ZOOLOGY: W. M. WHEELER 
111 
simplification of thoracic structure (micronoty) so universal in the workers, 
is evidently a phylogenetic process, which was completed in most ant- 
genera before the Lower Oligocene. Aptery is, of course, to be care- 
fully distinguished from dedlation, the dropping of the wings by the 
female ant immediately after fecundation. Dealation is really a form 
of mutilation (autotomy) which has been practiced by female ants for 
millions of years without necessarily entaihng any modification or diminu- 
tion in the development of wing structures. Compared with this case 
of the non-inheritance of mutilations, the cases usually cited in the 
FIG. 1 
Winged, macronotal female of Monomorium rothsteini Forel var. humilius Forel, lateral 
view. 
text-books, such as circumcision and the docking of tails in mice, are 
insignificant, because they refer to such limated series of generations. 
There are a few genera of ants, especially in the subfamily Myrmi- 
cinae, in which it is possible to trace all the transitions in thoracic struc- 
ture from that of the female to that of the worker, except that, in all 
cases hitherto recorded, the wings show no transitions, but are per- 
fectly developed in the typical female and entirely lacking in all the 
other forms of the series. Good examples are certain species of Myrme- 
cina (M. graminicola) and Leptothorax {L. emersoni), but of all the genera 
