1907.] Whciicr, Fungus-growing Ants of North America. 687 



are so easily torn asunder while the nest is being uncovered." Even in 

 captivity these ants persisted in hanging their gardens to the sities of the 

 glass dishes in which they were kept. " ^Microscopical examination shows 

 that the envelope consists of the same, loop-like hj^jhse as the remainder 

 of the garden. Such a structure cannot be produced by the fungus except 

 vnider extraneous influences. We must assume that the ants bring about 

 the development of the envelope, that they direct or coerce the gro^^'th of 

 individual hyphfe v>'ith their antennje or fore legs, spread them out into a 

 layer and bite off the recalcitrant hyphse that grow out from the surface." 

 INIoeller succeeded in cultivating the mycelium of the Apterostigma gardens 

 in artificial media, but he failed to obtain the fruiting stage. He believes, 

 however, that the fungus is a basidiomycete. 



The two species of Ci/phomyrmex observed by Moeller were found nesting 

 under bark or in rotten wood like Apterostigma. The largest gardens 

 of C. strigatus are only 8 cm. long, whereas those of C. auritus may attain 

 a length of 15 cm. and a breadth and height of 5 cm. These gardens are 

 never pendent and never enclosed in a mycelial envelope. In other respects 

 they resemble those of Apterostigma and are grown on the same substrata. 

 The heads are developed as long, irregular swellings in the hyphae and 

 therefore represent a more primitive and imperfect stage than those of 

 Acromyrme.v. Although he was unable to obtain the fruiting stage, INIoeller 

 nevertheless believed that the fungus of the species of Cyphomyrmex is 

 different from that cultivated by the ants of other genera. He concludes 

 his paper Avith a few interesting notes on the breeding habits of the Attii. 

 The eggs of Acromyrmex are laid in masses and embedded in loosely woven 

 hyphfe which enable the ants to carry them about in packets. The pupae, 

 too, are often enclosed in hyphee, but this is not the case with the larvfe which 

 are kept clean and shining. 



In 1894 von Ihering, in an interesting paper on the ants of Rio Grande do 

 Sul, records a number of observations on Attii {Atta sexdens, Mcellerius 

 striatus, Acromyrmex lundi, niger and Cyphomyrmex morschi). His general 

 account of the nests of A. .'ie.rde7}s agrees with that of preceding authors 

 who have studied the large Attfje s. str., and comprises also an interesting 

 observation cjuoted from a former paper (1882) on the importance of these 

 insects in reversing the position of earth strata: "A piece of pasture land 

 had been marked off by a recently excavated ditch several feet deep. The 

 soil in this place, as generally in the surrounding country, consisted of sand. 

 Beneath this in many portions of the region there was a stratum of heavy 

 red clay at a depth of four feet or more. What attracted my attention in 

 this ditch was the fact that here the clay lay uppermost in a layer about 1 dcm. 

 thick. The explanation of this condition was not the result of geological 



