8 ADELE M. FIELDE. 



vamcns, Camponotus pictus, Camponotus americanus, Lasius 

 latipes, and Lasius umbratns, and all these males have invariably 

 been killed within a day or two. If hybridization is to be 

 effected among ants it will be necessary to cause the males and 

 females to become acquainted with one another within a few hours 

 after hatching. When hatched in the same nest, males of Sten- 

 ammafiilvum pursue queens of Cremastogaster liucolata with the 

 same ardor that they show in pursuing queens of their own 

 species. In my mixed nests the failure of individuals of these 

 two genera to mate was manifestly due to physical and not to 

 psychic incompatibility. 



In the summer of 1905 I had material in my stock of ants for 

 experiments giving evidence that the male ant has at hatching 

 the specific odor of his virgin worker-mother. My E mixed 

 nest consisted of workers of Cainponotus pictus, Formica ncoga- 

 gates, Formica subscricea, and Stcnanima fulvinn, all hatched 

 during the last week of July, 1904, and kept in the same nest 

 until the first day of January, 1905, when the Stenammas were 

 segregated apart. They remained in segregation until August 

 22, 1905, when I put into their small nest, where there were ten 

 workers and a few eggs, a fine male Camponotus pictus, the 

 offspring of a virgin worker-mother who had shared the nest of 

 these Stenammas until she was five months old. This young 

 male was received by the resident Stenammas with evident pleas- 

 ure. They licked him, regurgitated food to him, and rode on his 

 back. He continued to live happily with them for many days. 

 He bore a familiar specific odor, although hatched among segre- 

 gated workers of his species, eight months older than any that 

 these Sfenammas had known ; and this familiar odor made him 

 welcome. His fate was in strong contrast to that of some of his 

 brothers or cousins introduced into another nest. At the time 

 of these experiments I had also a nest, marked D, of eleven 

 Stenamma fuhnun workers, that had hatched in a mixed nest 

 during the last half of August, 1903, and had lived for several 

 months with Camponotus pennsylvanicns, and Formica subsericea, 

 but had never met a Camponotus pictns. These eleven Stenammas 

 had lived in segregation since July 17, 1904, and were destitute 

 of young, when on August 22, 1905, I introduced into their nest 



