ihr r(/(/-rafi(\<i ami early stagr^ of some Cassidid/v. P> 



does not move them duriDg the whole operation. The pos- 

 terior * pair of legs are held up so as to be out of the way. The 

 abdomen is then extended and the oothecal plates extruded. 

 Placing the tips of the plates against the surface of the 

 leaf she exudes a small quantity of colleterial fluid which 

 adheres to the leaf. Then compressing the oothecal plates 

 together and moving the abdomen upwards f this fluid is 

 drawn out between the plates as a thin membrane. Having 

 attained the limit of the upward movement, the two oothecal 

 plates are moved laterally upon one another, so that 

 the membrane is cut off. It rapidly dries and becomes 

 hard on exposure to the air, and is then tough and elastic. 

 To form a second membrane she brings the tip of the 

 abdomen again to the surface of the leaf, but a little on 

 one side of the point of attachment of the first membrane, 

 again exudes some colleterial fluid, and elevating the abdo- 

 men, another membrane is formed. Having thus fastened 

 a few membranes firmly to the leaf, the beetle now begins 

 to add the deposition of eggs to the process. 



An egg after passing down the oviduct becomes covered 

 with colleterial fluid. This egg is placed about the middle 

 of the membrane behind it (it is of course one previously 

 deposited : the formation of the ootheca proceeds from 

 behind forwards). The egg adhering in this position, the 

 abdomen is moved downwards (i. e. towards the leaf), but 

 when it has reached the limit of movement in this direction 

 it does not touch the leaf, but, moving in a parallel direc- 

 tion wilh that of the preceding membrane, is turned up- 

 wards so that the membrane is doubled, and the movement 

 continuing upwards the end of the membrane is left free 

 at the top, when the limit of upward movement is reached. 



A point of considerable interest may now be referred to. 

 It should be recollected that the ootheca is so formed that 

 when the eggs it contains have hatched the young have an 

 easy road for exit left at the top, but cannot escape at the 

 bottom of the ootheca. A similar condition exists as to 

 the egg-case of Mantida^, and has given rise to much diffi- 

 culty as to how it is brought about. The two authors of 

 this paper are not in agreement as to the mode in whicli 



* In other divisions of Chri/somelidae tlie hind -legs play a very 

 important part in the formation of the egg-envelope. 



f In this description of the process it is for the sake of clearness 

 supposed that the beetle is working right-side n-p on the upper- 

 sxirface of a leaf. Usually, Mr. Muir says, this is not the position. 



