40 NATl'RE SKETCHES IN TEMPERATE AMERICA 



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^'(Bkr!^^^^ The Selpxteu Guests of 



■.a^ ' Jf'*2<l2jQJ THE BlITEEFLY WeED 



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"OW Inilliant ilie flowers of the orange 



Ijutlerfly weed ai)i)ear in tlie field, when 



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I I viewed in the bright sun ol a July da\! Under 



these conditions they show with a splendor only 

 known to the flowers of this species. Not only tlie rich color 

 of the blossoms appear to have charms for insect guests, Init 

 the ]iollen and sweets seem to meet their most exacting whims. 

 A veritable entomological garden is spread before us as we 

 approach. \'arioiis winged insects, from butterflies to small 

 flies, are all busily occupied among the blos.soms. Nearby 

 are half-opened flowers of the goldenrod and the preLly, 

 scented, lace-like flowers of the wild carrot, but they are for 

 the moment completely ignored by these special insect guests. 

 I have already considered the structure of the blossoms of 

 the common milkweed and have endeavored to show how the 

 delicate and weaker flies and bees sometimes fall victims by 

 having their feet entangled in the pollen masses of the flowers. 

 These pollen organs or corpuscula become clasped, as if animated, 

 to the feet of certain insects. Some of the weaker insects are 

 unable to disentangle themselves, and these ciijjtives either 

 die of exhaustion or fall prey to tlie ;iiiLs, which often swarm 

 upon these plants. The larger insects,= such as the wasps, 



