1879.] NATURAL SCIENCES OF PHILADELPHIA. 35 



every exit from the nest. The process is a long, careful, and 

 complicated one, and was studied folly'. Towards evening the 

 gates are gradually thrown open, and so remain until morning, 

 when they are gradually closed, the process continuing in some 

 cases until 10^ A. M. The closing is done by carrying into the 

 gallery bits of dry twigs of various lengths, some as long as H 

 inch, dry leaves, and other refuse. A number of closed gates 

 were opened to note the depth to which this refuse was placed. 

 It varied from one-half inch to an inch and a half from the sur- 

 face. In some cases the gallery had been sealed up with sand 

 pellets below the refuse. The galleries quite often slant inward 

 from the gate, and at as great an angle as 45. They also some- 

 times divide a short distance from the surface. These conforma- 

 tions allow more readily the process of closing. In carrying in 

 the refuse the larger forms of the ant are engaged ; as the hole 

 gradually closes, only the very smallest appear. The last touches 

 are carefully and delicately made by the minims, who, in small 

 squads, fill in the remaining interstices with minute grains of sand, 

 and finally, the last laborer steals in behind some bit of leaf, and 

 the gate is closed. It then presents to the causual observer the 

 appearance above described of a little heap of dry chips acci- 

 dentally accumulated upon the mound. The galleries at Camp 

 Jeanes were closed in the same manner. 



When the gates are opened at dusk, this process is reversed. 

 The minims first appear, deporting from the heap particles of 

 sand. Larger forms follow, carrying away bits of refuse, winch 

 they drop a couple of inches more or less from the gate. This is 

 a slow process, and apparently little is accomplished for a long 

 time. But evidently the whole mass of refuse is thus loosened. 

 Then comes the final burst, with soldiers, majors, and minors in < 

 the lead, who rush out bearing up before them the rubbish, which 

 flies here and there, and in a few moments is cleared away from 

 the gallery, and spread around the margin of the gate. These 

 chips are evidently gathered together for this purpose, and are 

 among the " treasures" of the ants, being kept near by for this 

 use. The pieces were easily identified as being thus used several 

 days in succession. 



The above observation points out at least the use found for the 

 extremely small forms peculiar to this species. At least ten dis- 

 tinct castes (forms or sizes) were exhibited to the Academy. 

 They vary as follows, the measurements being in sixteenths of an 

 inch, viz., ?, 14 ; % , 11 ; soldier 7 ; worker major 6 ; minor 5 ; and 

 the remaining castes in the proportion, 3|, 3, 2^, 2, 1^, 1. A 

 more careful comparison may possiblj- reduce this series one or 

 two. But the result, as above, will probably stand. 



The gates first opened are the first closed, and those last opened 

 are the last closed. 



3. Leaf -cutting Habit. The whole process of cutting and car- 



