Eciton legionis, Smith, Frederick, 1855

Smith, Frederick, 1855, Descriptions of some species of Brazilian ants belonging to the genera Pseudomyrma, Eciton and Myrmica (with observations on their economy by Mr. H. W. Bates), Transactions of the Entomological Society of London (2) 3, pp. 156-169 : 164-166

Sp. 7. Eciton legionis , n. s.

Worker.-Length 3 lines. Reddish yellow and shining ; antennae the length of the head and thorax, inserted in a lar^e cavity in front of the head ; the margins of the cavity raised in front, curving inwards round each scapus and passing upwards to the edge of the cavity: the head elongate ovate, slightly emarginate behind, the angles not produced ; the eyes very minute. Thorax narrower than the head, compressed at the sides, and rugose above ; the metathorax without carinae or spines; the nodes of the abdomen unarmed beneath : abdomen ovate, very smooth and shining.

Worker (minor). - 2 lines. Excepting in size I can detect no very distinctive difference from the large worker.

Of this species Mr. Bates observes, " I have only found it in open sandy and grassy campos; it shows the same irritability and hurried movement as the other species ; is very quick to break line, and to attack furiously, any intruding obstacle. In a procession which 1 observed there were no individuals with the largely developed mandibles, as in other species. The locality in which 1 observed it being an open district, it afforded me an opportunity of observing some parts of its habits, and the business which occupies its immense processions ; tlic columns of the other species I have always observed marching in the dense thorny thickets of the forest, so that the same facilities for observation do not offer themselves, and no human endurance can sustain the overwhelming attacks, the cruel sting and bite of these formidable insects. In this smaller species, although they climb by hundreds over one’s person, in the same sudden way, the sting is not at all formidable. The first time I met with this species, it was near sunset : I found the column consisted of two trains of ants, moving in opposite directions ; one train empty handed, the other laden with a variety of the mangled remains of insects, chiefly however the larvae and pupae of ants. I had no difficulty in tracing the line to the spot from which they were conveying their prey ; this was in a low thicket, the Ecitons were moving rapidly about a heap of dead leaves; the tropical twi light was deepening, and I deferred further examination till the next day.

" On the following morning I found no trace of the ants in the place I had left them the preceding day, nor in the thicket were there any signs of insects of any description : but, at the distance of eighty or one hundred yards, 1 found them again, eviden tly engaged on another piece of business, a razzia of a similar kind, but requiring other resources of their instinct; they were eagerly occupied on the face of an inclined bank of light earth, excavating mines, whence, from the depth of eight or ten inches, they were extracting the bodies of a bulky species of Formica . It was curious to see them crowding round the orifices of the mines, and assisting their comrades to lift out the bodies of the Formicae; the latter, being too bulky for one Eciton to carry, it was torn into pieces, and the laden marauders forthwith started off with their booty. On excavating the earth about the mines, I found the Formicae at the depth of about eight inches, also their larvae and pupae. As fast as I excavated, the Ecitons rushed in, seizing the ants ; I had great difficulty in securing a few specimens, they disputed them with me even in my hands : in excavating their mines, they assisted one another in so systematic a manner, with an appearance of so much intelligent co-operation, that it was truly a wonderful sight : those in the mines lifted up the pellets of earth to others stationed at the entrance, who forthwith conveyed them to a few inches distance from the place.

" I now turned towards the line of ants returning with their spoil of mutilated remains. For some distance there were many lines of them moving along the declivity of the bank, but at a short distance these converged ; I then traced them to a large indurated and ancient Termitarium : up the ascent of this the Ecitons were moving in a dense column, like a stream of liquid metal ; many were now assisting in lugging up the bodies of the Formicce, and the whole disappeared in one of the spacious tubular cavities which always traverse these old Termitaria from the summit to the base.

" It would appear, from what I observed, that Eciton feeds its larvae with animal food ; the species of Formicae seized by this species of Eciton has a soft succulent body, and, if not intended as food for the larva, for what other purpose are they procured ? probably, like the leaves gathered by Oecodoma , they pass through a process of comminution, before being supplied to the larvae."

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