358 REFLEX ACTIONS OF ARTICULATA. 



the vapour : if the same irritation be applied on the other 

 side, the reverse movement will take place; and the body 

 may be caused to bend in two or three curves, by bringing 

 the irritating vapour into the neighbourhood of different parts 

 of either side. This movement is evidently a reflex one, and 

 serves to withdraw the entrances of the air-tubes from the 

 source of irritation ; just as the act of sneezing in higher 

 animals causes the expulsion from the air-passages of any 

 irritating matter, whether solid, liquid, or gaseous, which may 

 have found its way into them; and we have no reason to 

 regard the former as more voluntary than the latter, which we 

 know to be purely reflex ( 342). 



444. Among Insects, we meet with reflex actions yet more 

 curious. The Mantis religiosa (fig. 187) is remarkable for the 



Fig. 187. MANTIS RELIGIOSA. 



peculiar conformation of its first pair of legs, which serve as 

 claws for seizing its prey ; and also for the peculiar attitude 

 which it assumes, especially when threatened or attacked. 

 Supporting itself upon its two hinder pairs of legs, it rears up 

 its head upon the long first segment of the thorax, elevating 

 at the same time its large and powerful arms ; and the resem- 

 blance fancied to exist between this attitude and that of prayer, 

 is the cause of the epithet religiosa having been given to it. 

 Now if the first segment 'of the thorax, with its attached 

 members, be removed, the posterior part of the body will 

 still remain balanced upon the four legs which belong to it ; 

 resisting any attempts to overthrow it, recovering its position 

 when disturbed, and performing the same agitated movements 

 of the wings as when the unmutilated animal is excited. But 

 it will remain quite at rest, so long as it is not irritated. On 

 the other hand, the detached portion of the thorax which 



