1912] Wheeler — Ants of the Genus M yrmecocystus Wesniael 179 



p. 359) on MacCook's authority, probably refers to the subspecies 

 mojave {vide infra) . During November 19101 found a single colony 

 of horti-deorum in Miller Canyon, Huachuca Mts., Arizona, at an 

 altitude of about 5,600 ft., and Mr. A. O. Garrett has taken it at 

 Gai-field, Utah, near the southern end of Great Salt Lake. This 

 is the most northern point at which any of our Myrmecocysti have 

 been taken. 



M. mexicanus navajo Wheeler. 



The types of this subspecies which is easily distinguished by its 

 small size, the much greater convexity of the base of the epinotum 

 and the erect hairs only on the anterior surfaces of the antenna! 

 scapes, are from Albuquerque, New Mexico. I have recently 

 received a number of workers, which agree in all respects with the 

 types, from Kennedy in the same state (W. D. Hunter). 



M. mexicanus mojave WTieeler. 



The discovery of the males and females by Mr. P. Leonard at 

 Point Loma, Gala., shows that this subspecies is very clearly 

 marked. It was found some years ago at Pasadena, Gala., by 

 Mrs. Elizabeth Grinnell, who kindly permits me to publish a 

 photograph which she took of a number of living repletes (Fig. 1). 

 Winged females have been taken by Mr. C. F. Baker at Glaremont, 

 Gala., and during December, 1910, I found numerous colonies 

 containing workers and males, on the grounds of Pomona Gollege 

 in the same locality. As my original account of the worker is 

 very brief I give a somewhat more explicit description in connec- 

 tion with that of the other unpublished phases. 



Worker. Length 4.5-5 mm. 



Head only slightly longer than broad, subrectangular, but little narrower in 

 front than behind, with rather straight sides. Mandibles short and rather convex. 

 Eyes large and convex, more than half as long as the cheeks. Mesonotum and 

 neck of pronotum distinctly shorter than in the other forms of viexicamis, the 

 pronotum being as broad as long. Base of epinotum more convex than in mexicanus 

 and horti-deorum but less convex than in navajo. Border of petiole somewhat less 

 blimt than in the other forms, its border sometimes impressed or feebly excised in 

 the middle. 



Body a little more opaque and pubescence and pilosity somewhat more abundant 

 than in horti-deorum; coloration, especially of the gaster, more sordid or brownish 

 yellow. In some specimens the gaster is uniformly brown. Head reddish behind; 

 antennae, palpi and legs pale or whitish yellow. 



