28 Trans. Acad. Sci. of St. Louis. 



coniidently state in a preliminary way at least these 

 conclusions ; 



1. The green nymx)hs are capable of changing to dark 

 gray or brown when the environment is dark. 



2. The green insects will in all probability remain 

 green when the environment is favorable to that color. 



3. When once the gray color is acquired it is perma- 

 nent despite any environmental conditions. 



Poulton^^ says that "all green colouration without 

 exception is due to chlorophyll, while nearly all yellows 

 are due to xanthophyil. " Tower in his work on Colors 

 and Color Patterns in Coleoptera goes more into detail 

 on the coloration of Orthoptera. He says that in the 

 Orthoptera the prevailing colors are blacks, browns, 

 greens, yellows and rarely reds; the browns, blacks and 

 some of the yellows are cuticular colors; the reds and 

 most of the yellows are hypodermal. The Orthopteran 

 forms are largely vegetable feeders and ''the greens and 

 yellows are centainly in part derived from plant pig- 

 ments." Thus the two color authorities reach the same 

 conclusion, that the greens and yellows are derived from 

 plant pigments. But here a mantis, an Orthopteran 

 form which never in its life eats anything but animal 

 food, attains precisely those colors. It is true that this 

 insect, while entirely carnivorous, might acquire a cer- 

 tain amount of chlorophyll by feeding upon insects 

 which in turn are phytophagous (caterpillars, aphis, 

 etc.) and thus develop the green color, but in that event 

 why should this effect follow in only a part of the insects 

 when all of them live upon practically the same food 

 supply? 



To assume that the coloration of the mantis is a 

 vestige from the time w^hen their ancestors were vege- 

 table feeders is far from satisfying. 



" Quoted by Vernon, Variation in Animals and Plants, p. 291. 



