A NOTE ON PHEIDOLE ( MACROPHEIDOLE ) 
RHEA WHEELER (HYMENOPTERA: 
FORMICHUE) 
By Robert E. Gregg 
Department of Biology, University of Colorado 
This species was described by Wheeler (1908), from 
a single, very large, dealated female collected at Nogales, 
Arizona. Though later synonymized (Wheeler, 1915), 
with Pheidole fimbriata Roger of tropical America, M. R. 
Smith (1943), has reviewed in detail the status of Phei- 
dole rhea , drawing pertinent distinctions between it and 
fimbriata. He has shown that rhea deserves specific 
rank, and has provided a description of both the soldier 
and the worker castes. 
Through the assistance of Mr. L. F. Byars and Mr. 
J. B. Zuck, I have received a large series of specimens 
of Ph. rhea from the type locality, representing all castes 
with the exception of the males. The ants were obtained 
at different periods from the same colony located near 
the top of a dry hillside on Washington Drive, Nogales, 
Arizona. The site was characterized by very rocky soil 
originally covered with coarse desert grasses and weeds. 
Fortunately, my wife and I were able to visit the spot in 
April, 1948, and collect additional material before the 
nest was completely destroyed by landscaping. It was 
first discovered under a stone, but had moved after be- 
ing disturbed. The total number of specimens secured 
are as follows, according to caste : 201 soldiers, 262 
workers (media), and 274 workers (minima). The spe- 
cies is highly polymorphic, and for convenience several 
size classes of individuals are grouped as media, al- 
though no sharp gaps are detectable in the series from 
largest to smallest individuals. One dealated female was 
captured by Mr. Zuck from under a stone, and though 
isolated, is believed to have come from the same nest as 
70 
