A Parasite of the Bembex 



The hesitation of the Wasp hampered by 

 her load lasts but the twinkling of an eye. 

 No matter : this is long enough for the Gnat 

 to accomplish her misdeed without allow- 

 ing herself to be carried beyond the thresh- 

 old. How smoothly her organs must work 

 to adapt themselves to this instantaneous lay- 

 ing! The Bembex disappears, herself in- 

 troducing the enemy to the home; and the 

 Tachina goes and squats in the sun, close 

 to the burrow, to meditate fresh deeds of 

 darkness. If we wish to make sure that the 

 Fly's eggs have really been laid during this 

 rapid manoeuvre, we need only open the bur- 

 row and follow the Bembex to the bottom 

 of her dwelling. The prey which we take 

 from her bears at the tip of its abdomen at 

 least one egg, sometimes more, according to 

 the length of the delay at the entrance. 

 These eggs are too small to belong to any 

 but a parasite; besides, if any doubt re- 

 mained, separate rearing in a box results in 

 Fly-grubs, followed by the pupae and lastly 

 the Miltogrammse themselves. 



The moment adopted by the Gnat is chosen 

 with great discrimination : it is the only mo- 

 ment when she is able to accomplish her de- 

 signs without danger and without useless 

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