294 Margaret Hollida y, 



that tliose characteristics that distinguish the typical worker front 

 the ([ueeii are partl}' of a retrogressive nature, for exainple tlie 

 reductiou of the receptaculum seminis, ovaries, eyes, wing's, togetlier 

 with tlieir muscles aiid muscular attachments, and partly progressive, 

 for example the increased size of maiidibles and their mnscles. . . ." 

 Gradually these morphological distinguishing characteristics have 

 been rendered more and moi-e useless as perfectly sure factors for 

 purposes of Classification. The value of the wings was lessened when 

 ergatoid females. without even any traces of the wing sutures were 

 discovered; then queens and workers were found with similar 

 thoracic strnctnre, and thus we see the distingnishing factor has been 

 pushed gradually back to the organ in the individual most important 

 phylogenetically, the reprodnctive organ. The male, of course, can 

 thus be distinguished readily, and the Separation of the queen and 

 worker has been based flnally on the condition of the ovaries as the 

 determining factor. 



Exact knowledge of the morphological and physiological coudi- 

 tions of the ovaries of ants is still somewhat meager, and it seenis 

 to be accepted as a fact that the ovaries of worker ants are more 

 or less rudimentary organs, sometimes to the point of complete 

 sterilit3^ possessing fewer tubules than those of the queen. Without 

 doubt this is the condition in some species. The work of Wasmaxx 

 and Miss Bickford shows that morphologically, in some ants at least. 

 there is no reason why workers in natural conditions should not 

 produce eggs, and indeed Adlerz says in liis summary. "We know 

 that the workers of most ants may lay eggs capable of development, 

 and that their ovaries thus, in spite of reduction in the number of 

 tubules, cannot be considered as rudimentary, if by this term we 

 mean not only lack but also decrease of function." The question 

 then is a physiological one: do they produce eggs capable of deve- 

 lopment ? 



When the condition of the ovaries was taken as a distinguishing 

 characteristic between the queen and worker, the receptaculum 

 seminis was immediately thought to be the surest means for de- 

 termining the functioning power of the ovaries, and Adlerz declares: 

 "C'est par la presence de receptaculum seminis que certains individues 

 prouvent leur capacite ä remplir les fonctions d'une femelle, et les 

 veritables femelies de cette espece." Thus according to this State- 

 ment all ants possessing the receptaculum seminis must be 



