168 Psyche [December 
abundant form of wmbratus. The subspecies speculiventris and 
vestitus are imperfectly known, the latter from a single female 
specimen, the former only from the types taken many years ago 
by Pergande at Caldwell, N. J. The subspecies minutus is very 
sporadic. During the past eight years I have found only a single 
colony of it in the vicinity of Boston. The types of the sub- 
species subumbratus were taken by Professor Cockerell at Beulah, 
N. M. (alt. 8,000 ft.). I have taken it at Williams, and on Mt. 
Lemmon in the Santa Catalina Range (9,000 ft.), Ariz., at Cloud- 
croft, N. M. (9,000 ft.), Lake Tahoe, Calif. (8,000 ft.), near Ottawa, 
Ontario, and Hull, Quebec and have seen specimens from Digby and 
Bedford, Nova Scotia. It is therefore the most boreal and steno- 
thermal of all the North American subspecies of wmbratus and, as I 
have stated in a former paper (1917), properly belongs to the 
Canadian zone. 
To the ethologist wmbratus is of unusual interest, because in 
Europe it is a temporary parasite of LZ. niger and in turn serves as 
the host of L. (Dendrolasius) fuliginosus, which is therefore a true 
temporary social hyperparasite. The young wmbratus queen is 
adopted by a colony of niger workers, which bring up her brood. 
Eventually these workers die off, probably in the course of four or 
five years, and the wmbratus colony, now pure, becomes very 
populous. Then it may in turn adopt a queen of fuliginosus, the 
offspring of which eventually supplant the wmbratus colony. In 
both cases the host queens are eliminated, probably by being 
assassinated either by their own workers or by the parasitic 
queens. The various phases in the development of the umbratus 
and fuliginosus colonies have been studied by European myrme- 
cologists. The occasional occurrence of mixed colonies of um-, 
bratus and niger and umbratus and fuliginosus was noted by 
Schenck, Adlerz, Forel, Wasmann and de Lannoy, but Emery and 
Forel in 1908 first suggested that they might be interpreted as 
arising from temporary social parasitism. Later Crawley and 
Donisthorpe fully demonstrated the truth of this conjecture by 
showing that the typical wmbratus is parasitic on the typical 
niger, the subspecies mizxtus on the subspecies alienus, and that 
umbratus regularly functions as the temporary host of fuliginosus. 
Although North America is so rich in wmbratus forms, no one has 
hitherto been able to prove from observations in the field that any 
