Abstract: The species-specific mutualism between figs and pollinating fig wasps is one of the hot topics in coevolution studies. Figs host a large number of non-pollinating fig wasps besides pollinators. Philotrypesis pilosa Mayr is characterized by the extreme extension of the last two tergites of abdomen, in the form of ovipositor sheath, followed by the true ovipositor sheath. It is a cleptopar asite of Ceratosolen solmsi, the legal pollinator of Ficus hispida L. The oviposition process of P. pilosa was recorded with a digital camera. We found the following behaviors which were ignored by the previous authors: 1) When the female finds out a suitable site for ovipositing, it makes a headstand posture, freeing the hind legs to help the long ovipositor sheath to locate the site. 2) From the start of penetrating the syconium to springing the ovipositor sheath backwards, the extension part of abdomen tergites and the ovipositor sheath undergo two bouts of close-and-apart. The first bout of close-and-apart is beneficial to keep the stylets vertical so as to penetrate the wall easily. The second one is helpful to spring the ovipositor sheath backwards and make the exposed basal part of the stylets to squeeze into the wall without the clag of the sheath. 3) The stylets penetrate into the syconium along syconial diameter as the shortest way. 4) The fore and hind legs are more robust than the mid ones, which is related to their function of supporting the body during the oviposition.

Key words: Philotrypesis pilosa, oviposition behavior, cleptoparasitism, morphological character evolution