335 



Darwin's pxperimcnts in tliis diroction an' especially valuable. He protected 100 

 heads of Red Clover {Trifolium praienHc) with n<'ttin^ in such away as to prevent 

 the visits of insects and found that not a singhi seed was produced, although 100 

 heads visited by bees at the same time produced 2,720 seeds. Striking results were 

 also obtained with other clovers. Five or six times as many seeds of Scarlet Italian 

 Clover ( Trifolium incarnatum) were produced when bees were allowed to visit the 

 blossoms as were obtained from the same number of blossoms covered with netting. 

 Cross-fertilized plants of common White Clover {Trifolium r<'2)e)iH) yielded, in Dar- 

 win's experiments, ten times as many seeds as plants fertilized with their own pollen. 

 In another experiment 20 unprotected heads of White Clover gave 2,290 seeds, while 

 20 heads from which insects were excluded gave but a single seed and that im- 

 perfect. 



As Bumble-bees visit Howers of Red Clover more than do other bees, and the size 

 and weight of their bodies is such as to render them capable of eftectiug the fertili- 

 zation of the flowers, it is safe to saj^ that they ai"e the chief agents. In attempting 

 to secure the honey located in the nectary at the base of the stamens, the Bumble- 

 bee presses the keel or carina and the ahe (wings) of the flower downward, and the 

 style being curved, with the terminal stigma rising above the surrounding anthers, 

 the stigma strikes the underside of the bee's head and receives the pollen brought 

 from another clover blossom, and the stamens, which are shorter than the pistil, only 

 touch the bee after fertilization has been accomplished and yield their pollen for the 

 next fertilization. 



The common Bumble-bee was imported by the British Government into Australia 

 and New Zealand about the year 1884 for the express purpose of eftectiug the fertili- 

 zation of Red Clover in those colonies. After various trials the experiment was suc- 

 cessful. The hibernating queens, for which one shilling (24 cents) each was paid, 

 were packed in moss, placed in the refrigerator of the steamer, and were gradually 

 revived upon approaching their destination and then set free. Official reports con- 

 cerning the results of the experiment are not at hand, but numerous reports in the 

 press have shown that the experiment was successful; that the bees have multiplied 

 with wonderful rapidity and spread over the whole of the cultivated portion of the 

 country in these comparatively few years, and that abundance of seed is produced as 

 a result, where before Australia and New Zealand had to import their Red Clover 

 seed. 



Chapter xvi in volume I of Cheshire's " Bees and Cee-keeping," entitled " Bees as 

 Fertilizers," would doubtless give you information which you could use in handling 

 this question.— [March 12, 1892.] 



GENERAL NOTES. 



INSECTS ON THE SURFACE OF SNOW. 



We have seen during the winter a number of newspaper items stat- 

 ing that in diiferent parts of the country insects of one sort or another 

 had been observed in great numbers upon the surface of snow. In no 

 case in the newspaper accounts were the particular species determined 

 scientifically. 



On February 11 Mr, John Burroughs, of West Park, N. Y., sent us a 

 number of half-grown larvae of Leucania phragmatidicola, which were 

 found on snow in the fields and along the roads, usually not far from 

 trees. This was immediately after a snowstorm. A week later, on 



