526 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



getting m-ach more common in the vicinity of sncli cities in which 

 the English Sparrows have 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 (Bufo 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 caterpil- 

 lars, viz, Marpessa undata Koch, and Attus {Phydippus) tripunc- 

 tatus. 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, jumping upon the passing game, or, catlike 

 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 under loose bark. 

 Both spiders are wonderfully active and kill large numbers of cater- 

 pillars. Their large and 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 caterpilla-rs of this moth have quite a number of external en- 

 emies, which slay large numbers of them. The well-known Rear- 

 horse {Mantis Carolina) seems to be very fond of the caterpillars. 

 The so-called Wheel-bug (Prionidus cristatus) has proved to be one 

 of our best friends in reducing 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 jSTorth than Washington. It is, like the Mantis, in all its 

 stages a voracious feeder upon insects, slaying alike beneficial and 

 noxious ones. The bright-red larvae and pupte, also carnivorous, are 

 seen in numbers during the summer; they usually remain together 

 until hunger forces them to scatter. They assist each other in 

 killing larger game, and are to this extent social. The Wheel-bug 

 could be observed almost anywhere last summer, but usually motion- 

 less, stationed upon the trunks of trees, waiting for the approach of 

 an insect. If one comes near, it quite leisurely inserts its very poison- 

 ous 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 



