MAYER: COLOR AND COLOR-PATTERNS. 191 



able to withstand the most severe cold while in hibernation during 

 the winter, it is of great importance for them to absorb as much heat 

 as possible during the short summer. He placed several species of 

 lepidopterous larvae upon a snow surface exposed to bright sunshine. 

 The snow melted at different rates under the various larvae, and 

 in two hours the darkest insect had sunk b}' far the deepest into the 

 snow, proving that it was the best absorber of heat. This ingeni- 

 ous experiment of Lord Walsingham should be made the beginning 

 of an extensive and careful research. 



Chapman ('88) has shown that it may be of advantage to moths 

 inhabiting wet regions to display dark colors, or become melanic. 

 His observations were made upon Diamea flagella, and he says that 

 upon one showery afternoon he observed that one side of the tree 

 trunks was wet and dark in color ; the other side being dry was 

 paler. "As a consequence, the dark specimens of flagella were very 

 conspicuous upon the dry poi'tions, hardly visible on the wet, whilst 

 with the ordinary form the conditions were reversed, those on the 

 wet bark were conspicuous, those on the dry much less so." Per- 

 haps the dull coloration of Arctic moths may be partially due to the 

 effect of the somber background of rocks in the regions which they 

 inhabit. 



(6) Relation between Climate and Colors of Paj)ilios. It is well 

 known that the Lepidoptera in the Tropics display the richest 

 variety and greatest number of colors. I have counted the colors 

 exhibited by the 2*2 species of Papilio enumerated by Edwards as 

 inhabiting Xorth America north of Mexico, and also those which 

 are displayed by the 200 species of Papilio named in Schatz's list as 

 found in South America. The " colors " were determined by com- 

 parison with the colored plates in Ridgway ('86). 



In this manner it was determined that the Xorth American 

 Papilios exhibit 17 colors, viz., black, brown, primrose-yellow, canary- 

 yellow, sulphur-yellow, orange, white, greenish white, apple-green, 

 cream-color, azure-blue, sage-green, rufous, pearl-gray, indigo-blue, 

 iridescent blue, n-idescent green. 



On the other hand the South .\merican Papilios exhibited 36 

 colors, viz., black, translucent black, brown, white, canarj^-yellow, 

 citron-yellow, olive-yellow, primrose-yellow, chrome-yellow, straw- 

 yellow, gamboge-yellow, cream-color, greenish white, apple-green, 

 malachite-green, emerald-green, sage-green, slaty green iridescence, 

 pea-green, azure-blue, iridescent Berlin-blue, indigo, pearl-blue, 



