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 hi 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 (Volucella esuriens Fab. var. 



