No. 417.] NESTS OF AMERICAN ANTS. 721 
males and females of the parasitic species, but was also pro- 
vided with the winged sexes of the Monomorium. When both 
species were put together in the same vial the Epoecus queens 
attacked and killed some of the males of Monomorium. These 
meagre data constitute all the forthcoming evidence for sup- 
posing that the habits of Epoecus are analogous to those of 
Fic. 20. — Epæcus pergandei Emery (after Emery). æ., male; b., female. 
the European Anergates. I may add that I have examined 
many dozens of Monomorium minimum nests in Texas in the 
hope of finding their rare parasite, but up to the present time 
my search has been in vain. 
VII. SvNCLEROBIOSIS. 
The mixed nests of uncertain origin and significance are of 
considerable interest, but unfortunately they are very rare, and 
as their origin has never been observed in any single instance 
either in Europe or America, it is possible to do little more in 
the present state of our knowledge than to catalogue the dif- 
ferent cases. Mixed nests of this character are formed by the 
union of dominant species with unusual auxiliaries or vice 
versa, or by the close consociation of species which normally 
inhabit independent colonies. It is generally agreed that such 
nests must be either predatory unions, established after the 
manner of dulotic species by robbing the larvæ and pupæ of 
Species which never function as normal auxiliaries, or by alli- 
ances between queens of different species before or soon after 
Starting their colonies. . Experiment may be expected to throw 
