RESEARCH SEMINAR. 309 



July 17. Effects of Light-rays on an Ant. By ADELE M. 



FlELDE. 



The species used for the experiment was Stcnainina fnkmui, a 

 myrmicid ant. Five queens and about two hundred workers 

 were kept for ten months in each of five artificial nests, one nest 

 roofed with transparent glass, one with opaque glass, one with 

 glass transmitting only red and green rays, and two with glass 

 transmitting only rays of shorter wave-length than blue. These 

 nests were exposed to like temperature, and the ants were fed on 

 the same foods. In all the nests the young passed safely through 

 the egg, the larval and k the pupal stage, and reached active life, 

 proving that the cause of the usual hasty withdrawal of the 

 inert young from daylight does not lie in any injury by any of the 

 rays of the spectrum. 



The ants are blind to all rays of light other than the ultra-vio- 

 let, and they avoid the ultra-violet rays in proportion to the in- 

 tensity of the illumination. They often congregated with their 

 young in the spots where the illumination from the red and green 

 rays was most intense. Orange glass which excludes most of 

 the ultra-violet rays may be used for roofing their artificial nests, 

 and then the ants may be studied with the certainty that they be- 

 have as if they were in darkness. 



At the end of ten months marked ants from each of the five 

 nests were introduced into each of the other four nests, where they 

 were amicably received, and it was thus determined that exposure 

 to any ray of light in the spectrum does not affect the odor 

 whereby the ants recognize one another. 



July 20. Further Experiments in the Embryology of the 



Chick. By F. R. LILLIE. 



First, three cases in which the cerebral hemisphere of the right 

 side was destroyed at an early stage, and which resulted, after 

 farther growth of the embryo for four or five days, in displace- 

 ment of the wing rudiments of the opposite side. This displace- 

 ment was the same in all cases and was never found in normal 

 embryos. The conclusion was that there is some trophic relation 

 between the higher brain centers of one side and the embryonic 

 tissues, especially muscular tissues, of the opposite side; this be- 





