79 



PIG 



Fig. 31. Milkweed. PoUinia of ^sctepias cor»uti; 1. flower as seen from the 

 side; 3. cross section of flowers; 4, polllnia; 5, foot of insect with pollinia. 

 (After Eeraer von Marilaun.) 



FIG. 32. 



Fig. 32. Bumble bee (Bomfttts Scutellaria Cress) with pollinia from milkweed 

 lAeerates lonaifoHa)r (After Charles Kobertson.) 



