OYSTEE-SHELL BARK-LOTJSE. 37 



rapidly that I had some difficulty in keeping it within the field ot 

 the lens. As soon as it paused long enough to be examined, it 

 was easily recognized as a Chalcis by its general aspect, and espe- 

 cially by the peculiar vibratile motion of its short, geniculate 

 antennte. 



Having once become familiar with its appearance, I have had 

 no ditiiculty in capturing, in the latter part of August and Septem- 

 ber, all the specimens I desired on the infested trees, I have 

 repeatedly watched the female Chalcis in the act of inserting her 

 ovipositor through the scale of the Bark-louse, for the purpose of 

 depositing her egg in the cell beneath. She always places herself 

 transversely with respect to the scale. Sometimes she mounts 

 upon it, and then her tiny body is seen to be considerably less in 

 length than the width of the scale. Usually she backs up upon it 

 only 80 far as to bring the tip of her abdomen about opposite the 

 middle of the scale. Then bringing her ovipositor down perpen- 

 dicular to her body, she forces it through the scale by a series of 

 boring or short plunging motions. Having accomplisned this she 

 remains stationary for many minutes, whilst by some invisible 

 intestine motion the egg is carried down the ovipositor and deposi- 

 ted beneath the scales. So absorbed is she in this delicate opera- 

 tion, upon the successful accomplishment of which not only her 

 own hopes, but those of the horticulturist, so largely depend, that 

 nothing can deter her from it. In one instance, having drawn 

 down a branch of an apple tree, I discovered a Chalcis in the act 

 of depositing. Whilst holding the branch in one hand and view- 

 ing the insect through a lens held in the other, the branch slipped 

 through my fingers and flew back with violence to its place. 

 Drawing it down again, the twig I had hold of broke, and it flew 

 back a second time. I supposed that that observation had, of 

 course, been brought to an abrupt termination. But, upon draw- 

 ing down the limb the third time, there stood my little Chalcis as 

 immovable as a statue, at her post. She may be touched with the 

 finger whilst thus engaged, or even crushed, as I have often inad- 

 vertently done in my attempts to capture her, but nothing short 

 of this actual violence can move her from her position. With such 

 wonderful perseverance and devotion do these living atoms of 

 creation perform their allotted part in the complicated economy of 

 nature. 



