32904: 
igs bas 
VOL. XXIV DECEMBER, 1917 No. 6 
THE TEMPORARY SOCIAL PARASITISM OF LASIUS 
SUBUMBRATUS VIERECK.! 
By Wiiu1am Morton WHEELER. 
During the past summer, while studying the ants of the Sacra- 
mento Mountains, at Cloudcroft, N. M. (alt. 9,000 ft.), I had an 
opportunity to observe the method of colony formation employed 
by Lasius (Formicina) umbratus Nyl. subsp. subumbratus Viereck. 
L. umbratus has long been known as a circumpolar species compris- 
ing several races, or subspecies and varieties, the names and known 
geographical distribution of which are recorded in the following 
list: 
Pavearctic Forms. 
L. umbratus subsp. umbratus Nyl. Northern and Alpine Eu- 
subsp. miztus Nyl. rasia from Britain to 
var. mixto-umbratus Forel Japan. 
var. umbrato-affinis Ruzsky Russia. 
Nearctic Forms. 
subsp. mixtus var. aphidicola Walsh Canada, Central and At- 
lantic States. 
subsp. subumbratus Viereck British America, Rocky 
Mts. 
subsp. speculiventris Emery Known only from New 
Jersey. 
subsp. vestitus Wheeler Known only from Idaho. 
subsp. minutus Emery Central and _ Atlantic 
States. 
In Europe, according to Wasmann and Donisthorpe, the var. 
mixto-umbratus 1s more common than the typical wmbratus or 
mixtus, between which it is intermediate in size, color and pilosity. 
In the Eastern United States aphidicola is certainly the most 
1 Contributions from the Entomological Laboratory of the Bussey Institution, Harvard 
University. No. 136. 
