1(105 



and far sliar[)ei' than in the green field. In (lie central window 4 

 of these arched stripes are present, in the back one 2. 



Comparison with SrnerintJnis populi and ocellata as well as so 

 many other .Spliingides, whose gronnd-colonr is brown or grey, and 

 whose transverse bands are composed of curved, stripy spots, leads 

 to the supposition tliat in these windows we have to see remnants 

 of the original hue and design of the wing, which for the rest has 

 become indistinct by green discoloration. 



As in so many other cases, e. g. the Hepialids, green therefore 

 would be the secondary, brown the primary hue, the design having 

 partly get lost in the process of discoloration or at least having 

 greatly diminished in distinctness. But why these two brown windows 

 with their trelliswork of curved stripy spots have remained untou- 

 ched by this process, 1 cannot as yet explain. 



Contrasting with the almost homogeneous green hue of the fore-wing, 

 the hind one possesses a very showy and variegated pattern : two 

 jetblack bars standing out against a light yellow ground, bluish- 

 grey areas occurring at the front border between the black, a 

 brickred patch vicariating with two black strokes near the inner 

 margin, while at the outer one a small green field breaks the yellow. 



But the most remarkable point in this pattern are two darkbrown, 

 irregular, denticulate lines, starting at the hinder angle, and running 

 parallel to the outer margin along its posterior part, to pass into 

 the broad black bar at the hinder border of the small green tield. 

 These crooked lines represent the posterior part and the pupilla of 

 the eye-spot in the oceUata-gvov\\i among Smerinthidae, and form 

 the least-modified part of the hind-wing-pattern of Pliolus labrasiae. 



I think it highly probable, that this pattern has a protective signi- 

 ficance for the animal, just as well as the almost homogeneous green 

 hue of the fore- wings and of the body. The latter give protection 

 to the sleeping animal by making it hardly visible to enemies that 

 prey upon it, possibly the brown windows play their part in this 

 process of concealment, by breaking the anatomical lines of the 

 rather extensive wingfield. 



It certainly would be worth while to make the experiment, 

 whether the moth when disturbed in its sleep, suddenly displays 

 its hind- wings and so frightens its enemies away, or whether the 

 showy colour-composition, which thereby gets visible, has only the 

 meaning of a warning-pattern, announcing unpalatableness. 



Whatever may be the right interpretation, this pattern in any 

 case ought to be considered as a high and special differentiation of 

 the original one of the hind-wings, common to all Spliingides ; neither 



