1934 ] 
Tivo New North American Ants 
213 
Lasius (Acanthomyops) parvula sp. nov. 
Worker : — Length 3.0 mm. 
Head, excluding the mandibles, only very slightly longer 
than broad, narrower in front than behind, and with 
straight or very feebly excavated posterior border and reg- 
ularly convex sides. Mandibles, each with 6 to 7 very dis- 
tinct teeth and some smaller, less defined denticulse; the 
superior surface without teeth as with L. interjectus. Eyes 
extremely small, resembling somewhat those of L. flavus 
subsp. nearcticus, apparently with not more than 6 omma- 
tidia in their greatest diameter. Antennal scapes short, 
scarcely if at all, exceeding the posterior border of the head. 
Petiole apparently lower and thicker than with L. interjec- 
tus; anterior surface convex, posterior surface flattened, and 
superior surface transverse, entire. 
Body, and coxse and femora of legs covered with rather 
abundant, moderately long, erect, pale yellowish hairs. Pube- 
scence fine and appressed, sparsely covering all parts of 
body except the appendages. 
Pale yellowish, especially the gaster, which is lighter than 
the other parts of the body. 
Described from 4 workers, the cotypes of which are in my 
collection. 
These ants were collected by Drs. T. H. Frison and H. H. 
Ross of the Illinois State Natural History Survey at Herrin, 
Illinois, on October 12, 1933. According to these gentlemen 
the ants were collected in the soil beneath a rotten log in an 
open wood lot. They were associated with Lasius niger var. 
That this species belongs to the subgenus Acanthomyops 
is clearly indicated by the 3-segmented maxillary palpi of 
the workers. At a glance one would assign the species to L. 
flavus nearcticus because of the pale color, small eyes and 
general size of the workers. I believe this to be a perfectly 
valid species as evidenced by the following characters: (1) 
the extremely small size of the worker, (2) unusually small 
eyes, (3) very short antennal scapes, (4) lack of teeth on 
the superior surface of the mandibles, and (5) pale yellow 
color. This is apparently the smallest North American 
Acanthomyops that has yet been described. 
