292 ANNALS NEW YORK ACADEMY OF SCIENCES 



Dr. Britton visited all the xerophj'tic portions of the island in order to 

 study Cactuses in nature. He succeeded in making observations on all 

 the recorded species except one. Grisebach has defined Jamaica as a 

 floral region by itself. The flora is more nearly like that of Central and 

 South America, than of any other of the Antilles. 



Professor Wilson reported that he had spent the summer collecting 

 insects over a great part of the United States to procure material for his 

 studies on chromosomes. He was very successful, procuring a large series 

 of species, and many insects of each species, especially Hemiptera, Neu- 

 roptera and Coleoptera. 



He found especially interesting his trip across the southern belt from 

 the Atlantic to the Pacific. Specimens of the insects collected were ex- 

 hibited in connection with Prof. Wilson's talk. 



Professor Wheeler gave an account of his ex|Dedition to Florissant, 

 Colorado, with Professor T. D. A. Cockerell of the Universitv of Colorado, 

 for fossil insects, which are found more abundantly here than anywhere 

 else in the world. Florissant is situated near West Park, Colorado, and the 

 insects are found in the bed of a Tertiary Lake Basin, which in ancient 

 times probably drained into the Arkansas. There is now very little water 

 left in it. The altitude is 8150 feet and the climate is now sub-boreal. 

 Consequently the flora resembles that of Greenland and Siberia. The 

 remains of insects found in the shale, however, show that in Tertiary times 

 the climate was more like that of Georgia or Alabama. 



The ancient lake was probably covered from time to time by volcanic 

 ashes which imbedded any insects or plant remains that fell into the lake. 

 The fossil-bearing strata are very thick and exposed only at certain points. 

 Leaves of such trees as sequoia, cottonwood, etc., are abundant, while 

 ants are the most abundant of the insects. 



Professor Wheeler remained at Florissant about a month and obtained 

 about 2000 specimens, mostly ants and plants, many of which are in a fine 

 state of preservation. The investigation of the forms thus far shows that 

 these Tertiary insects were very similar to those now living there, showing 

 the remarkable stability of insect types from Miocene times. 



Mr. Beebe reported an interesting series of experiments on the effect of 

 subjecting different species of birds to intense humidity. For example, 

 Inca Doves were kept in an intensely humid atmosphere through two molts, 

 with the result that the birds' plumage changed in such a way as to cause 

 them apparently to pass through two subspecies. The plumage in general 

 was darkened while the wing-feathers were whitened. Experiments on 

 the White-throated Sparrow produced no change after the first molt, but 

 after the second molt there was a remarkable change to a dark mahogany 



