ALFALFA SEED PRODUCTION. if 
_Honeybees are not nearly so effective as bumblebees, but should not 
be underrated in this connection, while bees of the genera Andrena 
and Megachile and various butterflies are also valuable agents in 
pollinating alfalfa flowers. 
Results are also given showing the seed production of plants whose 
flowers were artificially tripped in comparison with untreated plants. 
At Arlington. farm, Virginia, artificial tripping resulted in an increased 
production of 25.5 per cent, while at Chico, Cal., an increase of 129 
per cent of pods was obtained. 
Piper,! in a report of the American Breeders’ Association committee | 
on forage crops relating to the breeding of alfalfa, gives an epitome of 
the answers of members to various subjects of inquiry, five of which 
relate to pollination. The answers are diverse, some of them based 
on experiment and careful observations and others more or less. 
expressions of opinion. 
Westgate ? records that he observed over 500 visits of honeybees 
to alfalfa flowers, the flower being tripped in but one case. 
Wildermuth * records with some doubt that he has seen the butter- 
fly of the alfalfa caterpillar (Hurymus eurytheme) trip alfalfa flowers. 
In a personal interview he states that he observed five or six indi- 
viduals trip the flowers during one season, but has not seen it since, 
though he has frequently watched the butterflies. This butterfly is 
very common on alfalfa throughout the Western States. 
It will be noted from the brief reviews given that investigators have 
differed as to their conclusions on several points in connection with 
the pollination of the alfalfa flower. The most important questions 
that affect the problem of seed yield left in doubt are the following: 
1. To what extent are the flowers self-fertile? 
2. Is cross-pollination more effective than self-pollination? 
3. Do alfalfa flowers trip automatically? 
4. Do untripped flowers form pods and seeds? 
5. Is the rupturing of the stigma essential to its becoming receptive? 
6. To what extent do honeybees trip alfalfa flowers? 
In the investigations reported in this paper will be found abundant 
data which go far to clear up the discrepancies in previous work. 
STRUCTURE OF THE ALFALFA FLOWER. 
The structure of the alfalfa flower has been described and illustrated 
in detail by Hermann Miller and other writers. The most interesting 
feature is the explosive apparatus which functions to facilitate poll- 
nation and under proper conditions to favor cross-pollination.. The 
1Piper,C. V. Alfalfa and its improvement by breeding. American Breeders’ Association, Report, v. 5, 
1908/09, p. 94-115 1909. 
2Westgate, J. M. Methods of breeding alfalfa by selection. American Breeders’ Association, Report, 
v. 5, 1908/09, p. 147, 1909. 
8Wildermuth,V.L. The alfalfa caterpillar. U.S. Department of Agriculture, Bureau of Entomology, 
Circular 133, p. 1, 1911. 
