236 Psyche [December 
Viereck has described from New Mexico a new subspecies as 
subumbratus, and another subspecies, vestitus, from Idaho, is 
added in the present paper. This form may prove to be the 
hitherto unknown female of Emery’s L. speculiventris, which, I 
believe, is merely a subspecies of umbratus. 
All the various forms that constitute the species wmbratus may 
be readily distinguished in the worker and female phases from 
the other species of Lasius, by the following peculiarities: the 
maxillary palpi are 6-jointed and this character places the species 
in the genus Lasius sensu stricto and removes it from the exclu- 
sively North American subgenus Acanthomyops, which includes 
species with 3-jointed maxillary palpi and a strong odor like that 
of lemon verbena or oil of citronella. The joints of the maxillary 
palpi in wmbratus are not long and subequal as in L. niger and 
its various forms, but grow successively shorter towards the tip. 
It differs from our two other Lasvi with yellow workers and dimin- 
ishing maxillary joints (L. flavus nearcticus Wheeler and L. brev- 
icornis Emery) in having the antennal scapes extending a consid- 
erable distance beyond the posterior corners of the head, the 
larger size of the eyes in the worker, and in being more or less 
tinged with brown in this phase. Moreover, the female wmbratus 
has the head as broad as the thorax, whereas in nearcticus and 
brevicornis it is distinctly narrower. It is by no means easy to 
separate the various subspecies or races of wumbratus on morpholog- 
ical characters, such as the size of the eyes of the worker, shape of 
the petiole of the worker and female, dentition of the mandibles 
of the male, etc., since these characters are rather inconstant. 
More satisfactory distinctions are furnished by peculiarities of 
stature, pubescence, pilosity and color. 
Notwithstanding its wide distribution LZ. wmbratus is by no 
means as common as other species of the genus. In North America 
however, it is much more frequently met with than in Eurasia; 
but even in our country it is sporadic, being abundant in certain 
localities and totally lacking in others. It prefers rather damp, 
shady spots like those occupied by L. nearcticus and the species of 
Acanthomyops. Like the species of this sub-genus it forms populous 
colonies under stones, in rotten stumps or logs or constructs large 
masonry dome nests. These dome nests I have seen only in 
meadows or in clearings in the woods where the soil is covered 
