106 BULLETIN 326, U. S. DEPARTMENT OF AGRICULTURE. 



Food. — The 63 stomachs collected show nothing but animal matter (100 per 

 cent). These represent the food from January to August, inclusive, in Porto 

 Rico, Vieques, and Culebra Islands. 



This species may be listed among the bird enemies of the mole cricket 

 (Scapteriscus didactylus) , as an adult male collected at the Laguna de Guanica 

 on May 26 contained in its stomach a mandible and other remains of a changa. 

 Other orthopteran remains (7.21 per cent) were present in 14 stomachs. Lan- 

 tern flies (Fulgoridse), present in this species again in large numbers (17.6 per 

 cent), were detected in 28 stomachs. Other Homoptera (7.24 per cent) were 

 largely cicadas (Proarno Mlaris). Other bugs, partly predacious, though two 

 stinkbugs and a few bug eggs are included, amount to 3.03 per cent. Longicorn 

 beetles (2.7 per cent) were present in 5 stomachs, while small leaf-beetles (1.88 

 per cent) were taken 12 times. Two species of flea beetles (Systena basalts 

 and Clmtocnema sp.) were each taken by two birds. Small beetles of this 

 group are found to be injurious almost invariably to some of the vegetables 

 grown in fields and gardens. Click beetles (4.96 per cent) were great favorites 

 in the mangrove swamps, and among the weevils (1.21 per cent) may be men- 

 tioned a shot-hole stalk-borer (Xyleborus sp.). Fireflies come to 1.99 per cent 

 and miscellaneous Coleoptera to 1.88 per cent. 



Diptera (8.16 per cent) were present in 16 stomachs, in one case a flesh fly 

 (Compsomyia macellaria) that deposits its eggs in sores or injuries in the flesh 

 of living animals, or even in the nostrils of man. The larvse, known as screw 

 worms, are much dreaded, especially in tropical countries, as in many cases 

 their attack is known to be fatal. That this bird is active in the pursuit of 

 insects is attested by the fact that moths were eaten by 18 birds, and these with 

 caterpillars taken by 9 birds amount to 11.95 per cent. Ants make up 0.58 per 

 cent and other Hymenoptera 8.72 per cent. These last were contained in 26 

 stomachs and were largely small insects of parasitic habits. A species of 

 Kapala, which infests ants, was taken once and indeterminate chalcids were 

 noted three times. A peculiar sawfly, with two-branched antennae, was found 

 in one stomach. Spiders (18.07 per cent) were eaten constantly and appear 

 in 31 stomachs. Two dragon flies and two earwigs with a small portion of mis- 

 cellaneous matter form the remainder (2.57 per cent). 



In the foregoing outline of the food of this bird it will be seen that approxi- 

 mately 28 per cent of the bulk is made up of insects of a more or less beneficial 

 nature, as spiders, parasitic Hymenoptera, dragon flies, and some bugs. Against 

 these, however, stand the 70 per cent and more of other insects consumed, prac- 

 tically all of harmful species. Among these are some great pests, the lantern 

 flies, nearly all of the beetles, Lepidoptera, and others. Thus the yellow 

 warbler is one of man's friends. 



The following insects were identified in these stomachs : 



ORTHOPTERA. 



Scapteriscus didactylus 1 



HEMIPTERA. 



Ormenis sp 11 



Proarno hilaris 3 



COLEOPTERA. 



Scymnus roseicollis 1 



Cryptorhopalum sp 1 



Monocrepidius sp 8 



Pliotinus vittatus 3 



Photinus glaucus 2 



Leptostylus sp 2 



coleoptera — continued. 



Cryptocephalus sp 8 



Myochrous sp 1 



Systena oasalis 2 



Chcetocnema sp 2 



Mordellistena sp 1 



Xyleborus sp - 1 



DIPTERA. 



Compsomyia macellaria 1 



hymenoptera. 



Kapala sp 1 



