98 Bulletin Wisconsin Natural History Society. [Vol. S, No. 2. 



7 years, and show that B. discolor is a very regular visitor of Pul- 

 iiwnaria offcinalis (Boraginacar) , and that it prefers the flowers 

 of this to those of any other species, visiting other flowers in the 

 case of necessity only. In Pulmonaria offcinalis a change of color 

 takes place from red in the younger to blue in the older flower, 

 and Bombxlius discolor is seen to favor the red flowers and spend 

 more time at them for the simple reason, as Langhoffer states, 

 that they contain more nectar than the blue ones. In the case of 

 Bombxlius fuliginosus this author noticed a preference for the 

 blue tubular flowers of Muscari neglectum ( Liliaccw ). 



In our region Bomby lifts major, the earliest of our Bombylids 

 flies from about the 26th of April to the end of July. During the 

 first few weeks of its period of flight it may be seen at the white 

 flowers of Antennaria neglccta, Primus nigra and Sangiiinaria 

 canadensis ( the latter a so-called pollen-flower, one in which no 

 nectar is secreted), the yellow flowers of Colt ha palustris, Ranun- 

 culus scptcntrionalis and Sali.v rostrata ( probably also on some 

 other species of Salix), the red flowers of Claytonia virginica, and 

 the violet flowers of Vicia caroliuiaua, Cardaminc Douglassii and 

 Hepatica acutiloba, the latter also a pollen-flower. 4 ) It is a rather 

 frequent visitor at the red flowers of Claytonia virginica, without 

 however showing a decided preference for this species. 



Structure of the flower, odor, taste and supply of nectar de- 

 termine probably more than anything else the extent to which a 

 flower is attractive to such an insect. As stated above Langhof- 

 fer explains the more frequent and longer visits of Bombylius 

 discolor to the younger red flowers of Pulmonaria as being due to 

 the greater amount of nectar contained in these than in the older 

 blue flowers. If we could change the color of such a flower to 

 white or yellow without changing its structure and the odor and 

 taste of its nectar there is hardly any reason to doubt, that it 

 would prove as attractive to Bombylius discolor as otherwise. The 

 same may be said for the blue flower of Muscari neglectum in its 

 relation to Bombylius fuliginosus. 



II. FLOWERS VISITED BY SHORT-TONGUED BOMBYLIDS. 



For the short-tongued species belonging to the genera Loma- 

 tia, Anthrax and Argyramceba (Spogostylum) it has been 



4) Regarding pollenflowers and Bombylids we have the following in 

 Knuth's Handbook. Vol. 1, p. 1S3 : "The species of Bombylius like those of 

 Empis are also able to bore into succulent tissues." Further on, following a 

 discussion of the anatomy of the mouthparts we read: "I have often seen 

 species of Bombylius thrust their proboscis into nectarless flowers (e. g. Bom- 

 bylius canesaens Mik into Hypericum perforatum), and I imagine that here the 

 boring apparatus was brought into action." 



