FLOWERS AND THEIR WORK 



43 



A humming bird just about to cross-pollinate 

 a flower. 



parts of the bee are complex. The parts consist of a pair of very small 

 jaws or mandibles, certain other .structures, maxillm, part of the lower lip 

 called the labial palps, and 

 a long tonguelike structure 

 called the ligida. The uses 

 of the mouth parts may be 

 made out by watching a bee 

 on a well-opened flower. 



Other Flower Visitors.' — 



Other insects besides the 

 bee are pollen carriers for 

 flowers. Among the most 

 useful are moths and but- 

 terflies. Both insects feed 

 only on nectar, which they 

 suclv through a long tube- 

 like proboscis. The heads and bodies of these insects are more or 

 less thickl.v covered with hairs, and the wings are thatched with 

 hairlike, tiny scales. All these structures are of use to the flower 



because they collect and 

 carry pollen. Projecting 

 from each side of the head 

 of a butterfly is a fluffy 

 structure, the palp. This 

 collects and carries a large 

 amount of pollen, which is 

 deposited upon the stig- 

 mas of other flowers when 

 the butterfly pushes its 

 head down into the flower 

 tube after nectar. 

 Flies and some other insects are agents in cross-pollination. 

 Humming birds are also active agents in some flowers. Snails 

 are said in rare instances to carry pollen. Man and the domesti- 

 cated animals undoubtedly frequently pollinate flowers by brush- 

 ing past them through the fields. 



' If the study of other inserts is taken up in the fall in connection with the flower, 

 the student should be referred to parta of Chapters XX and XXI and to the Lab- 

 oratory Manual. 



The common swallow-tailed butterfly on clover. 

 Bumblebees usually are the agents which 

 cross-polUnate this flower. 



