BUCKINGHAM. — DIVISION OF LAROR AMONG ANTS. 501 



potentially different, is distinguished from all the female forms in 

 structure and in those instincts which undergo development. 



VIII. Summary. 



The conclusions for certain parts of this paper have already been 

 given, and need only to be referred to here. Those on Polymorphism 

 have not been summarized ; they are stated for Camponotus on pp. 482- 

 438, for Pheidole on pp. 438-440 ; the summaries are to be found as 

 follows: Camponotus americanus (pp. 464, 465) ; Camponotus hercu- 

 leanus pictus (pp. 473, 474); Pheidole pilifera (pp. 488, 489); Pheidole 

 dentata (p. 490) ; Pheidole vinelandica (pp. 490, 491). 



In addition to these conclusions, certain other facts have been 

 established. 



1. Not only certain temperatures, but also increments of temperature 

 are an effective stimulus for ants. 



2. The fact that callow ants do not fight, may account for the possi- 

 bility of placing together young ants of different species to form mixed 

 colonies. 



3. Large ants are more apt to share in the work of a very small than 

 of a very large colony, showing in this respect a resemblance to the 

 queen. 



4. It is natural that the large workers and the soldiers should be 

 more sluggish in their activities and motions, since they more closely 

 resemble the queen than do the small workers. 



5. This sluggishness is a valuable adaptation, in that there are thus 

 always some ants which are not in an exhausted condition by reason 

 of constant labors, and therefore are ready to defend the colony. 



6. Inactivity is also advantageous in such forms as Colobopsis, 

 where guarding in one position for a long time would otherwise become 

 irksome, and more individuals would be required to perform this work. 



7. In Pheidole, where intermediate classes have probably dropped 

 out, the small ants perform all the duties which in Camponotus are 

 done by the small and intermediate workers together. 



8. The overlapping of the duties of the different classes of ants is 

 an additional reason for believing that the classes arise from eggs with 

 a similar potentiality. 



