Vol. XXVII, pp. 93-96 
May 11, 1914 
PROCEEDINGS 
OF TUF. 
BIOLOGICAL SOCIETY OF WASHINGTON 
DESCRIPTION OF A NEW SURSPECIES OF POGONO- 
MYRMEX OCCIDENTALIS CRESSON 
FROIM NEVADA. 
BY frp:derick M. (JAIGE. 
[Museum ol' Zoology, XJuiversity of Michigan.] 
During the suuiiiier of 1912 the Walker-Newcoml) Expedition 
of the University of Michigan collected in northeastern Nevada 
a series of specimens of an ant vdiich, although clearly allied to 
Pogonoinynnex occidentalis Cresson, diffei’S from this long estab¬ 
lished form sufficiently to require subspecific recognition. The 
series comprises some hundreds of specimens which are in the 
Museum of Zoology, University of Michigan. 
I am indebted to Prof. W. M. Wheeler, of the Bussey Institu¬ 
tion, for examining specimens of this form and for the gift of 
specimens of P. occideDtalis and P. roinanche for comparison. 
Pogonomyrmex occidentalis ruthveni* subsp. nov. 
Worker. — Ix^ngtli, ().5-S.5 inni. 
Head recdaiigulcir, exclusive of tlie T-toothed luaiidibles, nearly as l)road 
as long, posterior border straight. Clypeus rather broader posteriorly with 
that margin usually straiglit or very slightly notched at its union with the 
frontal area, anterior border witli abroad, arc-like excision, rather dee])er 
than in typical P. occidentalis. Frontal area triangular, as broad as long, 
slightly depressed, with a very distinct median carinula. Flyes in middle 
of lateral surfaces of head. Antennal scapes hardly extending to midway 
between the eyes and the i)osterior corners of the head. Thorax of tlu‘ 
usual shape with two slender epinotal spines which are longer by at least 
half than the di.stance between their bases and directed ohh(piely njnvard, 
outward and backward. Fetiole lacking the ventral tooth, excei)t that it 
may he very faintly indicated as a slight (udargcunent in .‘^ome specimens. 
Post[)etiole as in tyi)ical form, ( iasterand legs ot the usual configuration. 
♦Named for Dr. Alexander U. Ruthven. Director of llie Museum of Zoology, ruiver- 
sity of Michigan, who was in charge of the liehl work iu Nevada. 
20— Pkoc. BiOJ,. Soc. W.tsji., Vol. XXVIl, I'.lH. 
( 1 );',) 
