PSYCH B. 



y 



NEW AGRICULTURAL ANTS FROM TEXAS.* 



WILLIAM MORTON WHEELER, AUSTIN, TEX. 



PoGONOMYRMEX dESERTORUM, sp. nov. 



Worker. Length 5.5-6.5 mm. 



Head rectangular, exclusive of the 7-tooth- 

 ed mandibles slightly broader than long ; 

 posterior margin slightly concave. An- 

 terior border of clypeus broadly but faintly 

 excised. Frontal area triangular, as broad as 

 long, with a distant median carinula. Eyes 

 in the middle of the lateral surfaces of the 

 head. Antennal scape reaching to midway 

 between the eye and the posterior corner of 

 the head. Thorax of the usual shape, with 

 two rather slender epinotal spines about as 

 long as their distance apart at the base, di- 

 rected oblic|uely upward, backwards and out- 

 wards. Petiole compressed at the base, its 

 peduncle shorter than its node, which is 

 pointed in front so that the ascending dorsal 

 surface forms an obtuse angle in profile; 

 posterior descending dorsal surface gently 

 convex ; lower surf.ace of petiole with a very 

 distinct downsvardly directed tooth. Post- 

 petiole campanulate, slightly broader than 

 long, its ventral protruberance very small but 

 distinct. Gaster and legs of the usual con- 

 figuration. 



Mandibles with coarse, parallel striae. 

 Frontal area smooth and shining. Clypeus, 

 sides and upper surface of head traversed by 

 very delicate parallel rugae, which are very- 

 close together and scarcely divergent pos- 

 teriorly. Interrugal punctures indistinct 

 and in a single row between each pair of 



^Contributions from the Zoological Laboratory of the 

 University of Texas, No. 34. 



rugae. Posterior angles of head smootli and 

 shining. Thoracic and coxal rugae mostly 

 transverse, even on the meso- and metapleu- 

 rae. Infraspinal facet of epinotum smooth 

 and shining. Petiole, postpetiole and legs 

 covered only willi delicate microscopic retic- 

 ulation. 



Trunk and legs beset with bristly pale 

 yellow hairs which are erect on the dorsal 

 surface of the head and thorax and suberect 

 on other portions of the body and append- 

 ages ; the erect hairs on the head are only 

 about half as long as those on tlie thorax. 

 Lower surface of head and mandibles with 

 the usual beard of long i-ecurved hairs. Pu- 

 bescence none. 



Whole ant yellowish red with the ex- 

 ception of the eyes and dentate mandibular 

 edges, which are black. 



This species was taken (Dec. 19, 1901) 

 in several localities in Presidio County, 

 Trans-Pecos Te.xas, from the southern 

 end of Fresno Canon northward through 

 Alamito to San Esteban, which is located 

 a few miles south of Marfa. These 

 localities have an elevation of 4000-5000 

 ft. The species occurs also in New 

 Mexico, whence I have received a worker 

 taken by Prof. T. D. A. Cockerell at 

 Mesilla Park ("in the r/iu'/iea zone.") 



At first sight 7^. descrtorum resembles 

 P. califoniiacs Buckley on account of 

 its yellowish red color. It differs, how- 



