THE HABITS OF PHEIDOLE ( CERA TOPHEID OLE ) 
CLYDEI GREGG (HYMENOPTERA: FORMICIDAE) 
By William S. Creighton 1 
Department of Biology, City College, New York 
Although the subgenus Ceratopheidole has been recognized for 
almost three-quarters of a century, virtually nothing is known about 
the habits of the species included in it. The present study is based 
upon four nests of Ph. ( C .) clydei Gregg. Three of these were 
situated in Deep Canyon on the grounds of the Desert Research 
Center of the University of California. This spectacular and for- 
bidding canyon, cut into the eastern slopes of the Santa Rosa Moun- 
tains, is about seven miles southeast of Palm Desert, California. The 
fourth nest was at Horse Tanks in the Castle Dome Mountains of 
Arizona. It is probable that the Deep Canyon colonies would have 
gone unnoticed had not a lucky series of events led to their discovery. 
Mr. Charles Musgrove of the Entomology Division of the Citrus 
Research Station of the University of California showed me a single 
minor worker which Professor William Ewart, also of that Division, 
had taken in Deep Canyon while sweeping for thrips. Dr. Ewart was 
good enough to point out to me bush from which the minor of clydei 
had come. Even with this advantage it was some time before the 
Deep Canyon nests were found, for their placement is most unusual. 
Gregg’s original description of clydei , published in 1950 (1) 
was based upon a small series of minor workers taken by C. P. 
Stroud near Carizozo, New Mexico. Since these were strays it was 
impossible for Dr. Gregg to give any nesting data for clydei. Later, 
however, he published on specimens of both major and minor castes 
(2) which the writer had taken from a nest at Split Mountain in 
the Anza Desert State Park, California. Certain features of this nest 
were so peculiar that both Gregg and I hesitated to accept it as a 
normal nest of clydei. It was situated in crevices beneath a weathered 
lamina of stone which had partially split off from the top of a large 
boulder that was buried in the sand of the canyon floor. The crevices 
were fully three feet above the sand and there was not the slightest 
indication that any of them extended into it. It is now clear that the 
only abnormal thing about the Split Mountain colony was that the 
boulder selected as a nest site was far smaller than usual. 
The three colonies of clydei found in Deep Canyon were in 
Trofessor Emeritus, City College, New York. 
Manuscript received by the editor November 9 , 1964-. 
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