THE FALL WEB- WORM. 251 



Chickens, and even the omniverous ducks, do not eat them ; if oflfered 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 what- 

 ever. Indeed, as before stated, its introduction and multiplication has greatly 

 favored the increase of the worms. 



The "pellets" of a Screech-owl {Scops asio) found in the vicinity of Baltimore, 

 Md., and examined by Mr. Luggar, consisted apparently almost 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 species, 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 (Biifo americana) has eaten great numbers of these caterpillars, 

 as shown by dissections made by Mr. Lugger, and it should be carefully protected 

 instead 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 

 obtaius 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, jumping 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 Atttis has similar habits, but is still more cautious ; 

 it usually hides under loose bark. Both spiders are wonderfully active, and kill large 

 numbers of caterpillars. Their large flat egg-masses can be found during the winter 

 under dead bark and in cracks. Both species hibernate in silken nests in similar 

 localities. 



Predaceous insect enemies. — The caterpillars of this moth have quite a number of 

 external enemies, which slay large numbers of them. The well-known Rear-horse 

 {Mantis Carolina, see Fig. 89) seems to be very fond of the caterpillars. The Wheel- 

 bug, Prionidus cristatus (Fig. 104), has proved to be one of our best friends in re- 

 ducing the numbers of the caterpillars. This insect was formerly by no means 

 very common in cities, but of late years it has greatly increased in numbers, and is 

 now a well-known feature in all our public parks and such streets as possess shade- 

 trees. Outside of the city it is rarely met with; nor does it extend much farther 

 north than Washington. It is, like the Mantis, in all its stages a voracious feeder 

 upon insect-:, slaying alike beneficial and noxious ones. The bright red larvae and 

 pupae, also carnivorous, are seen in numbers during the summer; they usually 

 remain together until hunger forces them to scatter. They assist each other in kill- 

 ing larger game, and are to this extent social. The Wheel bug could be observed 

 almost anywhere last summer, usually motionless, stationed upon the trunk of trees, 

 waiting for the approach of an insect. If one comes near, it quite leisurely inserts 

 its very poisonous beak, and sucks the life-blood of its victim. When this becomes 

 empty it is hoisted up in the air, as if to facilitate the flow of blood, until eventually 

 it is thrown away as a mere shriveled skin. The appetite of the Wheel-bug is re- 

 markable, whenever chances offer to appease it to the fullest extent. Frequently, 

 however, times go hard with it, and notwithstanding it is very loath to change a posi- 



