fi6 

 by Apis mellifica and the Diptera by several species of 

 Syrphus flies. 



Lagenaria vulgaris Ser. The muskscented flowers of 

 the dipper gourd have a funnel or bell-shaped calyx with a 

 long tube. The white petals are persistent a much longer 

 time than in Cucurbita pepo and the nectar is not so easily 

 accessible and exposed as in Citrullus and Cuciirbiia. 

 The three stamens eftectually block the way for the larger 

 insects. The flower is adapted to humming birds, which can 

 easily get to the nectar with their long tongues. The color 

 and odor would seem to indicate that it is adapted to Sphingi- 

 dae, but as the plants were so far away observations were not 

 made at night. In addition to the humming bird,, ^om^MS 

 pennsylvanicus was observed collecting pollen. Diabro- 

 tica vittata was abo observed covered with pollen. 



., ^ ...^ Members of the carrot family are not highly 



Umbel tlferae. ^ & j 



specialized; nectar occurs in open flowers 

 and is accessible to short tongued insects. The individual 

 flower is not conspicuous, and so far as our own species are 

 concerned, are without the attractive flowers, but since the 

 flowers are massed they are rendered attractive. Zizia and 

 Pimpinella are proterogynous while I/eracleum and, Sium 

 are proterandrous. Mr. Robertson speaking of insect visit- 

 ors says: "The character of the visitors of JJmbelliferaei 

 therefore, must depend upon the insects to which they are 

 exposed, i. e. upon the time of blooming. Indeed, the time 

 of blooming is almost or quite as important as modifications 

 to hide the nectar. If we take three white-flowered . forms 

 with exposed nectar, but appearing at difterent times, we 

 will find the extremes in characters of visitors. Thus, B/n- 

 genia shows the highest proportion of bees Eulophus the 

 highest proportion of fties, Gicuta the highest proportion of 



