142 



ENTOMOLOGICAL SOCIETY 



APRIL 5, 1894. 



President Ashmead in the chair, and Messrs. Benton, Chitten- 

 den, Gill, Linell, Coquillett, Schwarz, De Schweinitz, and 

 Heidemann were also present. 



The following paper was read by the Corresponding Secretary 

 in the absence of the author : 



FURTHER NOTE ON THE STRUCTURE OF THE OVIPOSITOR 

 IN HYMENOPTERA. 



By C. L. MARL ATT. 



Having recently, through the kindness of Mr. Howard, ob 

 tained a living specimen of Pimpla conquisitor Say, I under 

 took to settle a point in the structure of the ovipositor, as out 

 lined in previous communications before the Society*, which I 

 had not established to my own satisfaction, owing to the impos 

 sibility of determining the relation of the parts from dried museum 

 specimens. In examining the living insect the motions of the 

 parts could be witnessed under a hand-glass, and the structure 

 and joints, which before could only be surmised, definitely differ 

 entiated. The point in doubt in the previous 

 studies was the manner of union of the inner 

 branches of the spicula (see <?, # , and $, Fig 

 ure 8). As previously described by me, each 

 spiculum sends off an inner branch near the 

 base, and these branches I had previously sup 

 posed united in forming a loop of uniform 

 size throughout. In the r case of Pimpla, at 

 least, in the living specimen, it was seen that 

 these branches, instead of being united in one 

 piece, are connected by a sort of subsidiary 

 cross-piece, or oscillating lever, b, in the ends 

 of which they are joined in a sort of ball- 

 and-socket joint, so that with the alternate motion up and 

 down of the spicula during the action of the ovipositor, either in 

 attempting to sting or in oviposition, the ends of what may be 

 called the spicule-cross-bar move alternately up and down in a 

 manner similar to the motion of a steamboat's walking-beam, 

 except that the central support of the walking-beam is lacking. 

 The hyaline integument, w r hich forms the outer covering of the 



* i. Notes on the Genus Metopius, etc., Proc. Ent. Soc. Wash., vol. ii, 

 p. 101. 



2. A study of the Ovipositor of Hymenoptera, 1. c., p. 201. 



FIG. 8. Bases of spicula 

 of ovipositor of Pimpla 

 conquisitor (original). 



