BEETLES 177 



elevating the abdomen, 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 direction with that of the preceding mem- 

 brane, is turned upwards 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. . . . The egg 

 and membrane having been thus deposited, another 

 egg is placed by the side of the first (and of course 

 on the anterior face of the membrane), and the process 

 is repeated. The series of four rows of eggs is attained 

 by means of slight lateral movement of the abdomen. 

 . . . The membranes are soft and pliable when ex- 

 truded from the oothecal cavity, and rapidly become 

 solid, and thus retain the form they are made to 

 assume during the construction. The cells are made 

 to a large extent by the eggs pushing apart the mem- 

 branes in some places, and pushing them together in 

 others, but they are partly due to the shape of the 

 membranes, which are, each one, curvate, and more- 

 over are doubled so that sometimes two concave 

 faces are brought together; in other cases the outside 

 edge of a membrane projects somewhat, and thus 



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