Vol. XXV] ENTOMOLOGICAL NEWS. 71 



with a short flight. In these cases there is no evidence that 

 the oligotropy is the result of the short flight. On the other 

 hand there are enough certain cases to establish the presump- 

 tion that the short flight is a result of the oligotropy. 



Oligotropic bees are no smaller than their polytropic rela- 

 tives, and the percentage of small bees is no greater than 

 among the polytropes. In my neighborhood 38% of the oligo- 

 tropes and 37% of the polytropes are large. 



The long-tongued oligotropes and their relatives are among 

 the swiftest of bees, far surpassing Bomb us in this respect. 

 Lovell seems to regard small size as an indication of a weak 

 flight. At any rate, he speaks of Andrena illinoensis as "a 

 small bee, not likely to fly far," and of Ha-lictoides novae- 

 angliae: "They are small bees with a weak flight." This re- 

 quires proof. When the proportions are the same there is a 

 probability that a small bee has a stronger flight than a large 

 one. 



I have shown that Emphor boinbiformis nests in the neigh- 

 borhood of the Hibiscus on which it depends. The proximity 

 of the nests and food plants is a result rather than a determin- 

 ing condition of the oligotropy. 



At Carlinville the maximum of Compositae is in August and 

 September. Of the nectar flowers observed by me in these 

 two months seventy-two, 32%, are Compositae. There are 

 fifteen species of inquiline bees flying late and forming a maxi- 

 mum under that of the Compositae. They make from three to 

 thirty visits and an average of fifteen. On the average they 

 make visits of 6% to a flora composed of 32% of Compositae. 

 They seem to fill the conditions required by Lovell 's theory: 

 a short flight of 60 days average determined by the fact 

 that they are inquilines of bees most of which are evidently 

 oligotropes of Compositae. a rather weak flight, and probably 

 come from nests conveniently located with reference to the 

 Compositae. They might easily confine 30 visits, or an aver- 

 age of 15, to the 72 Compositae. Only three species, with an 

 average of 5 visits, confine themselves to the Compositae, 

 while twelve species, with an average of 17 visits, do not. The 

 exclusive ones are Elpeolus autumnalis 7, Holonomada vincta 



