1976] Wilson — Worker less Parasite in Formica 279 
Type deposition. The holotype and many paratypes are in 
the Museum of Comparative Zoology, Harvard University, while 
paratypes from the holotype nest series have been deposited in 
the U.S. National Museum and Los Angeles County Natural 
History Museum. 
Discussion. In their recent review Letendre and Huot (1972) 
note that the F. microgyna group is exclusively Nearctic, its vari- 
ous species occupying a total range from central Mexico north 
to British Columbia and east to Quebec and the Carolinas. As 
W. M. Wheeler (1904) first showed in the case of F. difficilis, the 
tiny queens enter the nests of other species of Formica. These host 
colonies either lack queens of their own at the outset or else lose 
them subsequently, by means still unknown. The offspring of 
dirksi 
talbotae 
spatulata 
Figure 1 . Frontal view of head and side views of basal propodeal face and 
petiolar scale of queens of Formica dirksi Wing (holotype), F. talbotae Wilson 
(holotype), and F. spatulata Buren (paratype). 
