941, and 18 workers, July 10, 1940) ; and at Spirifctake* Iowa (20 workers
from four small nests, June 12, 1940, and 5 work||^ July 15, 1940) .
Differing from all other species of Formica liiS&m to the writer by
having the pubescence reflexed and the petiole unasuaHy blunt. Among
the species of Formica, rejlexa seems most closely related to dakoten&is
Emery. F. rejlexa differs from this species mainly by having the sides
of the head less convex, reflexed rather than straight pubescence, smaller
size, and the petiole very blunt rather than cttneate in profile and con-
vex above rather than truncate or excised when seen from behind.
F. ferocula is described by Wheeler as having a very blunt petiole.
This may possibly be as blunt as that, of refleZS. : F. ferocula differs
from rejlexa by having the head as broad as long, tjbe posterior border
of the head feebly excised instead of convex, tlte first four funicular
joints longer than the penultimate, the epinotum wife a slightly convex
base and distinctly concave declivity rather thaii -aritli a straight base
and declivity, the erect hairs numerous on parfef of thfe thorax and absent
on the posterior portions of the head, and by not (basing the pubescence
reflexed. F. ~ irocula was thought by Wheeler to^bei allied to the ciliata
group of species. Thus it probably is not clssely zelatefi to rejlexa.
Although the females of rejlexa are very small and definitely micro-
gynous, this species does not seem closely zelstefl t<| afty of the species
of the microgyna group. F. rejlexa can be distinguished firom all members
of this group by the unusual shape of the petipljf, t|b feflfexed pubescence,
the proportions of the funicular joints, and' l t8g ifeli, sipall, rather uni-
formly sized worker cast.
The very small, uniform size of the worbajsr, |ttr^k^ most species of
the rufa group, and the small, blunt petiole (as -fi afec^iii$d) seem to show
a highly developed parasitism.
Of the seven nests that the writer has IpuijfL fpoike were without
numerous workers of the host species, F. jusscajiiii^MSpcjjp., the subsericea
workers in all cases outnumbering the refZexf|wi}r^fers -at least several
to one. This immediately suggests permanen^ s^ci^ jfer^sitism of the
duiotic type, like that of Polyergus species. 1fn4| Jflia& relationship
with subsericea is not of the duiotic type is eSacj|>nJ^|by| the fact that
rejlexa, lacks the clypeal notch; characteristic of Mfepfeiis of Formica
4U<J W. F. BUREN
and even more timid than their hosts. Upon opening their nests, the
reflexa workers disappeared as quickly as possible, leaving the subsericea
workers to defend the nests.
F. reflexa can hardly be a temporary social parasite. In this type
of parasitism it is usually very difficult to find mixed colonies.
If reflexa is a permanent social parasite of the nondulotic type, the
females should exhibit very strong inquilinous characteristics, for it
would be fatal to seek adoption in an incipient or depauperate colony as
do all other parasitic Formica species. Instead, adoption must be secured
in a flourishing colony which can furnish enough host workers to rear
reflexa broods for at least two or three seasons. HoweVer, if the host
queen is retained as in Strongylognathus testaceous of Europe, incipient
nests could be chosen.
Much experimentation should be done with this species to determine
its exact relationship with F. subsericea.
Formica fossaceps, n. sp.
WORKER, MAXIMA
Length, 6.65-7.71 mm.
Head, excluding the mandibles, slightly longer than broad, narrower
in front than behind, with feebly excised or straight posterior border
and nearly straight sides. Clypeus evenly rounded in front, ecarinate
or distinctly carinate only at the extreme front. Clypeal fossae strikingly
deep; antennal fossae also rather deeply impressed. Maxillary palpi
short. Apex of frontal area rounded. Frontal carinae diverging, about
twice as long as the diameter of the antennal foramina. Frontal furrow
indistinct, ending in a shallow pit level with the eyes. Eyes hairless.
Scapes surpassing posterior lateral corners of the head by nearly two-
fifths of their length. Funicular joints gradually decreasing in length
toward the penultimate, the second approximately four-fifths as long as
the first and about one-third again as long as the penultimate, the third
slightly shorter than the second; joints 5-8 rather unusual in appearance,
each narrow at the base but swollen to more than 1% times the base
width near the apex. To the naked eye these joints are somewhat
bead-like.
Pro- and mesonotum not as convex as in F. rufa obscuriventris.
