88 FIFTH ANNUAL REPORT 



in his own words; especially as I have had no opportunity of making 

 personal observations upon it. It belongs to the extensive family 



GhalGididce^Vihioh com- 

 prises insects of small size, 

 characterized chiefly by their 

 jumping power and parasitic 

 habit. The species in ques- 

 ■^\'\ tion was described { Amer. 



Ent. ii> p. 360) under the name of Aphelinus mytilaspidis from the 

 female sex only, the male being yet undiscovered. Her habits are 

 thus recorded by Dr. LeBaron : 



In the course of a series of observations upon the Apple-tree 

 Bark-louse, during the past season, it has been my good fortune to 

 trace the history of this interesting little insect, w^hich, if it has ever 

 been seen before, has not been identified, and whose very existence 

 has been only a matter of inference from the visible marks of its 

 beneficent operations. 



In the early part of the season, while examming the lice upon an 

 apple tree, I noticed two or three little yellov*?^ Chalcides running along 

 the infested twigs, which I conjectured might be the parasites of the 

 Bark-louse, but had no proof that this was the case. But about the 

 first of August, upon raising one of the scales, I happened to uncover 

 one of these insects in the last stage of its transformation. Its wings 

 were not yet unfolded, but it ran so rapidly that I had some difficulty 

 in keeping it within the field of the lens. As soon as it paused long 

 enough to be examined, it was easily recognized as a Chalcis by its 

 general aspect, and especially b}'^ the peculiar vibratile motion of its 

 short geniculate antennas. 



Having once become familiar with its appearance, I have had no 

 difficulty in capturing, in the latter part of August and September, 

 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 transverse!}'' with 

 respect to the scale. Sometimes sh6 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 so far as to bring the 

 tip of her abdomen about opposite the middle of the scale. Then 

 bringing her ovipositor down perpendicular to her body, she forces it 

 through the scale by a series of boring or short plunging motions. 

 Having accomplished this, she remains stationary for many minutes, 

 while by some invisible intestine motion the egg, is carried down the 

 ovipositor and deposited beneath the scales. So absorbed is she in 

 this delicate operation, upon the successful accomplishment ot^ 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 CIioIgis in the 

 act of depositing. While 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 drawing down the limb the third 



