THE ASSOCIATION OF ANTS WITH BUTTERFLY LARViE. 31 



flower- spikes as the larvae, and thought they were attracted by the 

 nectaries of the flowers, until he observed an ant running up and down 

 the back of one of the larvae, drumming and gesticulating with its 

 antennae, the feeding larva not at all disturbed by the treatment. 

 Three kinds of ants were observed, and, on one occasion, six examples of 

 a small ant were seen to be busy with one larva at the same time, but the 

 movements of all the species were similar. They run over the body, 

 caressing the larva incessantly with the antennae, and undoubtedly 

 with the object of persuading it to emit the fluid. Much of the 

 caressing is done about the anterior segments, and, while the ants are 

 absent from the posterior segments, the tubes (on the 8th abdominal) 

 are almost constantly exposed to their full extent, and so remain, 

 without contracting, until the ants come tumbling along in great 

 excitement, and put either foot or antenna directly upon, or close by, 

 the tubes, when these are instantly withdrawn. The ants pay no 

 heed to these tubes, so far as touching them with intention, but at once 

 turn to the median gland, caress the back of the 7th abdominal 

 segment, put their mouths to the orifice, and show every sign of eager 

 expectancy. With a lens, a movement will speedily be apparent, a 

 dark green mammilloid membrane will protrude, from the top of which 

 exudes a tiny drop of clear green fluid. This the ants drink greedily, 

 two or three of them perhaps standing guard over it. The demonstra- 

 tions of the ants are of the most gentle nature, caressing, entreating ; 

 and, as the little creatures drink the fluid, they lift their heads as if to 

 prolong the swallowing. There is a manifest satisfaction and delecta- 

 tion that is amusing to see ; they lick away the last trace and stroke 

 the back of the segment, and wait to see if their coaxing avails 

 anything ; if not, they run about, but presently all return and the 

 caressings go on as before. The intervals between the appearance of 

 the globule vary with the conditions of the larva ; if exhausted, by 

 yielding to the frequent solicitations, some minutes may elapse, and 

 the tubes, meanwhile, will remain concealed ; but a fresh larva 

 requires little urging, and the mere intimation of the presence of an 

 ant in the vicinity is enough to cause the tubes to play rapidly, and 

 one globule to follow another, sometimes without a retracting of the 

 membrane and before the near approach of the ants ; six emissions 

 were once counted in 75 seconds. The tubes are usually expanded 

 when the ants are away from the posterior segments, and are retracted 

 when they come near ; counting the length of these periods of complete 

 and quiet expansion, they were found to be 10, 20, 50, up to 80, 

 seconds, the period always ending with the approach of the ants. 

 Experiment, by placing larvae upon stems of the growing plants where 

 the ants had access to them, showed that, as soon as the ants 

 discovered one of them, there was an immense excitement and a rush 

 for the hinder larval segments ; the larva forthwith relieved itself by 

 the excretion of the fluid, and the tubes stood out with tops expanded 

 between the periods. A larva, placed on a stem on which there were 

 no ants, showed no excitement, no appearance of the tubes, and no 

 movement of the median glands ; if ants were transferred to the 

 stem, the larva at once changed its behaviour. Scudder adds that, it is 

 only in the later stages that the ants attend the caterpillars, or any fluid is 

 excreted from the median gland, though the organs are certainly present 

 at an earlier stage. Edwards further finds the attendance of the 



