48 



OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 



however, times go hard with it, and notwithstanding it is very loth to 

 change a position once taken, it is sometimes forced to seek better hunt- 

 ing grounds, and takes to its wiugs. The Wheel-bug has been observed 

 toremaiu for days iu the same ill-chosen position, for instance upon the 

 walls of a building, waiting patiently for something to turn up. It is 

 slow in all its motions, but withal very observant of everything occur- 

 ring in its neighborhood, proving without doubt great acuteness of 

 senses. It does not seem to possess any enemies itself, and a glance at 

 its armor will indicate the reason for this unusual exemption.* During 

 warm weather this bug possesses a good deal of very searching curi- 

 osity, and a thrust with its beak, filled with poison, is very painful in- 

 deed. Boys call it the Blood-sucker, a misnomer, since it does not 

 suck human blood. The eggs are laid during the autumn in various 

 places, but chiefly upon smooth surfaces of the bark of tree-trunks, and 

 frequently in such a position as to be somewhat protected against rain 

 by a projecting branch. The female bug always selects places the 

 color of which is like that of the eggs, so they are not easy to see, not- 

 withstanding their large size. 



" Euschistus servus Say, is another hemipterous insect that preys upon 

 the caterpillar of R. mtnea, and in a similar manner to the Wheel-bug. 

 It is a much smaller, but also a very useful insect. 

 "Podisus spinosus Dall.(Fig. 21), in all its stages was quite numerous 



dining the caterpillar plague. 



Its brightly-colored larvae and 



pupse (Fig. 22) were usually 



found in small numbers to- 

 gether ; but as they grew older 



they become more solitary in 



their habits. All stages of this 



insect frequent the trunk and 



branches of trees, and are litere actively engaged in 



feeding upon various insects. As soon as oue of 

 the more mature larvas or a pupa has impaled its prey, the smaller 

 ones crowd about to obtain their share. But the lucky captor is by no 

 means willing to divide with the others, and he will frequently project 

 his beak forward, thus elevating the caterpillar into the air away from 

 the others. The habit of carrying their food in such a difficult position 

 has perhaps been acquired simply to prevent others from sharing it. A 

 wonderful strength is necessary to perform such a feat, since the cater- 

 pillar is sometimes many times as heavy as the bug itself. The greedi- 

 ness of this bug was well illustrated in the following observations: A 

 pupa of P. spinosus had impaled a caterpillar, and was actively engaged 

 in sucking it dry; meanwhile a Wheel-bug utilized a favorable oppor- 

 tunity and impaled the pupa, without forcing the same to let go the 



* The eggs of the Wheel-bug are pierced, however, by a little egg-parasite— Eu- 

 pelmus reduvii Howard. 



FlG. 21.— Podisus spi- 

 nosus : «, enlarged 

 beak ; b, bug, with right 

 ■wings expanded. 



Fig. 22. — Podisus spino- 

 sus: a, pupa; b, larva; c, 

 egg. 



