774 Bulletin American Museum of Natural History. \Yo\. XXIII, 



sis. Owing to its retiring habits and small size, it is very easily overlooked. 

 A few isolated nests were found in the open fields and among the cafetals 

 and platanals along the turnpike which winds through the picturesque 

 mountains between iVrecibo and Ponce. These nests and one found in the 

 curiously eroded country about Vega Baja between San Juan and iVrecibo, 

 were small, obscure craters less than 8 cm. in diameter, made of earth of a 

 different color from that of the surrounding surface and therefore brought 

 up from some little depth. I made several attempts at excavation but was 

 never able to find the fungus gardens. Finally I discovered a nest in moist 

 red clay under a stone on the shady slope of Mount Morales near Utuado at 

 an altitude of about 400 m. The ants, about .30 in number, had constructed 

 a small tubular entrance at the edge of the stone and had excavated a tenuous 

 gallery about 5 mm. in diameter for a distance of several cm. along the sur- 

 face covered by the stone to a small irregular chamber. In this I found the 

 fungus garden which consisted of a mass, hardly more than 2 c. cm. in volume, 

 of caterpillar droppings, studded with bromatia Avhich differed from those 

 of Cyphomyrmex rivwsus only in the somewhat greater volume of their 

 component cells (PI. LlII, Fig. 44). This difference is, however, probably 

 of little importance, as the material from which the figure was drawn was 

 more recently preserved than that represented in PI. LIII, Fig. 43. As C*. 

 mhnitus and Mycocepurus borinquenrnsis occur in the same localities it is 

 quite possible that both ants may cultivate the same species of fungus. 



These observations though very meagre, are nevertheless sufficient to 

 prove that in its habits Mycocepurus is much more closely related to Cypho- 

 myrmex than to any of the subgenera of Atia. It would be ])ermissible 

 therefore to regard Mycocepurus as an independent genus. 



10.^ Myrmicocrypta brittoni sp. nov. 



My brief glimpse of the habits of this Porto Rican ant would be hardly 

 worth recording, were it not that no observations have been published on 

 the habits of the remarkable genus Myrmicocrypta. M. brittoni was seen 

 only at Santurce, a suburb of San Juan, while I was accompanying Pro- 

 fessor N. L. Britton on a botanical excursion. The ants were nesting in 

 the sea-beach just above high-water mark and over a narrow strip of the 

 adjacent shore in a large grove of cocoanut palms. The black workers 

 stood out in strong contrast with the white sand over which they Avere mov- 

 ing in the bright sunlight. The nests, which were very numerous and often 

 only a few meters apart, resembled those of Trachymyrmex turrifex as they 

 were in the form of flat, circular craters, 8-10 cm. in diameter, very shallow 

 in the middle and with the vertical entrance S'allerv terminatins: on a small 



