April, '11] WASHBURN: CLOVER FERTILIZATION 141 



two years ago by Mr. Ruggles, later joined by Doctor Franklin. We 

 have recently added to our force, under the provisions of the Adams 

 Act, Mr. Theodore Urbahns, who is, at present, giving his entire time 

 to this problem. Mr. Urbahns has invented a cage which seems to 

 answer the purpose for which it was intended excellently well. This 

 cage is made of a wooden frame, covered with white cheese cloth on 

 three sides and on the top. A loose glass plate forms the fourth side. 

 The floor is of wood, perforated in the center in such a way as to allow 

 clover heads from two or more plants to be introduced into the cage. 

 The cage is suspended over the growing plants. The perforations 

 through which the clover heads are introduced can be shut to exclude 

 other insects, and to keep the clover stems in place, by means of two- 

 wooden shutters. 



The method of procedure in securing the cross pollination of the 

 florets has been to confine the green heads in other cages, made of 

 mica lamp chimneys closed at the top with a piece of cheese cloth, and 

 at the bottom with a fold of the same kind of cloth, which can be 

 firmly tied around the stem bearing the introduced head. This cage 

 is held in place above a plant by a cord from above and below. This 

 latter apparatus was suggested in an article by C. E. Hood in the 

 April, 1909, number of the Journal of Economic Entomology. 

 Of course, these heads might have been covered with cheese-cloth 

 bags, but in that case could not have been so easily watched. When 

 the florets open and are ready for pollination, they are removed from 

 the mica cages and introduced into the cage made by Mr. Urbahns, 

 and described above. Into this cage, one or two bumblebees are 

 introduced, and we found that early in the season the bees worked 

 faithfully every day, after becoming accustomed to their prison, 

 occasionally as long as three weeks. Later in the season their work 

 was not quite so satisfactory, but when captured early in the morn- 

 ing they usually worked well for a few hours, after which time they 

 were liberated. When these clover blossoms have been thoroughly 

 gone over by the bees, they are removed from the pollenizing cage, 

 and again placed in the mica cages for future use in Briichophagus 

 studies. 



At the close of this paper Dr. A. F. Woods, dean of the College of 

 Agriculture of the University of Minnesota was introduced by the 

 President. 



Dean Woods: I do not like to break into this program, but I 

 wanted to come up and see some of the familiar faces, and welcome 

 you to this branch of the university. I think we have a very high 



