174 
BUMBLEBEES 
Pig. 5 .—Bombus americanorum; a, queen; b, worker. (After Sladen.) 
Pig. tS .—Bombus fervidus; a, male; b, queen; c, worker. (After Sladen.) 
Fig. 7 .—Bvmbus impatiens; a, male, b, queen; c, worker. (After Sladen.) 
Fig. 8 .—Psithyrw laboriosus; a, queen; b, male. (After Sladen.) 
