34 Bulletin Wisconsin Natural History Society. | .Vol. 7. Nos. 1-2. 



duced within the last decade is mostly unfavorable to Hermann 

 Mueller's theory, according to which certain types of insects show 

 a preference for certain colors. Lovell 18 , who has treated the 

 color question in its various aspects in a most thorough manner, 

 readies the conclusion, that long-tongued bees (which were be- 

 lieved to favor blue), and butterflies (considered having a prefer- 

 ence for red) "are influenced more by the form of the flower than 

 by its color." Prof. T. D. A. Cockerell 19 , has given us some very 

 interesting information on the relation of the bees of the genus 

 Perdita to flowers, mainly Composite, and he considers the di- 

 mensions of the tube (length and width) of the greatest import- 

 ance in this respect. 



I shall proceed to compare flowers agreeing in tube length, 

 but differing in color, and shall at first consider the native species, 

 reserving the introduced species for a later discussion. 



Tube length 1 mm. 

 There are 3 species* with white flowers (Bupatorium pcrfolia- 

 tum. Aster laterifloriis and Brigeron animus, the latter two with 

 white rays, and a yellow disk), and 2 with yellow flowers (Soli- 

 dago canadensis, and S. juncca.) The average percentage of allo- 

 tropous. hemitropous, and eutropous visitors for the yellow, as 

 also for the white flowers is as follows 



Allotr. Hemitr. Eutr. 



Yellow 56.9 36.1 7.0 



White 52.9 41.7 5.4 



These figures come pretty close together, the difference is cer- 

 tainly too small to be of any importance. It will be noted how in 

 both groups the allotropous visitors predominate, a fact empha- 

 sized above under tube length. 



Tube length iy 2 mm. 



Here we have a yellow (Solidago graminifolia) , a white (Aster 

 furcatus) with white rays, and a yellow disk), and a blue (Aster 

 macrophyllus with blue rays, and a yellow disk) flower. 



Allotr. Hemitr. Eutr. 



Yellow 38.5 50.4 11.1 



White 25.6 58.1 16.3 



Blue 33.7 49.5 16.8 



18) John H. Lovell, loc. cit., pp. 456-479. 



19) T. D. A. Cockerell. The bees of the genus Perdita F. Smith. Proc. 

 Acad. Nat. Sc. Phil., 1896, p. 41. 



*) All of them blooming synchronously, and therefore exposed to the 

 samp insect-fauna. For details see the lists of visitors following an account 

 of the species in the second part of this paper. 



