38 OY8TEK-8HELL BAEK-LOrSB. 



The egg thus deposited batches into the little footless larva pre- 

 viously mentioned. This larva is so admirably described by Dr. 

 Fitch, in a single sentence, that I cannot do better than copy his 

 description : " Under these scales 1 have repeatedly met with a 

 small maggot, three-hundreths of an inch long, or frequently 

 much smaller, of a broad oval form, rounded at one end and taper- 

 ing to an acute point at the other, soft, of a honey-yellow color, 

 slightly translucent and shining, with an opaque brownish cloud 

 in the middle, produced by alimentary matter in the viscera, and 

 divided into segments by tiaintly impressed transverse lines." 



The only motion of which this small grub is capable is a slight 

 extension and contraction of its body, particularly at the two 

 extremities, by which its form is correspondingly modified. 



There is usually but one larva under each scale, and I have 

 never seen more than two. in the earlier part of the season it is 

 seen adhering to the body of the Bark-louse, but later it is found 

 in the midst of the eggs or their remains. 



The Chalcis-fiy itself is a beautiful object under the microscope. 

 Its length is a little less than half a line, or about one-twenty-fifth 

 of an inch, though I have captured a few specimens considerably 

 smaller, being but little more than one-third of a line, I at first 

 supposed that these smaller individuals were males, but all the 

 s})ecimens that I have examined have proved to be females. Their 

 color is a uniform pale lemon yellow. The only variation from 

 this color is in the minute mandibles, which are reddish brown. 

 There are three coral red occelli on the summit of the head, and 

 the ovipositor, which lies in a groove on the underside of the abdo- 

 men, exhibits a slight reddish tint. The wings are thickly beset, 

 over nearly their whole surface, with bristly points, and their mar- 

 gin is ornamented with a long fringe. 



But a better idea of the appearance of this little insect will be 

 obtained from the magnified figures which accompany this article, 

 than from any verbal description. 



By observations, made as late as the first week in ]!^ovember, 

 the opinion is confirmed that the Chalcis of the Bark-louse has 

 two broods in a year. By the middle of September we find many 

 of this year's scales pierced with the round holes through which 

 the first brood of Chalcides has escaped ; and late in the fall we 

 find, under about an equal number of scales, the fully-grown larvae 



