436 



Journal of Agricultural Research 



Vol. XV, No. 8 



this blade, through which the toxin flows during oviposition. A slight 

 temporary paralysis of the larva seems to result after the ovipositor is 

 fairly inserted, for little struggling ensues after the oigg is extruded. 

 The two other parts of the ovipositor, in addition to the piercing blades, 

 consist of the outer pair of hollow sheaths (fig. i8, a, e), which do not pene- 

 trate beyond the surface of the fruit during oviposition unless the larva 

 attacked lies under a large break or hole in the fruit. Several hours after 



A BCD £ 



Fig. i8. — Diachasma tryoni: Parts of ovipositor: A, E, lateral sheaths; B, poison blade; C and D, piercing 

 blades, showing characters of ends of each blade. Greatly enlarged. 



a larva has been stung, a minute, oval, brownish spot develops on its 

 body at the point where the ovipositor was inserted. This spot becomes 

 a permanent scar and can be distinctly seen on the surface of the pupa- 

 rium. The female exhibits no decided capacity for discerning parasitized 

 from unparasitized larvae. Superparasitism is thus very common, al- 

 though only one parasite ever develops in a superparasitized larva. This 

 is owing to the cannibalistic habits of newly hatched larvae of Diachasma 

 tryoni. 



