146 
IOWA ACADEMY OP SCIENCES. 
POLLINATION OF CUCURBITS. 
BY L. H. PAMMEL AND ALICE M. BEACH. 
During the season of 1892 one of us was engaged in crossing 
some of the cultivated cucurbits. Incidentally some attention 
was given to their pollination. As comparatively little has been 
published concerning the pollination of these plants, these notes 
may be of interest. 
The insects collected in 1892 were identified by Mr. Gossard, 
who assisted in noting them in the field. We are greatly indebted 
to Mr. Charles Robertson for determining some of the Hymen- 
02 )tera. Mr. Stewart, who assisted in crossing cucurbits, also 
frequently noticed the honey bee on various cultivated forms of 
the CucurbitacesB. Most of the drawings were made by Miss 
Charlotte M. King. 
The literature on the pollination of Cucurbitaceee is very 
scanty. The European Bryonia dioica was studied by Herman 
Muller. ^ Mr. T. C. Gentry^ has given a short account of Gucur- 
Jjita ovifera and C. pepo, but it is quite inaccurate in some impor- 
tant particulars. G. O. MtilleU has also given a short account. 
The species considered in this paper are pollinated mainly by 
insects belonging to the order Hymenoptera. The assumption 
of Thomas C. Gentry that they are pollinated by the agency of 
the wind is erroneous. G. O. Mtiller^ is correct when he states 
that wind pollination is excluded because of the large size and 
the small number of pollen grains. 
SEX IN CUCURBITACE^. 
They are usually said to be monoecious or dioecious, although 
G. O. Muller says occasionally polygamous. It has been known 
for some time that the same species are polygamous and dioe- 
cious. 
(1) Fertilization of Flowers, English Translation, p. 368. 
(2) American Naturalist, Vol. IX, p. 363. 
(3) Die Naturelichen Pflanzenfarailien Engler and Prantl iV. Theil 5 Abth. Bogen 
3, p. 8. 
(4) L. C-, p. 264. 
