SWALLOWS. 99 
been informed, bee keepers do not regard the destruction of drones as 
injurious to the swarm. In most cases drones are superabundant 
air instead of contributing to the food supply they are a drain upon 
itso that the destruction of some of the surplus males is a positive 
benefit to the colony. 
Hemiptera, or bugs, stand next to Hymenoptera in importance in 
the food of the cliff swallow. They form a little less than 27 percent 
of the whole diet, and are represented by eight families, namely, 
assassin-bugs, leaf-bugs, squash-bug family, stink-bugs, shield-bugs, 
tree-hoppers, leaf-hoppers, and jumping plant-lice. All of these, 
excepting the assassin-bugs, are injurious to plants, and some of them 
are pests at all times. Of these, probably the leaf-hoppers (Jasside) 
are the worst. They suck the juices of plants, particularly grasses, 
which they infest by millions. They are said to have but few enemies, 
of which birds are the most effective. It is probable that they are 
captured by swallows when just skimming over the surface of fields, 
or are snatched from the tops of grass and weeds. They were found 
in 27 stomachs. 
Leaf-bugs (Capside) are a very large family of harmful insects, 
which feed almost entirely upon plants. Some species of this family 
are pests of the worst description. Leaf-bugs were contained in 43 
stomachs. The other insects of this order are more or less harmful, 
but were not eaten so extensively. 
Beetles of all kinds aggregate a little less than 19 percent. Of 
these, 2 percent were useful species, such as carabids and coccinellids. 
The others belong to 12 different families, most of which are harmful, 
some very much so. Among them were a number of aquatic species. 
These were probably captured by the swallows when fying just above 
the surface of the water. The principal flights of beetles do not 
occur during the day, but chiefly in early evening and at night. 
Flies are eaten by cliff swallows to the extent of nearly 12 percent 
of the food. Most of these are the species commonly known as 
gnats, but one stomach contained a large horsefly (Tabanide). The 
gnats have a habit of swarming afternoons and evenings, when many 
are probably snapped up by swallows. 
The remains of dragon-flies, lace-winged flies, ephemerids, and 
spiders make up the rest of the food, or a little more than 3 percent. 
As spiders do not fly, it may be asked how they were captured by 
the swallows. They probably were snatched from their webs or from 
the tops of weeds as the birds passed. Swallows pick up substances 
even from the ground, as is shown by the vegetable component of 
their food, and by other facts to be given presently. 
@ Plant-lice and scale-insects were not present, and this may be explained from 
the fact that their lives are passed mostly in a wingless condition. 
