LEFEBVRE ON MANTIS. 69 



same creatures had assumed that silvery tint which rendered 

 them undistinguishable from the asperities of the ground. 



Do they then live in these limited spheres without wander- 

 ing ? Can they, at pleasure, assume the colour of the soil on 

 which they may happen for a time to sojourn ? The physical 

 cause seems incapable of explanation. 



We well know that in the Polar regions several Mammi- 

 feroe, as well as birds, can (but only for a time) assume the 

 white colour of the snow ; but I do not think this chameleon 

 faculty has ever been observed among the Invertebrata. 



As for the intention of Nature in this case, must it not have 

 been to afford the Eremiaphila more facility to escape the 

 attacks of their enemies (since they are placed in a dangerous 

 position, being the only insects which in these regions can 

 serve as a prey) that she has identified these Orthoptera with 

 the colour of the soil so completely that it is totally impossible 

 to see them except when in motion. 



In spite of all my care, and all my investigations, I could 

 not find a single other insect in the habitats of the Eremiaphilcs. 

 Some, indeed, were to be seen in approaching the Oases, but 

 only in their immediate vicinity, and these were the genera 

 Anthia, Graphipterus, Scolia, Pimelia, Acrida, Mantis, 

 (proper,) Formica, the universal Vanessa cardui, the Da- 

 naides, &c, but when we came in sight of these the Eremi- 

 aphila had long disappeared ! 



This strange fact, which I had an opportunity of confirming 

 on my return from Bahryeh, by another route across the 

 desert, continued to puzzle my brains as much as before. 



What indeed can be the food of these Orthoptera 

 amidst such frightful wastes, where no other herbivorous 

 insect can by possibility exist ; for there is not a plant, not a 

 vestige of vegetation ; and where I met with them 1 never 

 found even the glasswort and colocynth, — sad and scanty 

 traces of vegetable life, but on which the eye dwells with plea- 

 sure^ and which are generally seen in parts more proximate to 

 habitable land. 



These Eremiaphilce , too, are armed with predatory claws, 

 strongly toothed, and are covered with elytra, hard and solid in 

 comparison with those of the other Mantides; every thing about 

 them announces habits essentially carnivorous— a life alone de- 



d See Note IV. 



