o64 ' HENRY SHIMER, M. D. 



fore, are terminated at the extremity by four finger-like organs, — are 

 split up into four parts, the lower pair of digituli appearing farther 

 back by virtue of the obliquity of the extremity of the tarsi. These 

 are the only organs of prehension or locomotion, the claw being so un- 

 developed as to be useless, so far as I could learn from the living ani- 

 mal in every possible field of view under the microscope. Indeed, I 

 am not able to see any claw-like organ, in even the most imperfect 

 state of development, on any part of the foot, although I tried faith- 

 fully, by crushing the insect in every possible manner, so as to bring 

 the foot into every view in the field of the microscope; yet, reasoning 

 from analogy, we can hardly believe that it is without ungues ; but. 

 scientifically, how can we assign a place to a thing that cannot be seen? 

 for in anatomy we can only know by seeing. 



Ante7inse with about seven joints, five subequal, the last two smaller, 

 terminated by two short branches, or forking into two parts ; two spines 

 on the distal end of the fifth joint, about as long as one of the joints ; 

 color same as that of the body and legs. 



At 3 o'clock, P. M., I went to a cool cellar and brought out an ap- 

 ple limb that I had deposited there in the morning, well stocked with 

 young Bark-lice ; they were all quiet — no signs of a change into the 

 scale-like state ; they had the same pale yellowish-white appearance, 

 with an orange-yellow spot near either extremity, as observed this 

 morning; they were all motionless, but after a few minutes' exposure 

 to the warmth of the outside atmosphere, they begun to move as they 

 were doing in the morning. I then went to the orchard, and found 

 more than one-half of the lice located, many of them already presenting 

 a very complete scale-like appearance; others were but just locating, 

 and yet capable of moving their limbs, 



The transformation from the moveable to the fixed or scale-like state, 

 after anchoring themselves by the proboscis to the bark, is efl'ected by 

 the operation of moulting or shedding their skins, which must be done 

 by rupturing it either along the sides or beneath, for at this time the 

 scale can be removed, and the free insect can be isolated beneath in a 

 memberless state. I carefully detatched some of these insects, and, by 

 microscopic examination, could detect the form of an independent be- 

 ing, but no motion. In those most recently moulted, I can plainly see 

 the legs, even the digituli in the skins, but in somewhat of a curled 

 or distorted condition, and in a little while they become fully dry, 

 when they are found to have lost all trace of their limbs and former 

 appearance. 



