106 
Psyche 
[December 
Although no discussion of the arguments on both sides 1 
will be attempted, it should be noted that no amount of 
experimental manipulation of environmental conditions has 
succeeded in producing morphological intergrades between 
queen and worker — only smaller queens and larger workers. 
Species do vary considerably, however, in the degree of 
variation transitional between the two castes, but always 
there is a distinct hiatus. Under natural conditions, each 
species normally has a certain season of the year, usually 
Spring or Fall, during which a portion of the female brood 
develops into queens. Further, it has been noted by num- 
erous observers that the proportion of queens and workers 
produced at such times varies widely and shows a strong 
correlation with the economic conditions of the colony: 
the weaker and less well-nourished the colony, the smaller 
the proportion of queens and males produced. Obviously, 
there is some method by which the colony controls the time 
of appearance, number and proportion of the different castes. 
In the past, practically every approach to the problem has 
consisted in marshalling general truths, analogies, bits of 
evidence in the way of field observations and anomalous 
specimens, and logical sequences by the proponents of one 
side or the other in support of their theory. For example, in 
the most recent of such engagements, Wheeler (1937), after 
careful study of a remarkable series of what were appar- 
ently queen- worker mosaics of the ant Acromyrmex octos- 
pinosus, came to the conclusion that the female castes are 
determined blastogenetically. Whiting, (1938), reviewing 
Wheeler’s book, showed that these same mosaics could be 
intercastes and explained equally well on a trophogenic basis. 
Thus the solution is left as inconclusive as before, and it is 
apparent that only controlled methods of approach can 
decide. The only previous experimental approach to the 
problem which I have been able to find appears to be that 
of Ezhikov (1934) who writes: “When we subjected to 
hunger the larvae of ants destined to be females (Campono- 
tus, Myrmica) at different moments of their development, 
we never were able to obtain forms transitional between 
the queen ant and the worker, but either real fertile females, 
1 Dr. Wheeler’s book (1937) contains something of the various argu- 
ments, together with an extensive bibliography on the subject. 
