40 PROCEEDINGS OF THE ACADEMY OF [1896. 



stance, in fact, of the neotropical immigrants adapting themselves 

 through modification to subboreal conditions. 



Another thing that deserves notice is the relationship between the 

 size of the bees, the length of their tongues, and the kinds of flowers. 

 It would appear that a longer tongue is not always developed inde- 

 pendently to meet requirements, but that the total size of the bee 

 may be increased, and with it the tongue. Or conversely, the size 

 of the bee may be reduced. Speculations of this kind are, perhaps, 

 not very profitable, but it will be advantageous to give the facts 

 which suggest them. 



Close to the N. M. Agricultural College Verhesina encelioides und 

 Bigelovia ivrigJitii grow in the utmost profusion. In September col- 

 lections were made off both, the plants being but a few yards from 

 one another, with the following results: — 



Verbesina : — Perdita, Calliopsis, Pamir'gus, Melissodes, CcelioxySy 

 Andrena, Epeolus ; but on October 5th when the Bigelovia was getting 

 over, Halidus ligatus, H. pedoraloides and Agapostemon inelliven- 

 tris. 



Bigelovia: — Perdita, Agapostemon, Anthophora (small species), 

 Megachile (one), Colletes, Halidus $ , Halictus stultus 9 , Prosopis^ 

 Nomia nevadensis. 



Thus it will be seen that the bees of these two plants were almost 

 entirely of different genera in September, those on the Verbesina 

 being Apidte with few exceptions, those on the Bigelovia largely 

 AndrenidjB. But as the Bigelovia began to be over, the large 

 Andrenidre visited the Verbesina, which had given a second crop 

 of flowers. Now although Perdita appears equally in both lists, the 

 species are different, and if we except unique specimens, as we justly 

 may, those on the Verbesina are of larger size, those on the Bigelo- 

 via comparatively small. The abundant larger verbesince is never 

 seen on Bigelovia, nor the not less abundant smaller luteola on Ver- 

 besina. 



And when we come to look at the Perdita spp. of the Gutierreziay 

 they average still smaller than those of the Bigelovia. 



I am fortunate in being able to present some figures of the flow- 

 ers of some of the Perdita Compositfe, drawn by Miss Mae Gilmore 

 under the supervision of Professor E. O. Wooton. As they are all on 

 the same scale, (diam. x 5) the reader will be able to form his own 

 conclusions by studying them in connection with the facts above cited. 

 " The honey ... in Compositse is secreted by a ring surrounding 



