﻿380 Lovell : The Insect- Visitors of Flowers 



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Corxus Canadensis L. Bunch-berry. 



Flowers small and closely capitate with a single central floret 

 and four lateral clusters, consisting, respectively, in one instance, 

 of i, 10, 9, 14 and 12, — or 46 florets in all. Conspicuousness is 

 gained by four parallel -veined involucral bracts. Parts of the flowers 

 in fours, petals valvate, and one, or not rarely two, awned. As the 

 flower-bud approaches maturity the filaments grow rapidly, breaking 

 apart the petals at the base and protruding as four V-shaped arches. 

 If at this stage the awl-shaped appendage is touched by the body of 

 an insect, or by a needle, the petals are instantly reflexed, the elastic 

 filaments straighten, and a minute shower of pollen is projected 

 upward. In fully matured flowers a faint snap may be heard. 

 Self-fertilization is prevented by the immaturity of the stigma. 

 The stamens surpass the pistil and in the bud the anthers rest 

 against the style. Both stamens and petals soon fall away and 

 the capitate stigma, composed of white papillae, subsequently ma- 

 tures. Though self-fertilization is prevented by proterandry there 

 may occasionally be observed resting against the stigma the an- 

 thers of neighboring flowers. The honey is secreted in a very 

 thin layer by a dark brown ring at the base of the style. There is 

 a profusion of flowers, which remain in bloom a long time. 



While the honey-bee and Andrenidae are common visitors 

 there has never been seen upon the flowers a single species of 

 Bombus. The absence of these insects is probably due to the 

 small store of honey. Several small butterflies are occasionally 

 attracted, but coleoptera are very rarely taken. A large company 

 of diptera are important agents in inter-crossing. The flowers are 

 frequented by a white spider, Misumena vatia, which preys upon 

 the insects guests ; in one instance it had captured a honey-bee, in 

 another a crane-fly. 



Visitors: A. Hymenoptera— (a) Apidae : (1) Apis mcllifi 

 L., $ , common ; (2) Nomada maculata Cr. ; (b) Andrenidae: (3) 

 Andre na vicina Sm., 9, common; (4) A. cammoda Sm., ? ! (5) 



A. claytomae Rob., 9, common; (6) A. designate Ashm., 9 I W 

 Hal ictus stultus Cr., $■ (8) H. Cressonii Rob., 9; (9) #***** 

 sp. ; if) Ichneumonidae : (10) Ichneumon centrator Say, S, ™ xc ; 



B. Lepidoptera *" "" ' ' 



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pscudargwius t>w» & 

 n ■ (j ^ Thecla niphon 



