NO. 7 PROTECTIVE ADAPTATIONS McATEE 49 



Hampshire Agr. Exp. Sla., pp. 21-23, Feb., 1902). and the conchision 

 was drawn that " toads do not ordinarily devour many of these pests." 

 Perhaps they do not "devour many" of them, nor, with the whole 

 insect world available for them to prey upon, should they be expected 

 to specialize upon squash bugs, but they do eat them, as found by 

 Kirkland (Bull. 46, Hatch Exp. Sta., p. 26, 1897) and also by 

 Biological Survey investigators. Bird enemies also are not lacking, 

 present records showing six species of birds known to feed upon 

 Aiiasa trisfis and four upon other species of the genus. The harlequin 

 bivg is sometimes heavily parasitized also, while the squash bug has 

 both tachinid and hymenopterous parasites and is subject to a bacterial 

 disease. 



Disregarding the " protective adaptations " and reasoning alone 

 from the prevalence of hemiptera, there would be no presumption 

 that these insects would constitute a tenth of the food of any species 

 of birds, yet they actually do contribute 10 per cent or more of the 

 subsistence of the following 12 species in the United States: Nuttall 

 woodpecker (numl)er of stomachs examined 53), percentage of 

 Rhynchota in the food, 14.76 per cent ; Scissor-tailed flycatcher (129), 

 10.17 per cent; eastern phoebe (370), 10.38 per cent; black phoebe 

 (344), 10.56 per cent; crested flycatcher (265), 14.26 per cent; least 

 flycatcher (177), 11. 12 per cent; Bullock's oriole (162), 10 per cent; 

 sharp-tailed sparrow (51), 12 per cent ; spotted towhee (139), 14 per 

 cent; purple martin (205), 14.58 per cent; barn swallow (467), 

 15. 1 per cent ; and rough-winged swallow (136), 14.9 per cent ; more 

 than 20 per cent of the food of two birds, namely the black-headed 

 grosbeak (225), 21 per cent, and cliff swallow (375), 26.32 per cent, 

 and more than 30 per cent of the total diet of the violet-green swallow 

 (no), 35.96 per cent. 



If the glandular secretions of hemiptera had the repugnatorial, not 

 to say dangerous, qualities attributed to them, there would be no such 

 wholesale preying upon them as is shown in the foregoing data. 

 Descending to milder forms of " protection " as afforded by pointed 

 protuberances and secretions of wax, we find that the " hardihood " 

 of birds (from the selectionist point of view), or in other words their 

 tendency not to be bound by human criteria, is so great that such 

 devices simply do not count. 



NEUKOPTKKOIDKA (dOBSONFMES, SNAKEFLIKS, SfOIU'ION FLIES, ANT-LIONS, 

 CADDISFLIES) 



In the period during which the records of bird food here discussed 

 were obtained, the conception of the group of insects broadly termed 

 Neuroptera has gradually evolved from that of a catch-all for net- 



