88 FIRST ANNUAL REPORT OF THE STATE ENTOMOLOGIST. 



ticular food-plant, upon which, up to that time, it had only been ob- 

 served : it is, however, now known to occur upon the pine and hem- 

 lock, and will doubtless be met with upon other of the evergreens. 

 The designation of lappet is borrowed from English writers who have 

 employed it for those caterpillars which are characterized by lappets or 

 leg-like appendages, placed in line on their sides, from which many 

 long hairs are given out, which nearly or entirely conceal the legs by 

 forming a lateral fringe to the flattened body. 



Protective Mimicry. 



The generic name of Planosa, meaning, in the Greek, a deceiver, 

 which Dr. Fitch proposed for this species, referred to the deceptive 

 appearance which it presents in both its caterpillar and moth stages, 

 and which is a prominent characteristic of its associated lappet cater- 

 pillars. Dr. Fitch has so ably and so faithfully described this feature, 

 that we transcribe what lie has written : — 



"The modes by which nature has endowed many insects to enable 

 them to elude the search of birds and other enemies are truly wonder- 

 ful. Among the insects thus endowed, the lappet-moths and their 

 caterpillars have often excited the admiration of the curious. The lat- 

 ter, when in repose have the body flattened, somewhat like that of a 

 leech, and on each side of each segment projects a little lappet or flat 

 lobe. These lappets are pressed down upon the surface of the limb 

 on which the worm is at rest. The sides of the body are also 

 fringed with hairs which are similarly appressed to the limb. Thus 

 all appearance of an abrupt elevation or an interstice to indicate 

 the ends and sides of the worm is obliterated, and it resembles 

 merely a slight swell of the natural bark, the deception being made 

 complete by the color, which is commonly identical in its hue with 

 the bark. And when there are spots or marks upon the caterpillar, 

 they imitate the glandular dots, scars, and other discolorations which 

 will be seen upon the bark around it. Even upon the closest scrutiny, 

 the eye fails to detect any thing by which we can be assured this eleva- 

 tion is not a tumor which has grown in the bark. * * * * 

 The cocoons which they construct upon the limbs are equally exact 

 counterfeits of the bush. One of these upon a limb of the wild black 

 cherry is now in the museum of the State Agricultural Society. It is 

 placed longitudinally in the slight angle formed exteriorly where one 

 limb branches from another, and a piece of putty could not be more 

 perfectly moulded into this angle and smoothed off so as to leave no 

 inequality. The bark of the cherry is blackish with transverse whitish 

 streaks, and this cocoon presents the same colors and of tints almost 



