8 BULLETIN 730, U. S, DEPARTMENT OF AGRICULTURE. 



EGGS AND OPPOSITION. 



The eggs are placed singly in cavities eaten out of the fruit, the 

 cavities averaging slightly more than 1 mm. deep by 2 mm. wide. 

 (PL I, E, F) The wound is relatively large, and, even in cases 

 where the eggs do not hatch, the hardening of the tissues about the 

 cavity, which take place during the healing process, ruins the fruit 

 for all purposes except that of juice extraction. 



In ovipositing the female selects with some care a point, which 

 may be at any place on the surface of the grape, and makes a small 

 opening through the skin with her snout. Without changing her 

 position on the grape she then excavates through the small opening 

 all the pulp within convenient reach of the snout, the completed 

 cavity extending back beneath the body of the beetle. (PL I, A) 

 All the pulp removed is swallowed, and excrement is voided in small 

 quantities during the operation. When the cavity is finished the 

 beetle turns around, as though on a pivot, and places the tip of the 

 abdomen over the opening in the skin. (PL I, C) On several 

 occasions as the beetle was in the act of turning, a section of the 

 grape was cut away by the observer so as to expose the lower end of 

 the egg chamber, thus permitting oviposition to be watched from 

 within through a hand lens. This showed, immediately following 

 the appearance of the tip of the abdomen at the opening, a slender 

 ovipositor extended and moved about touching the sides of the 

 chamber. The ovipositor was then withdrawn into the body, but a 

 few seconds later it was suddenly extruded to its full length and 

 pointed rigidly forward, and at this time the movement of the egg 

 could be seen passing down the duct. The tip of the abdomen at 

 the moment was in contact with the wall of the chamber at the point 

 farthest from the opening in the skin, and the egg was ejected and 

 attached at this point (PL I, E), after which the ovipositor was 

 slowly withdrawn into the body. 



After the egg is deposited the beetle ejects a mass of excrement 

 over the opening in the skin (PL I, D), presses some of the more 

 solid matter of the excrement into the opening with the tip of the 

 abdomen, and then moves away. This excrement soon dries and 

 seals the cavity (PL I, G). Frequently the female is attended by a 

 male during the preparation of the egg chamber and the work is 

 interrupted by copulation. Table II shows how the time was 

 observed to be divided in six instances where the duration of the 

 different steps was recorded. 



