2Q2 ENTOMOLOGY 



recognize and spare members of their own colony, even after many 

 months of separation and though the colony may number half a million 

 individuals. This recognition is effected by means of an odor, dis- 

 tinctive of the colony and apparently inheritable. When an ant is 

 washed and then restored to its fellows, it is treated at first as an intru- 

 der and may even be killed. The same is true when the ant has been 

 smeared with juices from the bodies of alien ants. According to Miss 

 Fielde, workers of colony A, smeared with the juices from crushed ants 

 of colony B and then placed in colony B are received amicably, but at 

 once set about to destroy their hosts, like "wolves in sheep's clothing." 

 These statements apply only to workers, however, for alien larvae and 

 pupae are frequently captured and reared by ants, and Miss Fielde 

 states that kings of one colony of Stenamma when introduced into 

 another colony are even cordially received. 



Some of the most careful students of the habits of ants agree that 

 these insects can communicate with one another. An ant discovers a 

 supply of food, returns toward the nest, meets a fellow worker, the two 

 stroke antennae and then both start back to the food; before long other 

 members of the colony swarm to the prize. It has been thought that 

 the odor of the food or some other odor, left by the first ant, serves as a 

 trail for the other ants to follow. Bethe, indeed, infers from his ex- 

 periments that this phenomenon is purely mechanical and involves no 

 psychical qualities on the part of the ants. His own experiments, how- 

 ever, show that one ant can inform another by means of an odor as to 

 the whereabouts of food which is certainly one form of communication. 



Ants avoid sunlight as a rule but prefer rays of lower refrangi- 

 bility to those of higher. Upon exposing ants to the colors of the spec- 

 trum, as transmitted through glasses of different colors, Lubbock found 

 that they congregated in greatest numbers under the red glass and th^t 

 the numbers diminished regularly from the red to the violet end of the 

 spectrum, there being very few individuals under the violet glass. 



Miss Fielde, experimenting with queens, workers and young of 

 Stenamma fulvum piceum in an artificial nest, covered half the nest with 

 orange glass and half with violet. "The ants removed hastily from 

 under the violet as often as an interchange of the panes was made, once 

 or twice a day, for about twenty days. Thereafter they became indif- 

 ferent to the violet rays." "The plasticity of the ants is remarkably 

 shown in their gradually learning to stay where they were never disturbed 

 by me, under rays from which their instincts at first withdrew them." 



Ants are sensitive not only to the different colors of the spectrum 



