lOO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



of the arachnids captured for one meal were 20 by a yellow-billed 

 cuckoo and 'j'j by an ovenbird. 



Number of identifications, 10,885 ! percentage of identifications 

 among those of all arthropods, 5.1648; percentage of species in this 

 class among those of all arthropods, 3.8254. 



Other enemies. — Spiders are frequently snapped up by fresh-water 

 fishes, and mites often, especially the water mites. Pycnogonids, or 

 sea-spiders, have occasionally been found in the stomachs of marine 

 fishes and are consumed also by sea-anemones. Kirkland found 

 spiders to compose 2 per cent of the food of 149 common toads 

 examined by him, and Drake found them to constitute about 27 per 

 cent of the entire number of animals found by him in the stomachs 

 of 209 leopard frogs. However, practically all frogs, toads, and sala- 

 manders that have been studied have been found to feed upon spiders, 

 often extensively, and mites, pseudoscorpions, and phalangids are not 

 neglected. Lizards commonly prey upon spiders, while snakes and 

 turtles so far have rarely been observed to do so. 



Spiders appear to constitute an important element of the food of 

 our shrews, and a lesser, though frequently taken, item in the diet of 

 the moles. We have records of the wood rat and armadillo preying 

 upon spiders, and evidence that the badger at times is a destructive 

 enemy of scorpions. Monkeys and marmosets are said to be very fond 

 of spiders, and anteaters also are listed among their foes. 



Of invertebrate enemies various wasps ( Pompilidae. Sphegidae, and 

 Trypoxylonidae) are among the most efifective destroyers of spiders, 

 some species preying exclusively upon them, temporarily at least, even 

 upon single species. The writer has found the cells of Pclopaeus 

 cementarhis filled entirely with flower spiders, Misitrnena americana, 

 supposedly one of the most perfectly protected (cryptically colored) 

 species. Dragonflies prey upon spiders. Tiger beetles and ants eat 

 spiders and mites, ground beetles and ladybirds also figure as enemies 

 of mites and spiders. Water mites are preyed upon by dragonfly 

 nymphs and aquatic Hemiptera. There are a number of kinds of 

 spiders that habitually prey ui)on their fellows when adult, and canni- 

 balism among young spiders is the rule. Mantispidae and other 

 spiders eat the eggs and young of spiders, and there are many proc- 

 trotrupid and ichneumonid parasites of the eggs. Parasitic nematodes 

 also aftlict the adults. Scorpions are notoriously cannibalistic, so much 

 so in fact that it is said in some cases that whenever two of them are 

 found together, one is eating the other. 



