1002 



belonging to different orders and that it may likewise be remarked 

 in the nervural system, which possesses snch intimate and primor- 

 dial relations to the distribntion of pigments in the skin. 



Were it only to considei* this qnestion from all possible points of 

 view, the well-fonndedness of the hypothesis would have to be tried, 

 whether net-design may be connected with the formation of meshes 

 in the system of wing-nervures, as is so frequently and specifically 

 found in Nenroptera and Orthoptera, vicariating with regular trans- 

 verse venation ; whether therefore the net-design may not be as old 

 as or even older than spots or stripes. An argument to this assertion 

 might be found in the fact, that nets between the longitudinal veins 

 are characteristic of the nervation of the wings in Palaeozoic 

 Palaeodictyoptera. 



With this inference I do not in the least intend to proclaim, that 

 I am convinced of this connection of the net-design and of its phy- 

 logenetic antiquity, but simply that I think the contraiy is not 

 proved either. 



Remembering Weismann's words: "Ohne Hypothese und Theorie 

 giebt es keine Natnrforschung", I am of opinion that the continual 

 proposing of explaining suppositions about the connection between 

 corresponding phenomena is necessary condition for fertile scientific 

 research, and therefore I cannot adhere to dk Mkykrk's point of 

 view, where he says: "Ich möchte mich, den Tatsachen entsprechend, 

 mit Feststellung des Auftretens begniigen und keine ganz hypothe- 

 tische Verbindungslinien ziehen." 



Returning to the specific differential characters of Sm. oceJIata, 

 I here find the danger to get entangled in purely hypothetical spe- 

 culations not by any means serious. For it can be easily proved 

 that all the special characteristics of the upper side of both fore- 

 and hind-wings occur as well in other species, not oidy of the genus 

 Smerinthus, but also of different allied genera. 



In the tii'St place the comparison with tiliae is highly instructive. 

 On the upper side of the fore-wing of the Limetree-Hawkmoth every 

 peculiarity by which the pattern of ocellata deviates from that of 

 popuH, is again met with, but in a modified form and in other 

 hues, which together produce a totally different effect of the wing- 

 design as a whole. 



Especially striking is the similarity of the dark median area with 

 the same wing-part of ocellata; as in the latter it is cut up into a 

 fore- and a hind-quarter by funnel-shaped intrudings of the light- 

 brown ground colour, which may either meet each other or remain 

 separate. A single look at every somewhat considerable collection 



