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



matter were found in two stomachs ; in one a bit of a kernel of oats, in 

 the other a single seed of carrot. Both stomachs were taken in Cali- 

 fornia in August. At that time certain species of ants may be seen 

 harvesting the seeds of grass and other plants. It may be that a swal- 

 low picked up an ant carrying a seed and so got a bit of vegetable 

 food, especially as these birds eat a great many ants. In any caso 

 the vegetable matter must be recorded as a mere trace, and the whole 

 food rated as practically 100 per cent animal matter. 



Beetles constitute 10.57 per cent of the food, 1.46 per cent being of 

 useful species. The others were more or less harmful, but none have 

 attracted attention by their depredations, although several have at 

 times done much damage in isolated cases. In all, 24 species were 

 identified, but none of them are familiar. The violet-green swallow 

 has not yet come sufficiently in contact with agriculture to feed much 

 upon the insects that destroy the farmers' crops. 



Ants (9.42 per cent) were eaten from May to September. Most of 

 them were taken in the first three months, nearly two-thirds of them 

 in July. All of a series of six stomachs collected at Sunol, Cal., in 

 July were completely filled with ants. Wasps and bees (17.48 per 

 cent) are eaten in every month of the season except April. A number 

 of parasitic species were observed, as well as a few gallflies (Cy- 

 nipidee) , but no honey bees. 



Hemiptera constitute the largest item of food (35.96 per cent). 

 They are eaten in every month of the bird's stay in the North, the 

 fewest in March, the most in September (68.36 per cent). They were 

 selected from 12 different families, of which the Jassiclse, or leaf 

 hoppers, were the favorites, having been found in 25 stomachs. The 

 Capsidae, or leaf bugs, were found in - 23 stomachs, the other families 

 in a less number. Xo other species of swallow has eaten so large a 

 percentage of Hemiptera, and the value of this work can hardly be 

 overestimated. Of the 12 families of bugs eaten by the violet-green 

 swallow, all but 1 are plant eaters, and some, like the Jassidse, do a 

 great deal of damage every year ; those like the Psylliclse, the Mem- 

 bracidse, and the Aphididse are small insects but wonderfully prolific 

 and do an immense amount of mischief without attracting attention 

 until the harm is done. Birds that destroy these creatures are cer- 

 tainly doing good work. 



Diptera are apparently a favorite food of the violet-green, as of 

 other swallows. They are eaten in every month of the season, 

 especialty in the spring months, when they constitute nearly half 

 the food. From May they gradually dwindle to less than 2 per cent 

 in September. The total for the season is 19.36 per cent. The 

 great mass of it was of such soft-bodied insects that in many cases 

 it was impossible to make identifications more definitely than as to 

 order. Craneflies (Tipulidae) were identified in two stomachs. 



