126 
William Morton Wheeler 
Color black; venter and legs brown. 
Described from two specimens imbedded in a single block (without 
a mimber) in the Geolog. Inst. Koenigsberg Coli. The same block 
contains also a fine worker of Leptothorax gracilis Mayr and several 
stell ate oak hairs. 
F. horrida differs from flori in its small size and peculiar pilosity. 
In these and other characters it is closely related to the recent cinerea 
of Europe, and in haying erect hairs on the antennal scapes is even 
more like the Californian pilicornis Emery, which is, in my opinion, 
merely a subspecies of cinerea. The eyes of horrida are naked, however, 
as in the typical cinerea , and not hairy as in pilicornis. 
Formica phaethusa , sp. nov. 
Worker (Fig. 60). Length 10 mm. 
Allied to F. rufa L. and differing from F. flori in its larger size, 
more robust stature, much shorter maxillary palpi, which reach back 
only to about the middle of the gula instead of to or slightly beyond 
the posterior border of the head, its more rounded and convex pro- and 
mesonotum, less angular epinotum and much broader and anteroposteriorly 
more compressed petiolar node, which has a convex anterior and 
flat or slightly concave posterior surface and a sharp, broadly rounded 
or straight and trans verse superior border. The eyes are proportion ally 
smaller and more nearly 
circular than in flori , the 
head is of much the same 
shape, being longer than 
broad, but the posterior 
border is less convex and 
nearly straight. The an- 
terior border of the sharply 
carinate clypeus is entire, 
rounded and not project- 
ing. The penultimate 
joints of the funiculi are 
a little shorter than in 
flori. The pilosity is very 
different, consisting of 
rather dense, long, deli- 
cate hairs covering the gaster, pronotum, dorsal surface of the head and 
coxse. Possibly other portions of the trunk bore such hairs. There are no 
traces of erect hairs on the scapes or legs, except the row of bristles on 
Fig. 60. Formica phaethusa sp. nov. 
a) Worker, K 1678; b) head of same from below. 
