BIRDS OF PORTO RICO. 



87 



pus sp.), eaten by 29 of the birds, amount to 41 per cent of the food for the 

 period under consideration. They are found in the food of all the months 

 represented except December, though in July they amount to only 2.17 per cent. 

 As many as 400 of these beetles were eaten at a single meal, and several birds 

 had taken 200 or over. Near Aguadilla, in June, the swallows were capturing 

 large numbers for their young, carrying them in the back of the mouth and below 

 the tongue in a well-moistened mass. Other snout beetles amount to only 1.19 

 per cent, but were all small species. Cane shot-hole borers (Xyleborus sp.), of 

 considerable damage in cane fields and also known to injure the shade trees of 

 the coffee (Inga vera and J. laurina), were found in seven stomachs. Few 

 beneficial species were destroyed. Rove beetles (Staphylinidse), which feed 

 upon decaying vegetable and animal matter, were eaten nine times, and lady- 

 bird beetles four. Together these form but 1.31 per cent, a small amount when 

 compared with the large bulk of snout beetles consumed. Sap-feeding beetles 

 (Nitidulida?), eaten by eight birds, and water scavenger beetles, detected in five 

 stomachs, together with indeterminate fragments of others, make 4.77 per cent. 



Flies (16.07 per cent) were eaten regularly and occur in 20 stomachs; ants in 

 17 stomachs amount to 9.13 per cent. The latter were taken from clouds of 

 males and females on their mating flights, and the numbers then destroyed 

 mean more than when individual workers are eaten, as each queen may be con- 

 sidered the nucleus of a new colony. Miscellaneous Hymenoptera make up 2.67 

 per cent. A moth was found in one stomach. The stomachs of two adults con- 

 tained bits of snail shell and gravel, and the stomach of a nestling taken in a 

 cave contained a rough angular bit of gravel of good size. Very few beneficial 

 insects are taken, the great bulk of the food consisting of directly injurious 

 species. As the birds feed in loose flocks over a large expanse of territory 

 they must exert considerable influence where found, and where insects are 

 abundant they congregate to feed upon them. 



From the foregoing it can readily be seen that the cliff swallow is one of 

 the best friends of the agriculturist. Should the bird modify its breeding habits, 

 as it now does in a few places, so as to resort to buildings erected by man 

 rather than to caverns, every encouragement should be offered it and the nests 

 should in no case be molested. Many believe that swallows bring vermin in 

 their nests, but it is firmly established that man's parasites are not borne by 

 our avian friends, and in case of unwelcome visitations the blame must rest 

 elsewhere. 



The following insects were identified in the stomachs examined : 



HBMIPTEEA. 



Ormenis sp 3 



COLEOPTEEA. 



Copelatus sp 2 



Berosus sp 2 



Cercyon sp 1 



Cycloneda limbifer 3 



Stelidota sp 1 



Photinus vittatus 1 



Cryptocephalus sp 13 



Cryptocephalus pusio 2 



Myochroas sp 1 



Haltica sp 2 



Epitriw parvula 4 



Systena sp 1 



Systena basalis 7 



Gerotoma denticornis 4 



Coptocycla signifera 1 



colboptera — continued. 



Euscepes porcellus 1 



Oaulophilus sp 1- 



Platypus sp 29 



Baris torquatus 1 



Tychius sp 1 



Xyleborus sp 2 



Xyleborus inermis 5 



DIPTEEA. 



Eristalis alMceps 3 



HYHENOPTEBA. 



Cardiocondyla venustula 1 



Prenolepis sp 1 



Ponera opaciceps 1 



Wasmannia auropunctata 2 



