12 WHEELER. [VOL. II. 



when the mouth-parts are in the position represented in 

 Fig. i. The slender antennae, too, are carried in a peculiar 

 position, their tips being directed inwards. The touching of a 

 living insect or of any unfamiliar object with these incurved 

 tips calls forth a peculiar response, which seems to be largely 

 of a reflex nature. The ant darts forward and suddenly closes 

 its mandibles with a very audible click. The signal for closing 

 the mandibles seems to be given the moment the long sense- 

 hairs touch the object. The mandibles are brought together 

 with such force that if they strike a solid object the ant is 

 thrown backwards - - often to a distance of three or four inches 

 - occasionally even to a distance of ten or twelve inches. 

 The ant alights on its feet, like a cat, and again advances to 

 repeat the act. This remarkable clicking and leaping habit is 

 called into play on every occasion, and its study discloses some 

 interesting facts, as the following jottings from my notebook 

 will show : 



May 12. Placed a living house-fly in the Odontomachus nest. 

 Its movements at once attracted several ants, which began snap- 

 ping at it like a pack of angry dogs. With each snap a leg or 

 wing was severed and often thrown to a distance of 2 or 3 inches. 

 In less than a minute all the limbs had been shorn from the 

 trunk. The fly was then seized and decapitated. Next the 

 following living ants were placed in the nest in succession: 

 Eciton sumickrasti, Pogonomyrmex barbatus, and Leptogenys 

 clongata. The first and last were reduced to torsos as rapidly 

 as the fly ; the harder legs and antennae of the Pogonomyrmex 

 offered greater resistance, but not for long. The stings and 

 strong mandibles of these various ants were no protection 

 against the singular method of attack adopted by the Odonto- 

 machus. A smooth green caterpillar was next introduced into 

 the nest. It was at once surrounded and attacked by a dozen 

 ants. At first the ants retreated from the writhing larva after 

 each snapping of the mandibles, but soon they grew bolder and, 

 retaining their hold, drove their stings through its velvety 

 skin. One ant with a dexterous movement closed its mandi- 

 bles in the caterpillar's brain. In a few moments the green 

 blood of the victim was oozing from a score of wounds. 



