POLLINATION OF THE MANGO. 5 
• 
tumid disk secretes a thick, sweetish fluid which stands out upon 
its surface in small globules, collecting in larger quantities at the 
bases of the petals. Insects are attracted to this nectar by the 
fragrance of the flowers, presumably, and their visits are numerous, 
especially during the early hours of the day, from daylight until 9 or 10 
o'clock a. m. Many insects were observed feeding upon this nectar, 
and after their visits it was found that there was practically none of it 
left upon the disk. In moving over the flower in order to get at all 
sides of the disk, it is almost impossible for an insect of any consider- 
able size to avoid brushing against the anther and dislodging some of 
the pollen, and in this way transferring the pollen to the stigma, since it 
is sufficiently rough to cling to the body of the insect and its transport 
can be effected. It is evident, however, from the comparatively 
small number of stigmas pollinated that large quantities of pollen are 
not carried on the bodies of insects, and this belief was confirmed by 
observation. Examination of insects taken from the flowers has never 
revealed more than seven or eight pollen grains clinging to their 
bodies, and not more than one to three or four grains were usually 
found. The pollen itself is not very abundant, and the number of 
grains which become attached to the body of each insect visitor is 
certainly not large. 
Of the principal insects observed upon the flowers of the mango in 
the vicinity of Miami it is necessary to treat in some detail. Those 
which were captured during the months of March, April, and May, 
1915, when most of the mangos were in bloom, and have been 
identified by the Bureau of Entomology, through the courtesy of 
Dr. L. O. Howard, Chief, represent the four orders Diptera, Hymen- 
optera, Lepidoptera, and Coleoptera, ranking about in the order 
given as to the importance and frequency of their visits. The flies 
are the only insects which are nearly always present upon mango 
flowers at any time of day. As they are not so active as some of the 
Hymenoptera and remain upon a single flower for a longer time, 
they are scarcely so conspicuous in the early morning as some of the 
latter, which on sunny mornings can be seen buzzing about the trees 
in considerable numbers. The commonest fly which was taken on 
mango flowers was Ravinia sp., an insect slightly larger than the 
common house fly, with a grayish body. Somewhat less common 
were two species of Sarcophaga, with bodies about 1 centimeter in 
length, the thorax longitudinally striped with black but the general 
color grayish. A bluebottle fly (Lucilia caesar L.) and another 
bluish green species slightly larger than a house fly, the screw-worm 
fly (Cochliomyia macellaria Fab.), were not common, but a few 
specimens were taken. Still less common were two very large flies, 
one a horsefly (Tabanus americanus Forst.) which was seen upon the 
flowers occasionally, and another (VoluceUa esuriens Fab. var. 
