PSYCHE 
VOL. XXIX. OCTOBER-DECEMBER 1922 Nos. 5-6 
NOTES ON THE NESTING HABITS OF SEVERAL NORTH 
AMERICAN BUMBLEBEES. 1 
By O. E. Plath. 
Massachusetts Institute of Technology, Cambridge, Mass. 
In a comprehensive paper on the bumblebees of Central 
Europe, Friese and Wagner (1910, p. 69) make the following 
statement: “Insbesondere liisst die Kenntniss der Nester noch 
allzuviel zu wtinschen iibrig, was um so empfindlicher ins Ge- 
wicht fallt, als geracle von clieser Seite her die vielleicht wertvoll- 
sten Aufschliisse zu erwarten stehen, weil alien Folgerungen, die 
lediglich auf einem durch Fang der frei fliegenden Tiere gewon- 
nenen Materiale basieren, notwendigerweise eine gewisse 
Unsicherheit anhaften muss.” The truth of this statement has 
been amply proved by the work of Drewsen and Schiodte (1838), 
Smith (1876), Schmiedeknecht (1878), Hoffer (1881, 1882/83, 
1885, 1888), Coville (1890), Sladen (1899, 1912, 1915), and 
Frison (1916, 1917, 1918, 1921). 
What Friese and Wagner (p. 69) have to say concerning 
the Central European bumblebees, is even more true of our 
American species. Of the 86 New World species of Bremus 
(Bombus) listed by Franklin (1912/13, 1914) and Frison (1921a), 
the nesting habits of only 17 have thus far been recorded, 2 but 
some of these data are so incomplete that they have little or no 
value. It is the object of this paper to add another species 
( Bremus occidentalis Greene) to those enumerated below and 
to supplement our knowledge concerning the nesting habits of 
iContribution from the Entomological Laboratory of the Bussey Institution, Harvard 
University, No. 211. 
2Those of Bremus affinis, auricomus, bimaculalus, borealis , cayennensis, emelice ( thor - 
acicus), fervidus, Jlavifrons, impaliens, pennsylvanicus, per plexus, rufocinctus, separalus, 
lernarius, lerricola, and vagans; by Putman (1865), Coville (1890), Hudson (1892), von Ihering 
1903), Franklin (1912/13), Howard (1918), and Frison (1916, 1917, 1918, 1921). 
