60 NOTES ON MEXICAN ANTS. 
in decaying wood in midwinter. Dr. Fitch has described a 
smaller species (Formica Carye) which inhabits hickory 4 
trees, boring its passages, as he thinks, in the living wood. 
The wood on the sides of these passages is much discolored 
and softened, probably by an acrid fluid (formic acid) emit- 
ted for that purpose by the insects. 
Formica fulvacea. (Fig. 1, worker major.) “Taken in 
Cordova, where, in the woods, it ordinarily makes its nests 
in the middle branches of Bromeliaceous parasites.” 
Formica nitida. “Inhabits the mountains of Orizaba, 
where it lives in little companies under the bark of pines.” 
Formica nacerda. “Orizaba and Cordova. Found upon — | 
leaves of plants.” a 
Tapinoma. In this genus the node is usually received d 
into a depression at the base of the abdomen proper, so that — , 
at first sight it often seems to be entirely wanting. a | 
Tapinoma piceata. “Potrero (near Cordova) Inthe wood — | 
| 
f 
; 

of oaks.” 
Tapinoma tomentosa. (Fig. 2, worker; the antennæ im- 
perfect.) “Orizaba. In little societies under stones.” 
Polyrhachis. This genus has the node of the peduncle 
thickened and usually spinose (whence the generic name 
from the Greek, meaning many-pointed), having two, three, a 
or four.spines. The thorax is usually more or less armed 
with spines or hooks. 
Polyrhachis arboricola. (Fig. 3, worker, 3a, side view 
of thorax and abdomen.) “Mexico. Indigenous in the hot 
region, where it is very common. Its nest is ordinarily 












sometimes dwells a little species of Paroquet, the Conurus 
Aztec Somm.) Itis quite vagabond in its habits, and one 
sees it running around on the trunks of all sorts of trees 
and leaves of shrubs, which strongly proves it to be essen- 
tially a tree inhabitant. It causes no trouble on plantations.” 
