120 BOTANICAL GAZETTE. [ May* 



have been found, and Mr. W. P. Blake found diatoms in the 

 hot waters of the so-called " geysers" of California and Ne- 

 vada hot springs. 



U. S. Geological Survey, Washington , D. C. 



Flowers and Insects, I. 



CHARLES ROBERTSON. 1 



Delfh 



The flower agrees in most 



respects with D. elatum, as described by Miiller. 2 



It is blue, 8ut the exposed parts of the two upper petal 

 which arch over the entrance to the spur are white, forming 

 a sure guide to the nectar. In D. Ajacis, according to 

 Sprengel (702), 3 the upper petals also form the pathfinders 

 by a variation in color. In D. elatum yellow hairs on the 

 lateral petals form the guides*, while in D. Consolida path- 

 tinders are wanting (Miiller). 



The lower petal has disappeared, since its attractive func- 

 tion has been usurped by the sepals. It is unnecessary as a 

 protection to the stamens and pistils, and. its presence in the 

 median line would only prevent proper contact with the an- 

 thers and stigmas. 



I he parts whose function has been most imperfectly ex- 

 plained are the two lateral petals. These close over the 

 numerous stamens, completely hiding them, but an entrance 

 to the spur is left between them and the upper petals. When 

 a bee visits the flower, the lateral petals are forced aside, and 

 the under side of the bee's head comes in contact with the 



1 The following 



1886, near Carlinvi. 



lecting and determining 



present to give only a list of visitors. 



pi^ociii, iu give vui\ a nsi or visitors. 



Mr. Cresson has com red my bees with his own tvpe specimens in the collection of 

 a i ?v ■ S?i7. can Etiological Society, except species of Halictus and Andrena. Professor 

 B.W. VVilliston has kindly identified the Diptera. Mr. C A. Hart and Mr. Samuel Hen- 

 snaw have aided me in identifying the Coleoptera. Prof. G H. French and Mr. Hart have 

 named a number of Lepidoptera for me. I am also under obligations to Prof. S. A. Forbes 



s to the collections and literature of the Illinois State Laboratory of Natural His- 



for access 



- v . *««. W w«jwiwuon8 ana literature ot tne Illinois State Laboratory of Natural til 



torv and to Prof. \\ llUam Trelease for access to his valuable index of the bibliography 



and to much of the special literature of fertilization. Prof. Trelease has also placed at my 



disposal his unpublished notes on the subject and a collection of insects which he has 

 taken on flnwprs 



* S^ 88 otherwise specified, all references to Miiller are to Herman Miiller : Fertiliza- 



RroYv wSK e £i' Seeal8 °on this specie Delpino: Ulterior! 0s« rvazioni, and Lubbock : 

 British Wild Flowers. 



^f thJm nun iher V 1 . 1 E5^? nt ^ € after pr.aut n.imer. r to Thompson's bibliogra] f 



01 trie literature of fertilization, which Is printed with Midler's Fertiii tion of I '• 



as una book U the most important source of information on the liierature, reference are 

 practically thrown away on all who do not have ac< to it. 