Meso-epinotal depression not as deep. Epinotum in profile with subequal
base and declivity, the base slightly convex, the declivity feebly concave.
Petiole large, higher than the epinotum, in profile cuneate, the superior
border very sharp. Seen from behind, the petiole broad, measuring up to
.77 mm. wide, and strongly subangularly or convexly produced upward.
Head and legs moderately shining, gaster more shining but not as
highly polished as that of the female, the shagreening on the gaster very
fine and superficial. Thorax subopaque.
Erect hairs absent on most body surfaces, present on the dorsum of
gaster near the apex, venter of gaster, venter of petiole, and coxae.
Pubescence very short and sparse, especially on the head and gaster,
iN-rs FROM aGNfresom,
rather dense only on the false l>f gaster, petiofe, fp^ofgnc^ and appendages.
Head and thorax ferruginous, appendages ibn|w<^ iiatire gaster deep
black.
WORKER, MEDIA.
Length, 5.23-6.62 mm.
Differing from the maj|r in having t&e he^dSstraight or slightly
convex behind, the clypeal ffssae a little less^ dejBp|tthe basal funicular
joints shorter in proportion to the penultimate,! thle niiddle joints less
bead-like, and the head and thorax often infuscaiecjj
WORKER, MINIMA
Length, 3.70-4.58 mm.
Differing from the major in having the head definitely longer than
broad and slightly convex behind, the clypeus distinctly carinate, the
clypeal fossae more normal in depth, funicular joints 2-10 more nearly
subequal in length, and the middle joints not beacHike. Also differing
in having the body a little less shining and the hea c| and thorax heavily
infuscated.
FEMALE
Length, 7.19-7.84 mm.
Although little shorter than the females of fe fufa obscuriventris,
strikingly more slender |tad much less massive than this species.
Head, including the iaandibles, triangular in shape} the outer borders
of the mandibles nearly idigned with the sides of tfie head; excluding the
mandibles, slightly longia? than broad (about l.M-lnns. wide) , one-third
again as wide behind as 2dt front, with straight posterior border and sides.
Clypeus evenly rounded in front, ecarinate. Clypeatf ossae extraordinarily
deep, the middle part of tbe clypeus between them strongly convex in
transverse section. Frontal carinae divergmg,:: approximately twice as
long as the diameter of the antennal f oraminas Ifrontat furrow very short
and indistinct, not reaching beyond the froatalf cafinae. Funiculi much
as in the major worker, but joints 5-8 not *s $ea|l-Bke and the second
joint only a little shorter than the first. Eyes=hE8rl<iss f 2a little larger than
those of the worker. Tho^x narrower thai Ihefhe&d, about 1.2 mm.
wide. Petiole large, cunea% ia profile, with^h^pjsugerior border, sub-
angularly produced upward when, seen fromfb^ii^iS.
Entire body, especiallyftBfe gaster, glabfpi|! afid%xiremely smooth.
Thorax a little less shinmgp&an the head ^j^g^t^. Shagreening on
the gaster scarcely perceptible, the surf ac^ n|Eirl|bdif only by the very
sparse, minute p 1 nurtures frj^mj which the pu>e&eye^arisesi
slender, scattered hairs on tps Tenter othe gfetS* fii<S:osEaei Pubescence
very fine, short, and sparsft about .Ot.02 ^rt ill l^iglh, ratter dense
only on the base of the gaafcer and appendaafesSemr&d^ sparse on the
head.
Head and thorax lighfE Ifrownish re^. p^t Atilel^ deep black
except at the extreme basfe ftfeadi lifhtfy ***'*'*'
W. F. BUREN
Mesonotum heavily infuscated in a median frontal spot and along the
parapsidal sutures. Scutellum and metanotum black.
Length, 8.06 mm.
Head, excluding the mandibles, distinctly broader than long, much
broader behind than in front. Mandibles feebly 3-toothed. Clypeal fossae
very deep. Funicular joints 2-10 gradually decreasing in length, the
penultimate a little over one-half as long as the second, the second one-
fourth again as long as the first. Petiole in profile, with convex anterior
and flat posterior surfaces; seen from behind, subrectangular, the superior
border sinuate but nearly truncate, the sides almost straight.
Head and thorax mainly opaque, the declivity of the epinotum
glabrous; gaster feebly shining.
