206 
Psyche 
[September 
fewer lines of defense than the adults. In P. spinulosus there are 
no obvious differences between the ecology of the adult females and 
the nymphs which suggest that there could be any great difference in 
susceptibility to predation. The size difference between the last 
nymphal stage and the adults is not striking. It is my general im- 
pression that in tropical forests, individual phasmids (of any one spe- 
cies) may be highly dispersed and adult males may, as a consequence, 
have to search actively over considerable distances for females. Such 
searching could presumably render males more liable to predation 
than nymphs or females and might favor the evolution of more lines 
of defense in this sex. This seems to be true of the wingless phasmid 
Oncotophasma martini (Griffini) (Robinson, in press b ). In the 
case of P. spinulosus , males have been caught flying to light at dis- 
tances of several hundred meters from the nearest food plant. Their 
retention of the power of flight may provide them with an efficient 
means of escape not available to the females. 
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