232 PROCEEDINGS OF THE ACADEMY OF [Feb , 



muiiicate by means of narrow passages with the galleries and chambers 



of the Myrinica. They obtain their food by licking the surfaces of the 



Myrmica and by regurgitation. All sorts of transitional forms occur 



between the Avorkers and queens (ergatoids and macroergates with 



from one to three ocelli). 



6. Leptothorax Schaumi Roger. 



L. Schaumi Roger, Berl. Ent. Zeitschr., VII, 1863, p. 180, No. 70. ^ . 

 L. Schaumi Mayr, Verb. Zool. bot. Ges. Wien, XXXVI, 1886, p. 451. O'. 

 L. Schaumii Dalla Torre, Catalog Hvmenopt., VII, 1893, p. 127. 

 L. Schaumi Emery, Zool. Jahrb. Abth. f. Syst., VIII, 1894, p. 320. 



Worker (PI. XII, fig. 7). — Length 2.5-2.75 mm, 



Mandibles 5-toothed. Clypeus convex without median impression; 

 its anterior border rather straight. Antennae 11-jointed; scape reach- 

 ing hardly to half way between the eye and the posterior angle of the 

 head, funiculus with a distinctly 3-jointed club; first funicular joint 

 almost as long as joints 2-5 together; joints 2-7 distinctly broader than 

 long; terminal joint fully as long as the two preceding joints. Thorax 

 rather short, flattened dorsally and laterally, broader in front than 

 behind, with distinct and rather sharp humeral angles, and with a 

 constriction at the mesoepinotal suture. Epinotal spines very short, 

 dentiform, not longer than l3road at their bases. Petiole seen from 

 above oblong, Ih times as long as broad, its sides parallel except at 

 the peduncle which is narrower; in profile the anterior dorsal slope is 

 concave and about the same length as the straight or somewhat con- 

 vex posterior slope ; ventral surface with a distinct tooth directed for- 

 ward. Postpetiole scarcely half again as broad as the petiole, distinctly 

 broader than long, oblong, with distinct though rounded anterior 

 angles. Its dorsal surface is evenly semicircular in profile. Gaster 

 of the usual shape, with small but distinct anterior angles. 



Clypeus with sharp longitudinal rugse, two of which, near the middle, 

 are more prominent than the others. ]\Iandibles with distinct longi- 

 tudinal rugse. Head, clypeus and mandibles with a silky luster, the 

 first traversed bj^ fine parallel rugse separated by rows of foveolate 

 punctures, which are clearest in certain lights on the posterior lateral 

 surfaces and cheeks. Thorax, petiole and postpetiole opaque, covered 

 uniformly with foveolate punctures. Gaster smooth and shining. 



Hairs moderately numerous on the bod}^, white, erect, clavate; 

 short on the head and thorax, much longer on the gaster and of inter- 

 mediate length on the pedicel. Hairs on the antennae and legs minute, 

 non-clavate, appressed. 



Yellowish-red, the edges of the mandibles black. Gaster in some 

 specimens dark-ljrown throughout, in others yellow or with much of 



