BIRDS IN RELATION TO THE ALFALFA WEEVIL. 39 



Two others had eaten the weevil, and in one of these 12 adults 

 formed one-half of the contents while 5 adults and 29 larvae in 

 the stomach of the other composed 99 per cent of the food, a single 

 seed of dandelion being the only other ingredient. The former of 

 these had fed also on a cicada, a grasshopper, an ant, and a little 

 grain. The lazuli bunting, aside from its esthetic value, is a bird 

 of considerable economic importance. The products of the . farm 

 seldom enter into its diet, while among its customary food may be 

 found the seeds of troublesome weeds and many noxious insects, 

 including the alfalfa weevil. 



CLIFF SWALLOW. 



(Petrochelidon lunifrons lunifrons.) 



With the exception of the rough-winged, the cliff swallow is the 

 most abundant swallow in the territory covered by the present in- 

 vestigation. As enemies of the alfalfa weevil the most effective 

 work of this and other swallows almost continuously on the wing 

 is either at the time of the spring flight of the weevil or when the 

 brood of the year takes wing later in the season. 



Twenty stomachs of the cliff swallow were examined, three of 

 which were of adults and the rest nestlings. The adults were col- 

 lected early in June, when the birds were engaged in nest building 

 and their stomachs contained 2, 6, and 8 adults, respectively, 

 which formed about 12 per cent of the contents. Ground beetles 

 composed over 40 per cent of the food. Besides these were found 

 fairly large amounts of Hemiptera (bugs), Odonata (dragon flies), 

 and aquatic, scarabseid, and other beetles. 



In the stomachs of 17 nestlings collected later in the month the 

 weevil formed but a part of 1 per cent of the contents, and was 

 present in 7 of the 17 stomachs. In only one, however, did this insect 

 occur in considerable numbers, that of a nestling about a week old 

 which had been fed 21 adults. Another had eaten 5, and a third, 3. 



As these birds were not far distant from extensive marshy areas, 

 large quantities of the small aquatic beetle (Helophorus lineatus) 

 were found in their stomachs. These had been eaten by each of 

 the nestlings and formed about a sixth of their food. As many as 

 50 of these beetles were found in a single stomach. A small black 

 ant occurred in each of the stomachs, in some cases in surprisingly 

 large numbers, and in bulk it comprised a little over half of .the 

 young cliff swallows' food. The remains of flies of several species 

 formed over a fourth of the stomach contents. 



The work of all swallows upon the alfalfa weevil is confined to the 

 two flight periods of the adult insect. During the earlier flight, when 

 the life of the weevil is at its lowest ebb, any reduction of its num- 



