160 HYMENOPTERA. 



duals outside the column, these occasionally ran rearward a short 

 distance, and then again advanced in the direction of the main 

 body : these means were apparently for the purpose of keeping up 

 a current of intelligence along the line. In fact when I disturbed 

 the column, or abstracted an individual, intelligence of the dis- 

 turbance was very rapidly communicated several yards backwards, 

 and the column at that point commenced retreating. The pro- 

 cession was not a predatory affair, because all the small-headed 

 individuals conveyed in their mandibles a little cluster of white 

 maggots, probably larvaj of their own s])ecies. I have no doubt 

 of its being a migration, as at the time of observation a change 

 of season was taking place, the river retreating from the beach, 

 and the open places above, about to be burnt up by the hot sun 

 of the dry season. 



"The large-headed individuals were in ])roj)ortion of perhaps 

 about five in one hundred to the small individuals, but not one 

 of them carried anything in its mandibles; they were all trotting 

 along outside the column, and distributed in regidar pro])ortion 

 throughout the whole line of army, their globular white heads 

 rendering them very conspicuous among the rest, bobbing up 

 and down as they traversed the inequalities of the road. 



" The progress of these ants is not in one simple line when on 

 a foraging expedition, but a line with many branches; a column 

 is occasionally pushed out in the direction of some promising 

 locality. I once observed one of these terminating at a decayed 

 fallen tree ; the ants were busy about it, a few having seized some 

 large Formicida, and also some soft-bodied wasps, these they 

 tore in pieces, and divided the load; the whole column then 

 retired, and re-entered the main line. A branch column is not a 

 party separated from the rest — there is no break in the lines of 

 these ants — but there is always a number passing and repassing, 

 keeping up the line of communication. 



" I lately discovered what I imagined was a formicarium of an 

 Eciton : I traced a procession in which many were carrying ova, 

 larvfe, and pupre ; at a short distance I found the column termi- 

 nating abruptly, not as I expected at a vast earthy dome, but at 

 a heap of dead leaves in a hard trodden pathway ; on the leaves 

 were mustered an unusual nimiber of the laige-headed indi- 

 viduals, who resisted^my disturbing the leaves with great ferocity. 

 I found under the leaves a large . collection of ova, pupa;, and 

 , larvae, all apparently of one species, certaiidy a Myrinicide, as 

 the pupai were not enclosed in cocoons; the small-headed 

 workers rapidly gathered up the whole, and a great number of 

 others soon came up, including many of the large-headed fellows, 

 and attacked me most furiously ; it was no doubt a temporary 

 store made during a predatory expedition." 



