22 THE BNTOIVIOLOGIST. 



had already taken its departure, they are necessarily crude, as 

 it was the only example of its kind on which I had ever set eyes. 

 For this and for their obvious artistic defects I shall make no 

 further apology, as they are merely intended to convey the 

 manner in which the insect accomplished its object. 



Sharp* figures (after Eiley) the allied genus Thalessa in the 

 act of oviposition, and states that in both these genera the 

 ovipositor " is brought into use by being bent on itself over the 

 back of the insect, so as to bring the tip vertically down on to 

 the wood, through which it is then forced by a series of efforts ; 

 the sheaths do not enter the wood." 



It is evident that this description does not tally with the 

 foregoing observations on Rhyssa. The insect figured by Sharp 

 follows his statements in having its long ovipositor bent on itself, 

 out of its normal and approximately straight form, into an almost 

 complete circle. From purely physical considerations, is it not 

 a little difiicult to understand how a non-muscular structure 

 could be curved at will in this way ? The possibility suggests 

 itself to the present writer that the insect there figured, after 

 having inserted its ovipositor in the manner described in this 

 note for Rhyssa, may have pivoted its body through an angle of 

 180° around the flexible fixed ovipositor, in its efforts to thrust 

 the latter into an unusually resistant piece of wood. This might 

 easily happen through the insect's shifting its feet again and 

 again to obtain a better purchase, and would explain the whole 

 matter very simply, as the ovipositor in such a case would 

 naturally assume the position figured. 



[There can be no doubt at all that Mr. Ramsay's notes refer 

 to R. persiiasoria, L., which has an extremely wide distribution 

 through Europe to Canada and the United States in the West, 

 and the Himalayas in the East, since it is to the best of my 

 knowledge the only species attacking pinetophagous larvae. R. 

 approximator, Fab., is said by Holmgren to attack Xyphydria 

 prolongata, which feeds in oak ; and there are several interesting 

 accounts of the American species' economy (Canad. Entom. xi. 

 1879, p. 15, &c.) and Harrington has {I. c. xix. p. 206) put on 

 record " The Nuptials of Thalessa.'' Mr. Ramsay appears to 

 take it for granted that these insects bore for themselves an egg- 

 passage through the solid wood ; but it is by no means proved 

 that they do not oftener introduce them along the tunnel of the 

 host larva {cf. Mori. Ichn. Brit. iii. p. 25, et Revision Ichn. Brit. 

 Mus. ii. p. 10). — Claude Morley.] 



■t= ' Cambridge Natural History, lasects,' pt. i. p. 554, 1895. 



