14 FOOD OF THE FLYCATCHEKS. 



8 were workers, and 2 indeterminate. When we consider that in the 

 stomachs examined there must have been at least 10,000 insects, and 

 probably three times that number would be nearer the mark, it will 

 at once be seen that the proportion of honeybees in the kingbird's 

 diet is small. 



Other Hymenoptera in the kingbird's food are ordinary bumble- 

 bees, wasps, and hornets of various species, of which probably the 

 best that can be said is that they perform a useful function in the 

 fertilization of flowers. As there is little danger that there will ever 

 be too few of them for this service, the birds are doing no great harm 

 in feeding upon the surplus. 



Hemiptera (bugs) are not an important element of the kingbird's 

 food, though they were found in the stomachs of every month except 

 March. In April the} r amount to 7.25 per cent, which is the highest 

 of any month. The average for the year is 3.77 per cent. As might 

 be expected, the species are such as can be taken on the wing and do 

 not include such sedentary creatures as scales and plant lice. Stink- 

 bugs (Pentatomidse) and cicadas, with a few assassin bugs (Redu- 

 viidae), make up the bulk of tins item. 



Diptera (flies) are eaten by the kingbird in only moderate quan- 

 tities, though they appear in the stomachs of eveiy month except 

 the one taken in October. The maximum percentage, 8.36, occurs 

 in May, and the average for the year is 3.19 per cent. They belong 

 to several families, but one is of especial interest in relation to the 

 kingbird and honeybees. Tins is the family of the robber flies 

 (Asilidse), most of which are large, long-bodied, hairy creatures that 

 fly with a loud, buzzing sound and are usually seen about flowers in 

 bright sunshine, preying upon the insects that come to the flowers for 

 honey. They might bo thought to be useful insects were it not for 

 the fact that some species have a special liking for honeybees, which 

 they kill in considerable numbers. The late Dr. Riley states that 

 one species (Promaclius fitcliii) has been known to kill 141 honeybees 

 in a single day. Mr. T. J. Parrish, writing from Gainesville, Tex., in 

 1886, refers to robber flies as follows: 



The kingbird does nol feed upon bees, but an insect about three limes as large as 

 the bee, which carries off honey-laden bees, kills them, and appropriates the honey. 

 It is a hump-backed, long-tailed, spider-legged monstrosity, of rapid flight, and appears 

 in July and August. 



Prof. A. J. Cook, a well-known authority on bees, in an article on 

 the natural enemies of the honeybee, speaks of these flies as follows: 



Among Diptera the family Asilidse (robber flies) afford the most serious pests t<> the 

 apiarist * * *. There are at least 3 species of Asilus, 2 of Mallophora, 2 of Proma- 

 clius, 2 of Laphria, and 2 of Erax that catch and kill bees. These predaceous flies 

 work the most serious mischief south, but are not exempt from blame even as far 

 north as Ontario. 1 



» American Naturalist, XV, p. 200. 1881. 



