Sept., 1908.] Burrill : A Slave-making Foray. 14 7 



ing Aphcsnogaster fulva and lighter colored — black abdomen and a 

 lighter red-brown head and thorax — but considerably smaller than 

 the black, slave ant, Formica fusca var. subsericea, and slenderer.* 



Perhaps the most interesting part of the foray was the return of 

 the army to the home nest. At 2:55 p. m., the slaves, of a species 

 like that captured, were excitedly and swiftly bringing out excavated 

 earth at the home nest, while two or three amazons ran slowly about 

 among them. Thus not all the soldiers of a nest go on a given foray. 



The returning train of Polyergus became slightly mixed up in cross- 

 ing the wagon road ; the ants starting exactly NE, thus getting off the 

 trail which angled to the right at that crossing, then returning nearly 

 to the edge of the road where they started to cross, taking an ESE 

 course which soon intersected the trail they sought. Having crossed 

 at last they seemed to get off the trail again and beat about until into 

 a NE direction. The succeeding ants gradually straightened out the 

 trail till it led directly across the road and then on NE, evidently the 

 way they had first traversed that bit of country. But there continued 

 to be a slight confusion at the turn of the trail to cross the road. It 

 occurred to me later that a wagon may have crossed this trail between 

 the crossings of the in- and outgoing trips, which would of course 

 obliterate the scent at the shallow wagon ruts. On the other hand, the 

 sanguineus often get mixed up at the angles or turnsthey sometimes make 

 in their trails. It seems as if this pointed to the probable limitations 

 connected with a scented trail, for the ants seem to get a general direc- 

 tion in mind despite their little twists and turns to avoid obstacles 

 and do not quickly appreciate a turn in the trail. The only refutation 

 of this that I can think of is that the first ants that scented the trail may 

 have faltered here in their direct advance and thus caused confusion to 

 all succeeding individuals, — another possible limitation to the scent 

 method of trailing. 



After the trouble of finding the place to cross the road, there were 

 two amazons with young ants in their jaws that kept in the lead by 

 about two or four feet all the way. One of them ran straight into the 

 nest entrance and the other ran shy about four inches to the NE of it 

 before she quickly oriented herself and also quickly disappeared down 

 the hole. Apparently not until four or five had arrived did the news of 

 the success of the expedition spread. Thus it does not always happen 



*The ant referred to by Mr. Burrill was evidently Formica schauffussi Mayr, 

 which is the normal slave of lucidus. — EDITOR. 



