MANN: THE ANTS OF BRAZIL. 419 



46. Odontomachus haematoda subsp. imbescens Roger. 



Very common at Ceara, in the Maranguape Mts., Independencia, 

 Natal, and Ceara-Mirim. This form is distinguished from the typical 

 0. haematoda by the more abundant pile and pubescence, and by the 

 coarser sculpture of the node, which is only feebly striate in the latter 

 form. 



47. Odontomachus haematoda subsp. laticeps Roger. 



Porto Velho and Camp 41, Madeira-Mamore R. R. 

 This was much rarer than the above mentioned forms. 



DORYLINAE. 



48. Eciton {Eciton) hamatiim (Fabricius). 



This species, which ranges from Mexico through Central America 

 and over all of tropical South America, was very abundant in the region 

 of the upper Rio Madeira. The armies, found in the woods almost 

 every day, contained enormous numbers of individuals, mostly minors 

 and mediae. One of the big-headed soldiers was encountered at 

 intervals of from ten to twenty feet in the procession. This form is a 

 very conspicuous object on account of its large, light-colored head and 

 the long mandibles which necessitate the body being held high. 



The march of the army is exceedingly rapid, and at times very 

 definite in direction. Often it divides and sends some branches up 

 into the tallest trees, while others cross and recross the trails. If an 

 object such as a grub, lizard, or small snake be thrown near the column, 

 it is almost instantly covered with the workers, which bite and sting 

 severely. Unlike some of the other species, E. hamatuvi marches in 

 the daytime and the column travels beneath or over the leaves, over 

 logs, and along the trails. The trunks of fallen trees are a favorite 

 runway. Other species of ants seem to be the usual prey of E. hama- 

 tum, for larvae and pupae of these made up the greater part of the 

 booty carried by the workers. I observed on several occasions 

 columns descending trees bringing numbers of larvae, pupae, and even 

 adults of Dolichoderus lugens Emery, an ant which secretes from the 

 anal glands a large drop of yellow liquid, apparently for defense. 



In spite of its large size and the number of individuals in a column, 

 E. hamatum is a timid species in comparison with some of the others, 

 such as E. Taga7is. When the column was disturbed by my picking 



