THE MANTIS.— THE NEST 91 



of temperature. She emits a glutinous substance like 

 the Hquid secretion of silk-worms, and with this 

 composition, mixed instantaneously with the outer air, 

 she produces the foam of which the nest is constructed. 



She whips the secretion as we whip white of egg, 

 in order to make it rise and stiffen. The extremity of 

 the abdomen opens in a long cleft, forming two lateral 

 ladles which open and shut with a rapid, incessant 

 movement, beating the viscous liquid and converting it 

 into foam as it is secreted. Beside the two oscillating 

 ladles we see the internal organs rising and falling, 

 protruding and retreating like a piston-rod, but it is 

 impossible to observe the precise nature of their action, 

 bathed as they are in the opaque blob of foam. 



The end of the abdomen, continually palpitating, 

 rapidly closing and opening its valves, oscillates right 

 and left like a pendulum. From each of these oscilla- 

 tions results a layer of eggs in the interior, and a 

 transversal crevice on the exterior. As it advances in 

 the arc described, suddenly, and at frequent intervals, 

 it plunges deeper into the foam, as though burying 

 something at the bottom of the frothy mass. Each time 

 it does so an egg is doubtless deposited ; but the 

 operation is so rapid, and takes place under conditions 

 so unfavourable for observation, that I have never once 

 been enabled to see the oviduct at work. I can only 

 judge of the advent of the eggs by the movements of the 

 end of the abdomen, which is immersed more deeply 

 with a sudden plunging movement. 



At the same time the viscous composition is emitted 

 in intermittent waves, and is beaten into a foam by the 

 terminal valves. The foam thus obtained spreads itself 



