OF WASHINGTON. 257 



While appearing like a single piece, it is in reality double or com 

 posed of two parts which, indeed, are separated at the extreme 

 base, but otherwise firmly soldered together. The spiculaB are 

 serrate or notched at the tip, and the seta often ends in a slight 

 hook. The two spiculae play, by means of strong basal muscles, 

 longitudinally up and down, by means of the grooves which em 

 brace the tenons of the seta. 



The eggs of Cynipidas are characterized by having a stalk 

 or pedicel of varying length according to the species, the egg- 

 body pr6per, according to Adler, being at the apical or anterior 

 end which first issues from the body, and the basal or posterior 

 end being also somewhat enlarged or spatulate. In repose, the 

 ovipositor is concealed within two sheaths, but in oviposition, ac 

 cording to Hartig's views, the spiculae grasp the egg-stalk and 

 push it to the tip, the fluids being pressed back in the operation, 

 so that they come to be distributed along the stalk or to lie at the 

 opposite or posterior pole of the stalk. The spiculae then slightly 

 separate at the tip from the seta and extend beyond it so that the 

 apical end of the stalk becomes free. Now, by pressure, the 

 fluid at the posterior end passes through the stalk into the oppo 

 site or apical end which is plunged in the plant, the basal por 

 tion becoming emptied, the swollen apical end thus remaining in 

 the plant when the ovipositor is withdrawn, filling the distal 

 end of the puncture, which is somewhat enlarged. The empty 

 basal sack of the egg and a portion of the stalk are often left ex 

 posed, looking not unlike the empty egg of some lace- wing fly 

 (Hemerobiid] . In short, Hartig's view, very generally adopted, 

 was that the extensile and ductile egg was driven through the ovi 

 positor itself while this was in the plant, and that the contents of 

 the egg-body wei'e pressed back into the egg-stalk or pedicel dur 

 ing the operation and collected in the posterior end, and only 

 after the apical end had reached the bottom of the puncture did 

 these contents stream back into it. 



Adler would refute this view, and draws attention to his own 

 figures on Plate 3, where the eggs and ovipositor are illustrated 

 side by side, all taken from photographs and drawn from the 

 same amplification. These show that the ovipositor is, in every 

 case, longer than the egg itself, the enlarged head of the egg cor 

 responding in direction to the tip of the ovipositor. He argues 

 from this fact that one end of the egg cannot be in the plant tis 

 sue while the other is in the canal. He further argues that it is 

 not possible that the whole egg can be received into the ovipositor 

 and glide through it in the way in which Hartig supposed. Let 

 me give in his own words the description of the process which 

 he has followed, particularly on Neuroterus Iceviuscuhis (the 

 agamic vernal form of Spathegaster albipes), while ovipositing 

 in an oak bud. 



