28 Psyche [February 



colony remained up to the time when my observations ceased, 

 so it is probable that the Camponotus occupied the nest, the 

 beetle normally was with them and the occurrence of the Formi- 

 cas accidental. 



Throughout March the cockroach Ischnoptera sp. was abun- 

 dant in most of the nests. It seemed to be tolerated by the ants. 

 All ants are not so indifferent as Camponotus, and in the nests 

 of Formicas, dead and mutilated specimens are common. 



The Calif ornian ant-cricket, Myrmecophila formicarum Scud- 

 der occurs in practically every nest. 



Camponotus maculatus sub. sp. vicinus Mayr. Common, 

 though less abundant than C. maccooki, nesting under stones. 

 The only guest found was Myrmecophila formicarum, which was 

 abundant. 



Camponotus hyatti Em. Rare. Two colonies found 

 during the year. One of these, found November 4, 1909, had 

 excavated run-ways in a fallen board. This colony was small, 

 only fifteen major and minor workers being taken. On April 

 19, Mr. E. J. Newcomer took a series from a nest in a rotten 

 log. 



Formica rufibarbis var. occidentalis Wheeler. Common, 

 nesting mostly under stones. Associated with it are often 

 found small colonies of the little ant Leptothorax andrei. The 

 majority of the nests harbor Myrmecophila formicarum. 



On February 13, I found with this ant a single specimen of a 

 Hetserius, different from any of our described species. Another 

 specimen of the same was taken from a different nest on March 

 5. They were clinging to the undersides of the stones which 

 covered the nests. I have named this species Hetarius wheeleri, 

 after Dr. William M. Wheeler of Harvard University, in recog- 

 nition of his work on myrmecophily. 



Hetwrius californicus Horn was found locally only with this 

 ant. The beetle seems to be very rare in collections, but can 

 be found by careful search. Between February 27 and March 

 30, twenty one specimens were taken. They occur generally 

 singly, or two in a nest, though one nest contained five and 

 another three. Their occurrence in the first was interesting, 

 because the nest had been occupied the previous week by a 

 strong colony of Tapinoma sessile, and the beetles had either 



