18 



BULLETIN" 619,, U. S. DEPARTMENT OF AGRICULTURE. 



Grasshoppers, found in 13 stomachs collected in the two months 

 August and September, amount to a little more than 2 per cent in 

 each, an average of only 0.37 per cent for the year. This indicates 

 that the tree swallow does not seek grasshoppers, for 112 stomachs 

 were taken in August (the grasshopper month), and even a moderate 

 appetite for these insects would have been revealed by that number 

 of stomachs. 



Among various other orders represented in the tree swallow's food, 

 remains of dragonflies' (Odonata) were found in 25 stomachs, one of 

 which contained fragments of 10 individuals. It has been suggested 

 that grasshoppers are too large to be managed by such small birds 

 as swallows, but a bird that can successfully dispose of dragonflies 

 should have little trouble with grasshoppers. Both of these insects 

 have harsh, crisp wings and stiff legs, while the body wall is hard 

 and not easily crushed. Both have hard, stout jaws, which, remain- 

 ing in the bird's stomach, serve to show what kind of food has been 

 eaten. May flies (Ephemerida) were found in 11 stomachs. 



Spiders (Arachnida) were found in 3 stomachs. In one a swarm 

 of minute young ones, evidently newly hatched, constituted 99 per 

 cent of the food. This may indicate that spiders are not distasteful, 

 but hard to get. In one stomach was found a small piece of fishbone, 

 an unaccountable item in the food of the tree swallow. These various 

 items together amount to 4.64 per cent and close the food account. 



Summary. — In the food of the tree, or white-bellied, swallow one 

 point is prominent — in its vegetable food it has no relation to man. 

 Every item is wild and of no use. In its insect diet it destroys some 

 parasitic Hymenoptera, some carnivorous Diptera, and a few other 

 useful insects, but this fault it has in common with most other in- 

 sectivorous birds, and in common with them it is engaged in reducing 

 the great flood of insect life to a lower level. Let it be protected and 

 encouraged. 



Following is a list of the insects identified in stomachs of tree 

 swallows and the number of stomachs in which found : 



Lestes sp_ 

 Teitix sp_ 



ORTHOPTERA. 



HEMIPTBRA. 



Stictocephalus sp — 

 Blissus leucopterus 



Pamera sp 



Limnotrechus sp 



COLEOPTERA. 



Clivina sp 



Pterostichus sp 

 Amara sp 



coleoptera — continued. 



Platynus variolatus 



Casnonia pennsylvamca 



Agonoderus calif omicus 



Discoderus robustus 



Cnemidotas 12-pmictatus 



Bidessus afflnis 



Hydroporus sp 



Berosus striatus 



Helophorus lacustris 



Helophorus sp . 



Hydro bins mathewsii 



Sphceridium scarabmoides 



Cercyon sp 



Gryptopleurwm minutum 



Aleochara bimaculata 



