46 OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 



result often follows summer denudation by any insect, and we have re- 

 ferred to some remarkable cases in our previous writings.* 



ENEMIES OF THE WEB-WORM OTHER THAN INSECTS. 



"The caterpillars have comparatively few enemies belonging to the 

 vertebrate animals. This is not owing to any offensive odor or to any 

 other means of defense, but is entirely due to their hairiness. Chick- 

 ens, and even the omnivorous ducks, do not eat them; if offered to the 

 former they pick at these morsels, but do not swallow them. 



"The English sparrow has, in this case at least, not proven of any 

 assistance whatever. Indeed, as before stated, its introduction and 

 multiplication has greatly favored the increase of the worms. 



"The 'pellets' of a Screech-owl (Sco2)s asio) found in the vicinity of 

 Baltimore, Md., and examined by Mr. Lugger, consisted apparently al- 

 most entirely of the hairs of these caterpillars, proving that this useful 

 bird has done good service. 



"Perhaps the statement may be of interest, that this little owl is 

 getting much more common in the vicinity of such cities, in which the 

 English sparrow has become numerous, and that the imported birds 

 will find in this owl as bold an enemy as the Sparrow-hawk is to them 

 in Europe, and even more dangerous, since its attacks are made towards 

 dusk, at a time when the sparrow has retired for the night and is not 

 as wide awake for ways and means to escape. 



" If our two cuckoos, the black-billed as well as the yellow-billed spe- 

 cies, could be induced to build their nests within the city limits or in 

 our parks, we should gain in them two very useful friends, since they 

 feed upon hairy caterpillars. 



"The common toad (Bufo americana) has eaten great numbers of 

 these caterpillars, as shown by dissections made by Mr. Lugger, and 

 it should be carefully protected iustead of being tormented or killed by 

 boys or even grown people. The toad is always a useful animal and 

 ought to be introduced in all gardens and parks. 



"The following species of spiders were observed to eat the caterpillars, 

 viz, Marpessa undata Koch and Attus {Phydippus) tripunctatus. Neither 

 species builds a web, but obtains its prey by boldly leaping upon it; 

 they are, in consequence of such habits, frequently called Tiger-spiders. 

 The former was exceedingly common last year, more so than for many 

 previous years, thus plainly indicating that the species did not suffer 

 for lack of food. This species is usually found upon the trunks of trees, 

 and is there well protected by its color, which is like that of the bark. 

 It hides in depressions and cracks of the bark, and, jumpiug upon the 

 passing game, or, cat-like, approaching it from behind, it thrusts its 

 poisonous fangs into the victim, which soon dies and is sucked dry. 

 The Attus has similar habits, but is still more cautious; it usually hides 



* See Eighth Report ou the Insects of Missouri, p. 121. 