Erect hairs nearly absent on the dorsal surfaces of the body, a few
on the gula, profuse on the venter of the gaster toward the apex. Pubes-
cence sparse, but longer and much denser than in the worker and female.
Color black, the antennae dark brown, legs light brown.
Described from 12 females, 93 workers, and 1 male taken from a nest
in wooded pasture near Winterset, Iowa, June 27, 1941. This nest was
located around the base of a bush, plant debris being used in the con-
struction of a low dome. Immediately under this dome were the brood,
workers, and sexual forms.
This species seems definitely related to F. rufa and its numerous
subspecies and varieties. It differs from all of them, however, by the
paucity of both pilosity and pubescence, the very shining surface, and
the depth of the clypeal fossae. F. rufa obscuriventris seems to be most
closely related in the structure of the clypeal fossae and the funiculi.
F. fossaceps can be distinguished from obscuriventris by the smaller size
of the female, the more shining surface of both female and worker, the
deeper clypeal fossae, the more bead-like funicular joints, the ecarinate
clypeus, and by the lack of pilosity on the dorsal surfaces of both female
and worker. In addition fossaceps has a somewhat differently shaped
head.
From rufa Integra, an eastern North American form with very sparse
pilosity, fossaceps can be differentiated by the much deeper clypeal fossae,
the proportions of the funiculi, and the shining integument. From rufa
mucescens, a Colorado form with females of about the same size, fossaceps
can be distinguished by the shining rather than opaque integument, and
very sparse rather than very dense pubescence. The writer has not seen
specimens of mucescens and thus cannot make any statements regarding
the depth of the clypeal fossae. F. fossaceps can be separated from rufa
integroides varieties haemorrhoidalis and ravida, two Rocky Mountain
forms without pilosity, by its much less robust queen, shining integument,
very sparse pubescence, and by the unusual clypeal fossae and funicular
joints.
F. fossaceps is not closely allied to any species of the microgyna
group, all of which have much smaller females, are more or less pilose,
AMT3 FROM MINNESOTA, IOWA. &&& ^KtSCto^SDT 405
and have the clypeal fossae more normal in cfejti|L ;|Although fossaceps
resembles dakotensis and its varieties in the snoothness of its integument,
it is not closely related to the latter species aSvsfiiip'via by the divergent
shapes of the head and petiole.
F. fossaceps is probably a temporary social parasite of F. fusca
subsericea.
Lasius ( Acanthomyops) pubescens, n. sp.
WORKER
Length, 3.35-4.06 mm.
Head, excluding the mandibles, as long as broajj| (aibout .88 mm.) , with
straight or feebly convex posterior border and ^|ferately convex sides.
Mandibles with 6 strong teeth and 1 or 2 indist^^llfenticuli, basal borders
edentate. Front convex, the frontal furrow=3salfeeQl Scapes surpassing
the posterior lateral corners of the head by c|^ffeventh of their length.
Funiculi feebly incrassated, the penultimate "SSfeat slightly longer than
broad; last joint broader than the penultimate, and a little longer than
the ninth and tenth taken together. Eyes hairy, with about 45 facets.
Maxillary palpi short, 3-jointed. Pro- and mesonotum moderately convex.
Meso-epinotal depression shallow. Epinotam without distinct base or
declivity, evenly rounded. Petiole small, narrow, with a transverse, trun-
cate superior border which may be sligfetlv;-,pg^ed- but not notched,
blunter than in L. (A.) interjectus and L. f &} jfcjjigeT.
Head, thorax, and gaster strongly shiEing; except where somewhat
obscured by the pubescence. ; 3& *5"
Erect hairs short and sparse, shorter aiW: 'less flexuous than on
interjectus, lacking, however, only on the sc&pes, tibiae, and middle and
hind femora. Hairs scattered over the surfaee^of'the gaster as in claviger;
more sparse than in claviger, however. Efefies^ence very dense for
Acanthomyops. Pubescence a little more abundant on the head than on
interjectus; sparser on the thorax than on &4 head, but. nevertheless,
much more dense than on interjectus; dense eda the "gaster, somewhat con-
cealing the surface. . -f .-';/-,
Color, varying from light to brownish ysSjo^ fee head never reddish.
FEMALE
Length, 4.79-5.18 mm.
