216 BULLETIN OF THE BUREAU OF FISHERIES. 
American species may possibly eat more Hymenoptera than we are aware. ‘Termites, 
winged ants, and cicadas are also interesting victims of the odonata which have been 
recorded in other parts of the world. A dragonfly is reported to have dug a cricket out 
of the ground and eaten it (Habit of a Dragonfly, editorial notes, Psyche, vol. 5, p. 364), 
but this is the only instance, so far as known, where odonates have eaten any of the 
Orthoptera. 
S1zE OF PREy.—Perhaps the food of the damselflies is usually made up of smaller 
insects than that of the dragonflies, but the size of the prey is not always in proportion 
to the size of the imago that eatsit. A¢schna and Anax, two of our largest dragonflies, 
are among the most persistent eaters of gnats, midges, and mosquitoes, while one of the 
favorite foods of the damselfly, Argia mesta putrida, is a black mayfly almost as large as 
itself. Like that of the nymphs, the appetite of the imago seems weli-nigh insatiable, 
and no sooner is one insect devoured than another is caught. Stories of the amount 
eaten by some imago are told by nearly every observer, and the present author would 
add one more to the list. A male A. m. putrida was given eight black mayflies, one 
after the other, and he ate every one of them, simply throwing away the legs and wings; 
yet any two of them exceeded in bulk the damselfly’s whole body, minus its wings and 
legs. 
SourcsE oF Foop Suppry.—The food is usually captured in greater or less proximity 
to the water, sometimes being picked off the very surface of the latter. However, the 
female dragonfly habitually hunts at a greater distance from the water than the male. 
The females of Plathemis lydia and Perithemis domitia are only rarely seen around the 
ponds. The females of other species come to the water for the purpose only of laying 
their eggs, while the males are constantly patrolling the surface of the ponds, as well 
as the banks in the immediate vicinity. 
Even the males, however, do not obtain all their food near the water. Anax, 
Zischna, Libellula pulchella, Tramea, and Epicordulia make long foraging trips out into 
the surrounding country and are often found a considerable distance from any body of 
water. In this way they help to rid the countryside of some of its worst insect pests, 
especially flies, mosquitoes, gnats, and midges. Such foraging trips are made more 
often late in the afternoon, toward sunset, and sometimes after. The males, and 
occasionally a female, of many of the species around the ponds came regularly every 
evening to the laboratory building and hawked for food. They picked flies off the 
window screens and the sides of the building, they decimated the hordes of gnats and 
midges that swarmed in the waning sunshine, and sometimes they ascended high in the 
air in search of the tiny insects to be found there. Occasionally their hunting was 
prolonged after sunset, when the insects were particularly numerous, Lzbellula luctuosa 
was the most common of these visitors, but they also included Erythemis, Leucorrhinia, 
Plathemis, T'ramea, Pantala, Anax, Ajschna, and even Gomphus vastus and G. fraternus. 
MIGRATION OF ‘TENERALS.—As soon as possible after emerging the teneral imagos 
of Libellula luctuosa fly back onto the prairie, away from the ponds and the river. There 
they remain in the gullies and among the underbrush until they become ready for 
pairing and egg laying... A trip of a mile or two up some of the gullies leading back onto 
the prairie will reveal thousands of these tenerals roosting on the weeds and underbrush. 
Occasionally an imago of Erythemis, Leucorrhinia, some Gomphus species, or an 
Enallagma will be found with them. Usually there is no water within reach, but if 
