140 ENTOMOLOGICAL SOCIETY 



in the same place in both, the environment alone undergoing a 

 change. In this way the meaning of the color and shape be 

 comes particularly clear. 



Then illustrations proving the derivation of the colors of cer 

 tain caterpillars from the chlorophyll of their food-plant were 

 brought forward. The green or brown ground color of the 

 larva of Tryphcena pronuba was proved to depend upon the 

 chlorophyll of the leaves or upon the yellow etiolin, closely re 

 lated to chlorophyll. When, however, larvae were fed upon 

 the mid-ribs of the leaves, containing neither chlorophyll nor 

 etiolin in an available form, the power of producing such ground 

 color was wanting. 



Other illustrations showed some of the methods by which the 

 transparent spots and patches are formed on the wings of Lepi- 

 doptera in resemblance to holes in dead leaves, either by the loss 

 of scales, as in Kallima, or by reduction of the scales to hairs, as 

 in Attacus. 



Recent experiments upon the modification of the colors of 

 lepidopterous larva? by their colored surroundings were then 

 shown. These experiments have been conducted during the 

 past summer (1893). The larvae of Odontoptera bidentata 

 fed upon the same food-plant and, surrounded by twigs of vari 

 ous natural colors, possessed the power of resembling these lat 

 ter. When the twigs were covered with lichen, the larvae 

 possessed the power of developing green spots, resembling the 

 lichen. This part of the experiment was new, such suscepti 

 bility having never been previously proved to exist. The same 

 proved to be the case with Gastropacha quercifolia, in which 

 the lichen produced gray patches upon the larvae. In all these 

 larval color changes the result is due to the effect of light, not 

 food. 



As regards Warning Colors, two examples from Portchinski's 

 recent work were shown, the first proving that the attitude 

 assumed by the distasteful moths of the genus Spilosoma are 

 such as to display warning colors to enemies. The second ex 

 ample was the wonderful case of the pupa of Limenitis populi, 

 which is so marked and colored as to appear to have been 

 wounded. 



