OF ARTS A^^D SCIENCES. 253 



possesses an orange tubercle, surrounded with black, where the first 

 stage had a tailed appendage. The third stage is either similar to 

 Pterogon oenotherce, dark gray with numerous irregular and very- 

 fine jmler lines and some darker longitudinal ones, or is black, with 

 large transversal bright yellow bands (indeed so large that the color 

 can also be described as yellow with transversal and longitudinal 

 black bands), and both have instead of a tailed appendage a promi- 

 nently black and large eye-spot. The dififerently colored caterpillars 

 represent not the two sexes, as I have raised males which are entirely 

 alike in color and pattern, from both forms of the caterpillar. Both 

 forms live on the same vine (Ampelopsis qm'nqiiefolia), but the 

 yellow ones are rare. All stages live and feed during the daytime on 

 the vine, the very visible pink ones and the yellow ones, which would 

 need some protection, and the gray ones, which do not need it. I 

 remark purposely that the latter does not go in the daytime on dry 

 stems, as Weismann (p. 80) records for Pterogon oenotherce^ but feeds 

 on the green leaves together with the other ones. 



The question why this pattern, when considered to be the consequence 

 of the before-q.uoted causes, is not developed in every caterpillar, is 

 still to be answered. A large number of conclusions of a similar 

 character accepted now-a-days are based on exceptions, if we consider 

 the large number of species which do not agree with them. So feed 

 in North America the very large caterpillars of Chserocampa openly, 

 during daytime, contrary to Weismann's statement for the European 

 species. Exactly in the same manner feed openly in daytime a 

 number of uniform light green caterpillars, which must nevertheless 

 be well protected, as they belong to common species. That the varie- 

 gated colored ones are repugnant to a higher degree than the not 

 variegated ones, is still to be proved. Both are rarely taken here by 

 birds, as far as 1 know. That such caterpillars live upon poisonous 

 plants is true for some European species (Slater, Trans. Entom. Soc. 

 London, 1877, p. 205). I believe Weismann's statements are only 

 to be admitted as true ones as far as they go, but not in a general 

 way. 



I may state that at least one case is known to me where a 

 difference in feeding caterpillars exaggerated the pattern. An ento- 

 mologist in Prussia a few years ago divided a large lot of Sphinx 

 caterpillars of the same species, and fed both with tLe same leaves. 

 The stalks of one lot had been placed in fresh water, and of the other 

 lot in salt water. Both grew very well, but the latter differed con- 



