Rau — The Biology of Stagmomantis Carolina. 27 



shading into brown at the exposed parts, while the 

 ventral and lateral parts, as well as legs, head and 

 thorax,— in fact all constantly exposed parts — were dark 

 brown. 



On another occasion several green females in the next 

 to the last instar were placed in a breeding cage together 

 with several pots of growing grass which would serve 

 as a background and foothold for both the mantis and 

 their prey. During a heavy shower the cages were taken 

 into an outbuilding, and fortunately or unfortunately 

 they were forgotten there for about a week. During 

 this time the grass died and turned straw. When they 

 were discovered the mantis had devoured one another, 

 but the two survivors which were found with difficulty 

 had become adult, and there they were — body, legs, wings 

 and all just the right shade of straw color. 



This led to other work with the insects. The difficulty 

 of maintaining in one's own home a large number of 

 animals which are cannibalistic, voracious and carnivor- 

 ous, and which require a variety of living food can 

 perhaps be imagined. 



In an experimental way I tried to find just how and 

 why the colors changed and if environmental conditions 

 were the sole causal factor. For three years the work 

 was carried on with not at all encouraging results. The 

 first year lamp-chimney breeders were used. The mor- 

 tality was great owing to the difficulty in the regulation 

 of moisture and temperature. The second year a number 

 of home-made wire cages were used and a large number 

 of individuals placed in each. The extreme cannibalistic 

 tendencies reduced the numbers to almost nothing, but 

 the work still gave a clue to what were the tendencies of 

 the adaptation of the animal to its environment. Later 

 about a hundred fly-traps were procured and set up as 

 described elsewhere in these pages. 



The work will probably be carried on for another 

 season, but enough data have been gathered that we can 



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