STUDIES ON THE BIOLOGY OF <i>RHYSSA PERSUASORIA</i> (L.) (HYMENOPTERA: ICHNEUMONIDAE) INCORPORATING AN X‐RAY TECHNIQUE

i Development of the immature stages of Rhyssa persuasoria (L.) on the larvae, prepupae and pupae of Sirex noctilio F. was followed in situ in Pinus radiata D. Don. by an X‐ray technique. R. persuasoria females were allowed to oviposit in wood in which the location of immature stages of S. noctilio had been determined radiographically. By this means it was found that they could not locate their hosts with certainty. When a host was located the female parasite paralysed it by stinging and laid an egg upon it. The host was consumed within five weeks and the parasite passed through four larval instars before pupation.