191 9- Johnson. — Rhyssa persuasoria. 115 



RHYSSA PERSUASORIA IN THE COUNTIES OF 

 DOWN AND FERMANAGH. 



BY REV. W. F. JOHNSON, M.A., F.E.S., M.R.I. A. 



In June last I had a letter from Mr. C. M. Da vies of Lenaderg, 

 enclosing a large ichneumon fly which he had captured 

 flying about a rustic rose-arch. The insect was so much 

 crushed in the post that I could not satisfactorily determine 

 it, so I WTote to Mr. Da vies asking him to send me, if possible, 

 further specimens. This he most kindly did, sending me 

 two more. On examination these proved to be Rhyssa 

 persuasoria, Linn., a species for which I know of but two 

 records from Ireland, viz., Stradbally, Co. Waterford, by 

 Morley^ and Co. Louth by Pentland.- 



I was in Donegal when Mr. Davies wrote to me and 

 on my return I went to Lenaderg, where he and his brothers 

 most kindly showed me the rose-arch, and pointed out a 

 place which they had marked where Rhyssa had inserted 

 its terebra. I examined the place with a low power lens, 

 but as it was more than a month since Rhyssa had operated 

 naturally there was no trace of her boring, but it was plain 

 that it had been made into the solid wood. Mr. Davies 

 and his brothers watched Rhyssa at w^ork and have 

 communicated their observations to me. Rhyssa was 

 observed to run about on the wood trying one place after 

 another with its antennae as if prospecting for a suitable 

 place to make its attack. There were holes in the wood 

 made some by Sir ex gigas and others, which w^ere smaller, 

 by a Crabro of which Mr. Davies sent me specimens. Rhyssa 

 was seen to insert its ovipositor into these holes, having 

 first found them with its antennae ; but it was also seen 

 to bore into the solid wood at a place selected after careful 

 investigation with its antennae. In the ovipositor of 

 Rhyssa is comprised the terebra or borer and the valvulae 

 or sheaths, two in number, which enclose the terebra when 

 not being used for boring. Having selected a spot with 

 its antennae, the sheath being directed backwards, the 

 terebra is brought forward between the legs, and, guided 



^ *' British Ichneumons," iii., 28. ^ Irish Naturalist, xxi., 147-8. 



