182 



HYMENOPTERA. 



direction along a fallen tree. I at length determined to trace the 

 procession through the jungle to their formicarium ; this I soon 

 discovered ; it was very different in appearance and much inferior 

 in size to the vast mounds thrown up by the species found at 

 Para and Santarem (E. cephalotes?}. The dome of the nest of 

 this species is only about a foot in diameter, and about the same 

 in height ; it is formed of light earth, matted and thatched as it 

 were with pieces of leaves which the workers cut and carry. I 

 watched the heavily-laden fellows as they came trooping in, and 

 found they all deposited their load in a heap close to the mound. 

 I then searched for the entrance to the interior ; I found, after 

 removing a little of the surface, three burrows, each about an 

 inch in diameter ; half a foot downwards all three united in one 

 tubular burrow, about four inches in diameter ; to the bottom of 

 this I could not reach when I probed with a stick to the depth 

 of four or five feet. The tube of the main burrow was perfectly 

 smooth, and covered with a vast number of workers of much 

 smaller size than those occupied in conveying the leaves: these 

 minute individuals were unmixed with any of the larger size. 

 Afterwards, on probing lower into the burrow, up came, one by 

 one, several gigantic fellows, out of all proportion larger than the 

 largest of those at work outside, and which I could not have 

 supposed to belong to the same species. Besides the greatly 

 enlarged size of the head, the sculpture of the body is very dif- 

 ferent, and what struck me as very curious, they have an ocellus 

 in the middle of the forehead ; this latter feature, added to their 

 startling appearance from the cavernous depths of the formi- 

 carium, gave them quite a Cyclopean character. There are, 

 however, individuals intermediate in size between these and the 

 other workers." 



An examination of the workers collected by Mr. Bates shows, 

 that although the smaller workers diifer in size, from two-tenths 

 of an inch to five-tenths, yet none of these have an ocellus in the 

 forehead, and the larger individuals having an ocellus scarcely 

 differ among themselves in size. 



The large worker of this species may be known from that of 

 (E. sexdentata, by having an ocellus, a more polished head, and by 

 having the mandibles of the same colour as the head, with the 

 teeth black ; (E. sexdentata has the anterior margin of the face 

 and the mandibles blackish-brown or black ; the colour of the 

 mandibles alone will serve to separate the small workers. 



2. (ECODOMA L^VIGATA. PL X. fig. 24. B.M. 



Worker major. Length 5-J- lines, Chestnut-red, nearly des- 

 titute of pubescence : the thorax, the two nodes, and the apical 



