18*79.] NATURAL SCIENCES OF PHILADELPHIA. 37 



bery. He had to be very careful thereafter where he deposited 

 the delectable weed. Mr. McCook saw at another plantation an 

 immense column engaged in plundering a granary of wheat, which 

 was being carried away to the nest. 



4. Interior Architecture. The use of this leaf material, in part 

 at least, was unfolded when the work of excavation began. Two 

 trenches were made, one ten feet long, five feet deep, and a second 

 at right angles to it, and wide enough to allow free entrance and 

 study. The number of insects that swarmed to the defence of 

 their home is simply amazing. They were, however, not so diffi- 

 cult to manage as sometimes when disturbed at their night work, 

 as the swift use of the spade by the assistants and the general 

 convulsion of their emmet world quite dazed most of them. 

 However, when the speaker himself entered the trend) to work 

 with trowel, knife, rule, etc., the ants rallied, and attacked so 

 fiercely that the men were compelled to brush them off. The 

 wound inflicted by them was sharp, but nothing to compare with 

 the severe sting of the agricultural ant. The interior of the for- 

 micary may be briefly described as an irregular arrangement of 

 caverns communicating with the surface and with each other by 

 tubular galleries. These caverns or pockets were of various sizes, 

 2 feet 10 inches long and less, and 12 inches deep and 8 inches 

 high and less. Within these chambers w r ere masses of a very 

 light, delicate leaf-paper wrought into what may properly be 

 called " combs." Some of the masses were in a single hemisphere, 

 filling the central part of the cave, others were arranged in colum- 

 nar masses 2\ inches high, in contact along the floor. Some of 

 these columns hung, like a rude honey-comb or wasp nest, from 

 roots which interlaced the chamber. The material was in some 

 cases of a gray tint, in others of a leaf-brown. It was all evi- 

 dently composed of the fibre of leaves which had been reduced to 

 this form within the nest, probably by the joint action of the man- 

 dibles and salivary glands. On examination they proved to be 

 composed of cells of various sizes, irregular in shape, but main- 

 taining pretty constantly the hexagon. Some of the cells were 

 one-half inch in diameter, many one-fourth inch, most of them 

 one-eighth inch, and quite minute. Large circular openings ran 

 into the heart of the mass. Some of the cells were one inch deep ; 

 they usually narrowed into a funnel-like cylinder. Ants in great 

 number, chiefly of the small castes, were found within these cells. 

 In the first large cave opened were also great numbers of larva?. 

 The material was so fragile that it crumbled under even delicate 

 handling, but a few specimens of parts of the ant comb, with 

 entire cells, were preserved and exhibited. Reference was made 

 to the late Mr. Bell's opinion that these leaf paper masses were 

 used as a sort of u mushroom garden," a minute fungus being 

 purposely cultivated upon them, which the ants used for food. 

 Mr. McCook's specimens, when submitted to the microscope, did 



