1914] Wheeler—American Species of Myrmica 119 
The males and females of only two of the species (M. rubida 
and mutica) are known. The workers of the five species may be 
readily separated by means of the following key: 
1. Anteroventral surface of postpetiole with a pointed or rounded tubercle or 
Bro GU beranCemereiy-.3 orci ae tet vere tian eer Che: cy, HAs eye 2 
Anteroyentral surface of postpetiole flat or at any rate without a tubercle or 
POLO GUD OLA CO ees vee pala a erciancs Soles ee tetars eh emer Seat enh eet barry at Raat 3 
2. Large species (worker, 7—8.5 mm.; female, 9.5-12 mm., male, 8.5-10 mm.) 
epinotum'subdentate; postpetiole with a small, pointed, anteroventral tuber- 
cle; deep red, posterior portion of first gastric segment blackish 
rubida Latreille. 
Smaller species (worker, 4-6 mm.), anterior border of clypeus entire, epinotum 
not subdentate, rounded in profile; anteroventral portion of postpetiole much 
PDOINS FORO OSD IN be ened oc aS Mes ROC en RENE Tee as t 
om eepmred:spetiole) subopaques oss. \on «lo Ha oc tees. osc mutica Emery. 
Black, with red thorax, petiole and postpetiole; both petiole and postpetiole 
Shimin oan Orexs ENnGers sala sheen ave ee see ete eee bradleyi Wheeler. 
4. Yellow; anteroventral tubercle of postpetiole conical or pointed . aldrichi sp. nov. 
Deep red; spot on vertex and posterior portion of first gastric segment black; 
anteroventral tubercle of postpetiole more rounded......... hunter sp. noy. 
Myrmica (Oreomyrma) mutica Emery (Fig. | d). 
Myrmica mutica Emery, Zodl. Jahrb. Abth. f. Syst. VIII, 1894, p. 3118. 
Worker: Length, 4-6 mm. 
Head subrectangular, as broad as long, with straight lateral borders and rounded 
posterior corners. Eyes at the middle of the sides. Clypeus convex, its anterior 
border very feebly sinuate in the middle. Mandibles with two large apical and 
about a dozen minute basal teeth. Antennal scapes, rather strongly curved and 
slightly flattened at the base, scarcely reaching beyond the posterior corners of 
the head. Funicular club 5-jointed. Thorax in profile with rounded pronotum 
and the mesonotum gently sloping to a rather deep constriction in front of the epino- 
tum, which has a subequal base and declivity, the former feebly convex, the latter 
sloping and nearly straight. Petiole in profile longer than high, its node bluntly 
rounded, with concave anterior and convex posterior slopes; ventral surface of 
peduncle in front with a small, acute tooth. Postpetiole scarcely longer than 
broad, a little broader behind than in front, somewhat broader than the petiole; 
its ventral surface in profile straight. Gaster a little larger than the head. Legs 
long, tibiz and femora feebly clavate. 
Subopaque; dental border of mandibles, postpetiole, gaster and legs shining. 
Mandibles, frontal area and front longitudinally rugose; remainder of the head 
longitudinally and rather indistinctly punctate-rugulose. Thorax finely rugose, 
longitudinally on the pleure, pro- and mesonotum, transversely and more coarsely 
on the epinotum. Petiole and ventral portion of postpetiole finely and densely 
punctate. Gaster and legs with small, scattered, piligerous punctures. 
Hairs white, erect or suberect, coarse, rather short, abundant on all parts of the 
body, legs and scapes. 
