1907.] Wheeler, Fungus-growing Ants of North America. 709 



hurst and a winged individual from Lucaston, New Jersey agree in having 

 a dark spot on the middle of the pronotum, one on the postpetiole and in 

 having the infuseation of the head and middle of the gaster more extensive. 

 If we regard the New Jersey specimens as representing the typical form of 

 the species it Avill be necessary to distinguish the darker southern form as a 

 variety, for which I would suggest the name obscurior var. nov. 



6. Atta (Trachymyrmex) turrifex Wheeler. 



Wheeler, Psyche, June, 1903, pp. 100-102, fig. 6a, $ $ . 



Worker. (PI. XLIX, Fig. 3.) Length: 3-3.75 mm. 



Head without the mandibles a httle longer than broad, slightly broader behind 

 than in front, with obtusely excised posterior border, rather straight sides and promi- 

 nent posterior angles. Eyes convex, in front of the middle of the head. Mandibles 

 pointed, 7-8-toothed. Clypeus sinuately and rather deeply excised in the middle. 

 Frontal area triangular, indistinct. Frontal carinse with large round anterior lobes, 

 somewhat concave in the middle, and continued back as a pair of diverging ridges 

 nearly as far as the posterior corners of the head, but not meeting the almost equally 

 long lateral carinas. Antennae robust; scapes reaching only to the posterior corners 

 and fitting into deep grooves between the frontal and lateral carinse. Upper surface 

 of head, with the exception of these grooves, covered with tubercles, two pairs of 

 which on the superior and inferior portions of the occipital corners are larger than 

 the others and bidentate. Scapes covered with similar but smaller tubercles. 

 Pronotum on each side -with an acute downwardly directed inferior spine; above 

 with a pair of rather long, acute lateral spines and a shorter bifurcated median spine. 

 Mesonotum with two pairs of thick blunt spines. Mesoepinotal constriction very 

 pronounced. Epinotimi with subequal base and declivity at right angles to each 

 other in profile; the former convex, the latter concave; spines acute, nearly as long 

 as the base, directed vipward, backward and outward and prolonged forward at 

 their bases as a pair of subparallel, crenated ridges lying between a shorter pair of 

 similar lateral ridges. All the thoracic spines, with the exception of the inferior 

 pronotal pair, are covered with small tubercles. Similar tubercles are also scattered 

 over the dorsal surface of the thorax between the spines. Petiole from above as 

 broad as long, nearly square, with a transverse row of four equidistant tubercles 

 across its middle and connected with the median pair by longitudinal ridges. There 

 is another pair near the posterior edge of the segment. Postpetiole twice as broad 

 as the petiole and nearly twice as broad as long, impressed in the middle behind and 

 covered with small tubercles. Gaster suboblong, with straight anterior border and 

 subparallel sides, a little broader behind than in front, convex above and below; 

 first segment with longitudinal ridges half way down its sides, a faint median and 

 two lateral depressions. Its whole surface is covered with .small tubercles which 

 are connected with one another by a net-work of indistinct ridges. Legs stout, and 

 as far as the second tarsal joint, covered with tubercles which are somewhat smaller 

 than those on the body. 



Mandibles with shining, coarsely striatopunctate tips, and opaque, finely striated 

 ba.ses. Remainder of liody opaque, obscurely granular and more or less rugulose. 



