366 ADELE M. FIELDE. 



posure to a temperature of 122 F. or 50 C. will kill the most 

 vigorous adult. 



FURTHER OBSERVATIONS ON ANTS DEPRIVED OF FOOD. 



Among the groups mentioned in my paper on "Tenacity of 

 Life in Ants" (in the BIOLOGICAL BULLETIN, Vol. VII., No. 6, 

 Nov., 1904, p. 300) were seven Formica subscricca workers that 

 had been deprived of food three months and remained alive at 

 the time of writing. These seven ants had been picked up from 

 a roadside where they were foraging under a linden tree, on July 

 3, 1904. They were kept in a Petri cell containing only them- 

 selves and a bit of sponge saturated with water. Cell and sponge 

 were cleansed with alcohol at intervals never exceeding four days, 

 until the end of September, after which time the cell and sponge 

 were cleansed only once a week. No growths were at any time 

 visible under a lens magnifying ten diameters. 



On February 3, 1905, one of these ants was removed for dis- 

 section, after an enforced fast of just seven months. One died 

 on November 27, one on November 29, 1904; one on February 

 17, one on February 19, one on March 14, and one on March 

 28, 1905, the latest survivor having lived nearly nine months 

 without food. 



A Camponotus Aincricanns worker, under like conditions, lived 

 without food from July 13, 1904, to February 12, 1905, just 

 seven months. 



Two sister queens, Camponotus Americanus, one dealated, one 

 winged, under the same conditions, lived without food from July 

 13 to December 6, 1904, both dying on the same day. These 

 queens had been bred in an artificial nest, and may have lacked 

 the stamina of untamed ants. 



After the first of October, all these fasting ants were kept at a 

 fairly steady temperature of 70 F. or 21 C. 



Until the day of death the ants walked about, reacted normally 

 to light and heat, and gave no evidence of failure in any of the 

 senses. 



In spite of the prolonged fast, there was no fighting nor can- 

 nibalism in any group of these ants, and the bodies of those that 

 had died were always found to be intact. 



