154 JOHN H. LOVELL 



On June 11, 1912, a warm clear day, a honey-bee was observed 

 at 12:35 p. m., gathering pollen, also a wild bee which flew away 

 so quickly that it could not be determined. The honey-bee 

 visited four or five flowers before returning to the hive. A few 

 minutes later a second and third honey-bee came for pollen; 

 and during the succeeding hour one or two workers were constantly 

 visiting the flowers for this purpose. One of them remained for 

 a long time, and the loads of purple pollen in the pollen-baskets 

 were plainly visible. Two females of Halictus craterus came for 

 pollen. A bumblebee inspected the flowers, but did not alight. 

 A small undetermined bee flew from flower to flower apparently 

 looking for pollen. At 1:35 p. m., there were no insects on the 

 flowers; but a little later a small species of Halictus, and also a 

 female of the larger Halictus craterus arrived and removed all 

 the pollen remaining available. On three other occasions a 

 female Halictus craterus was seen collecting pollen, which in one 

 instance colored purple the under side of the abdomen and the 

 brushes on the posterior legs. No attempt was made to capture 

 any of the bees since this would have lessened the normal number 

 of visits. 



The nectarless flowers of Clematis were not, therefore, entirely 

 neglected by insects; but were visited by a number of bees suffi- 

 ciently large to remove all the pollen they produced, and to have 

 effectively pollinated the stigmas had they been in a normally 

 receptive condition, and as this is all that is required, additional 

 visits would have been of no advantage. The sterility of the 

 flowers is not thus due to the absence of pollen-carriers as Plateau 

 supposed. The flowers should be examined immediately after 

 anthesis before the pollen has been removed; since Plateau 

 makes no mention of the pollen he probably did not observe 

 whether it was removed or not. = » I inspected the flowers many 

 times without finding any insects, and it is easy to understand 

 how a casual observer might gain the impression that they were 

 entirely neglected. Plateau's failure to discover insects on the 

 flowers in their natural condition may have been partly due to an 

 insufficient number of observations, partly to location, and partly 

 to the absence of suitable species of bees. Bumblebees are not 

 well adapted for gathering the scanty supply of pollen, and prob- 



« Cowles has suggested that Plateau failed to see the earlier visits of his insects, 

 Cowles, H. C, " Insects and Flower Colors," Bot. Gaz., 39:70, 1905. 