Head, excluding the mandibles, a little longer! than broad, with
feebly excised posterior border and slighiiy coshes: sides. Mandibles
6-toothed, basal borders edentulous. Clypeu% ueeakly subangulate in
front Frontal carinae short, scarcely distmete
hairy,
quite convex, situated a little farther to tise ||id|S3 than in interjectus.
Scapes thickened distally, surpassing the jK3Sj|e|or| lateral corners of
the head by one-seventh of their length. FmjpeHii |boc|erately incrassated,
joints 2-9 as broad as or only slightly broads!? fhaij lqfig r the penultimate
joint about as long as broad, the second jo|B^slWty over one-half as
broad as the penultimate. Maxillary palpr|i&|rti 3-jointed. Thorax
distinctly less broad than the head; with abma^ttife s|trn shape as inter-
406 W. F. BUREN
jectus; the mesothorax a little less flattened dorsally. Petiole small, in pro-
file triangular, with nearly straight anterior and posterior surfaces, the
superior border blunt; seen from behind, narrow, the superior border
imperceptibly notched and truncate. Femora and tibiae not flattened.
Wings about 5.5 mm. long.
Thorax shining, head less so; gaster subopaque, the surface obscured
by the dense pubescence.
Pilosity of about the same arrangement as in interjectus, but much
sparser, much shorter and less flexuous. Hairs very few on gula, front,
occiput, and petiole, none on the vertex. A few hairs unevenly distributed
along the posterior borders of the gastric segments, a few also scattered
over the surface of the gaster. Pubescence particularly dense on the
gaster, less dense on the head, sparser on the dorsum of the thorax.
Color dark grayish brown, the appendages lighter.
Described from 4 females and 113 workers taken from a sandy, low
mound nest in open woodlands near Jenkins, Minn., August 11, 1941. Since
no males and but few females could be found, it is probable that most of
the sexual forms had already left the nest.
L. (A.) pubescens belongs with the interjectus group of species as
shown by the long scapes and feebly incrassated funiculi. However, it
does not seem closely related to the typical interjectus, the queens differ-
ing considerably in size, color, pubescence, and pilosity. It may be more
closely related to interjectus mexicanus which has a queen of equal size.
Judging from Wheeler's description of the latter, the queen of pubescens
can be distinguished definitely from that of mexicanus by its different
color, shorter wings, and probably also by denser pubescence. The worker
of pubescens can be distinguished from that of mexicanus by the dense
pubescence and sparse pilosity. Both workers and females can be sepa-
rated from those of interjectus coloradensis by the sparse rather than
numerous erect hairs and dense rather than sparse pubescence. From
the other species with very small females, L. (A.) occidentalis and
plumopilosus, it differs in characters too numerous for consideration.
L. (A.) pubescens can be distinguished from L. (A.) parvula M. R. Smith,
a small species from Illinois, by its sparse, short pilosity, larger eyes, and
dense pubescence.
This species may be parasitic on one of the varieties of Lasius niger.
Lasius (Acan thorny ops) clavigeroides, n. sp.
WORKER
Length, 3.48-4.02 mm.
Head, excluding the mandibles, as broad as long, with straight or
slightly convex posterior border and moderately convex sides. Mandibles
8-toothed, the basal-most tooth pointing posteriorly. Clypeus rounded
or feebly subangulate in front. Frontal carinae scarcely diverging behind.
Scapes incrassated distally, reaching the posterior lateral corners of the
head. Funiculi incrassated, the penultimate joints a little broader than
long. Eyes small, hairy, with about 30-35 facets. Maxillary palpi short,
ANTSIFROM MINNSSOlA, IOWA, ASBJ WISCONSIN 4U /
3-jointed. Pro- aiKi inesonotum moderately -cofiv^x la profile, less so
than in claviger. Itese ---of epinotum in profile moderatel;^ convex, declivity
straight; the bases about three-fifths as long af title ipeelivity. Petiole
smaller and with a? blunter superior border than cl^Jt^er;, in profile with
imperceptibly convex anterior and posterior faces; fpwfien seen from
behind, the petiole straight or faintly excised; above b\it not notched as
in claviger.
Entire body strongly shining but not quite as shining as claviger. the
surface often concealed a little by the pubescence.
Erect hairs sparser, much shorter, and less flexaous than on claviger.
nearly absent on gula, front, and femora; more abundant on the gaster
than on other body surfaces. Pubescence moderately dense on the head,
sparse on the thorax, varying from rather sparse to moderately dense on
the gaster. Pubescence on all regions usually afore profuse than on the
corresponding regions of claviger.
