367 



knobs, in the same fashion as the vein-traces, without, however, 

 showing the longitudinal division. On close inspection a trans- 

 verse series of light knobs may be distinguished in the same 

 situation as the outer of the two rows of Goncptcryx rhauDii, 

 to which E. carda))iincs stands nearest, both in pupal form and 

 in ornamentation of the wing-sheath. Accordingly, in this 

 species also, a black patch, standing out in high relief, brings 

 into prominence the corner of the discoidal cell. 



From the comparison of the pupai of the representatives of 

 these different families, Nyniphalidcr, Papilionidœ, and Picridw, 

 I consider myself justified in drawing the following general con- 

 clusion : the wing-sheaths of these butterflies show a common 

 ground- plan of ornamentation, consisting of dark pigment, 

 accumulated partly along the pupal wing-veins and partlv in 

 the middle stripe of the wing-cell. Besides this distribution of 

 coloured matter, two transverse series of interveinal knobs or 

 spots of a lighter hue are found : one row along the outer margin 

 of the imaginai wing-field, the other half-way between this margin 

 and the transverse discoidal vein. These knobs or spots are 

 found in different stages of retrogression up to total disappearance. 



The Development of the Primitive Pattern. 



I. Vanessa urticœ. 



The development of the primitive or interpupal pattern 

 begins very early, in the first days after pupation. At that 

 period the wing-rudiments are in an embryonic or undifferentiated 

 condition, the mother-cells of the scales still possess the character 

 of simple epidermic cells, and the tracheal veins show the original 

 arrangement (first discovered by Fritz Müller), without dis- 

 coidal cell-vein. The future colouring material is found in the 

 mother-cells of the scales in the form of uncolourcd pigment- 

 grains, which on exposure to atmospheric air assume a red tint 

 in the course of a few hours. Fixation in cohol prevents this 

 discoloration. Under normal conditions the wings are at the 

 beginning fairly transparent, the pigment-grains do not as yet 

 show a tint, and the light passes freely through them. Hut 

 soon a difference between llic antero-exterior and the postero- 



