ADAPTATIONS IN ANIMALS AND PLANTS 41 



make their escape, carrying away the polhnia, which they trans- 

 port to other blossoms during their visits. In this way they 

 bring the pollen in contact with the stigma, and thus fertihze 

 the flowers. But the butterfly weed differs from the common 

 milkweed in possessing the allurements of "brilliant color, though 

 without fragrance. The weaker insects that frequent these 

 blossoms are not destroyed in such numbers. 



To the butterflies, the floral spread presents an enticing 

 playground, as well as a place to banquet. And even the 

 weak flies and small bugs move about among the bright flowers 

 with impunity. But upon one wasp, Ammophila, and sev- 

 eral bees, Bombus, the butterfly weed unconsciously enforces 

 the more serious burden of hterally compelUng the trans- 

 fer of pollen. When I carried this inquiry a httle further, 

 one day, by sweeping the insects one by one into my net, I 

 found in the general round-up the following representatives: 

 one large, slender- waisted wasp, Ammophila; three Argynnid 

 butterflies, Argynnis cyhele; one of the cr€;scent-spot butterflies, 

 Phyciodes tharos; one Ajax butterfly, a number of bees of the 

 genus Bombus; several small, clear-wing flies, and two small 

 bugs. 



On examination of their feet with a hand magnifier, the real 

 pollen carriers were revealed at once. The wasp's feet had a 

 number of the pollinia attached to the hairs at different parts 

 of the tarsi, while the bees' feet were fairly loaded with them. 

 But as to the rest of the insects enumerated, I found their 

 feet entirely free from polliniae, they haviijg escaped the pollinia 

 traps set only for the larger forms that I have mentioned. 



When finding the butterfly weed on some bright day, let 

 the reader stop and meditate, and study the insect visitors, 

 before thinking of recklessly picking these exquisite flowers 

 that adorn the outdoor landscape. Then let me hear from 

 those who have made new additions to the list of these flower 

 frequenters, which I have only suggested in my sketch. 



