122 Object and Function of the Egg-stalk. 



certain buds were leaf-buds or flower-buds, and in most 

 cases my conjectures were correct. Sometimes even 

 after the fly has closely examined the bud with its 

 antennae, it may happen that the ovipositor, in piercing 

 it, affords different information, and immediately the 

 fly will leave that bud and seek another. The mere 

 fact that several galls occur only on the flowering 

 catkins, shows that the flies know how to distinguish the 

 flower-buds from others. 



In the descriptions of oviposition which I have already 

 given, it has been repeatedly shown that it is by means 

 of the egg-stalk being seized by the two spiculae and 

 pushed onwards, that the ^gg itself is drawn out. But 

 this cannot be the special function and intention of the 

 egg-stalk, as the following facts show. In the first place 

 it is very remarkable that stalked eggs occur only in 

 a small division of the hymenoptera ; and that they are 

 entirely wanting in the Pimplidae and Cryptidae, which 

 are mostly provided with very long ovipositors. We 

 are justified therefore in concluding that the stalk is 

 not absolutely necessary for the extrusion of the ^gg. 



The eggs of the Cynipidae are further distinguished 

 from the stalked eggs of other hymenoptera in this, that 

 in the former the egg-stalk is attached to the anterior, 

 in the latter to the posterior egg-pole ; consequently at 

 the birth of the egg in the first case, the real egg-body 

 takes the lead ; in the latter, the egg-stalk. This does 

 not agree well with the explanation given by Hartig, 

 who, neglecting the anatomical relations of the parts, 

 assumed that in the Cynipidae also, the egg-stalk was 

 born first. The egg contents according to this ought 