Color varying from light to brownish yeUo^J^iishead never reddish.
FEMALE
Length, 5.67-6.23 mm.
Head, excluding the mandibles, rnsignificantlysfji|3tder than long, with
feebly excised posterior border and slightly coftVffix sides. Mandibles
7-toothed, basal borders edentate. Clypeus sutjan-gularly produced in
front. Eyes hairy, moderately convex. Scapes thickened distally, not
quite reaching the posterior lateral corners of the head. Funiculi
clavate, the penultimate joints about 1.4 times as| broad as long; the
second joint a little less than one-half as brojad^as the penultimate.
Maxillary palpi short, 3-jointed. Thorax w^lttaf shape of claviger.
Petiole small, in profile with flat anterior aaadsjpqfterior surfaces, the
superior border blunt; seen from behind, narrQgsF^th^sides straight above,
the superior border feebly convex, sinuate, of SSintty notched. Femora
and tibiae slightly flattened, the fore femora jab^ut three times, the
middle and hind femora about four times, as lon| a|e broad. Wings about
6.3 mm. long;-
Entire insect Shining, but not glabrous- liEe (Aaviger, the shining
surface somewhat hidden by the pubescence*
Erect hairs sparser, much shorter and |esf fiexiipus. than on claviger;
lacking the microscopic plumosity which cfcarific^r^es; the hairs of many
claviger queens. JJo hairs on the front, very|fe|i' or none on the vertex
and occiput. Pubescence shorter and mudS denser ithan that of claviger,
particularly on th4 head and gaster wherie it, is? d^sse enough to give a
slight pruinose efff ctf sparser on the dorsujn <|f the .|hrax.
Color dark bljiclsish brQwa, appendages Ijjgfejteil- \Seins and stigma of
the wings pale br4wtt.
Length, 3.93-4.71 mm.
Head, exdudmg the mandibles, a ilttlfe }|ra|ide|E than long, with
moderately convex posterior border and; siJtesf aflitfie broader behind
408 W. F. BUREN
than in front. Each mandible with only a strong apical tooth as in
claviger. Scapes slightly surpassing the posterior lateral corners of
the head. Eyes very convex, hairy, situated in the middle of the sides
of the head. Maxillary palpi short, 3-jointed. Thorax slightly narrower
than the head, not as robust in profile as claviger. Petiole small, the
superior border not very sharp; in profile, with feebly concave anterior
and feebly convex posterior faces. Wings about 4.6 mm. long.
Head and thorax weakly shining, gaster moderately so.
Erect hairs shorter and sparser than on claviger. Pubescence rather
sparse, but denser than on claviger.
Color black; legs and funiculi lighter.
Described from 65 virgin females, 27 males, and 110 workers taken
from a sandy, low mound nest in oak woods near Solon Springs, Wis.,
August 15, 1941.
L. (A.) clavigeroides seems to be very closely related to L. (A.)
claviger. In the field the worker, female, and male appear like small
replicas of the corresponding phases of claviger. The striking differences
in pilosity and pubescence entitle clavigeroides to full specific rank, how-
ever. The female of clavigeroides can be distinguished from that of
claviger by the very short, sparse pilosity, much denser pubescence,
smaller petiole which is blunter above and only minutely notched if at
all, less flattened legs, and smaller size. The worker of clavigeroides can
be separated from that of claviger by its smaller size, much sparser,
shorter pilosity, somewhat denser pubescence, blunter, unnotched petiole,
and less convex sides of the head. L. (A.) clavigeroides differs from
claviger subglaber by most of the above points. In addition the queens
differ considerably in color.
L. (A.) clavigeroides workers can be distinguished from L. (A.)
parvula by their larger size, shorter, sparser pilosity and somewhat
shorter, more incrassated antennae. Queens and workers of clavigeroides
and pubescens can be readily distinguished by their antennae.
L. (A.) occidentalis differs from clavigeroides by having the petiole
very large, its superior border sharp and emarginate. and by having the
head of the female long, rectangular, and narrower than the thorax. The
pile is also more abundant than on clavigeroides.
This species is probably a temporary social parasite of one of the
varieties of Lasius niger. However. L. brevicornis was also present in the
type locality and may possibly act as the host.
