ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 203 



taken a step forward in understanding the origin of tlie pattern. The 

 author knows very well that among the Odonata patterns exist which 

 do not agree with the explanation, and in one case are even opposed 

 to it. But though most of the patterns can be explained in this 

 manner, there may exist other factors still unknown explaining the 

 opposite patterns. The explanation given can be considered as 

 admissible as long as the number opposite to it is a comparatively 

 small one. The pattern on the wings and elytra cannot, of course, be 

 the product of action near or along the muscles, as these limbs are 

 unprovided with them internally. But it seems probable that there 

 the sudden rush of blood and air by the accelerated circulation and 

 respiration during the act of transformation produces the same effect. 

 At least some patterns, the origin of which would be inexplicable, 

 would be understood by it. 



If a stream or jet of blood passing through the narrow base of the 

 wingbag should meet within its centre a small obstacle, the previously 

 straight stream would take the form of a funnel. Should this obstacle 

 be a kind of ring, the funnel shape would be retained by the stream, 

 but its central portion would pass undivided through the ring, and 

 upon meeting another obstacle would produce a second funnel. 

 Therefore there may be two or more funnels, one within the other, 

 and a section of them will be circular or elliptical according to the 

 angle to which they reach the inner surface of the wing. A curious 

 fact seems, the author thinks, to support his suggestion. Nearly every 

 larger ring or eye-spot of the wings shows a white interruption or 

 spot in some place. Now as it is impossible that any obstacle, such as 

 mentioned before, can be entirely free and isolated in the stream, we 

 must presume that it is somewhere connected with the interior of the 

 body, and is perhaps produced by some prominent ridge or corner, 

 and then the funnel or the ring must be interrupted in some place by 

 this connection. If it is so, this place will not be oxidated (colourless) 

 and will correspond to the white spot mentioned before. 



There is still another circumstance which explains some patterns. 

 The walls of the bag which will be later a wing or elytron are very 

 strongly enlarged and suddenly dilated during the act of transforma- 

 tion. Therefore small rudimentary patterns in the bag will be altered 

 and enlarged by the same proceedings. Many patterns of Lepidop- 

 terous wings can be easily explained in this way. All the wavy lines 

 and similar marks belong to these patterns. As the ribs or veins of 

 the wings seem to grow faster in transformation than the membrane 

 between them, the wavy shape of the lines would thus be explained. 



The author adds "At first my suggestion about the formation of 

 the pattern in such a manner may seem to be strange, and perhaps 

 not admissible. But in thinking over the subject again and again, I 

 have found more and more support for its adoption." He further 

 refers to the authority of Prof. C. Semper in proof of the existence of 

 obstacles in the streams of blood, and to the dark coloration round 

 the nipple of pregnant women as a proof of the appearance of dark 

 colour along an accelerated circulation. 



The colours of the patterns are dermal colours. They may, and 

 in fact do, often cover the whole insect. All colours, the pattern 



