In the years 1988/89,222 egg-batches of the pine processionary caterpillar Thaumetopoea pityocampa (Den. & Schiff.) collected in Greece were studied in the laboratory for one year. Data on structure and size of the batches as well as a method rendering quite accurate estimates of the number of eggs per batch are presented. Altogether 10 871 parasitoids belonging to 6 species of Chalcidoidea emerged from the samples. The three most abundant species were Eutetrastichus servadeii (Dom.), Ooencyrtus pityocampae Mercet and Eutetrastichus sp. near servadeii. In the samples collected on Kassandra (KI) and on the Peloponnes (P) in autumn 1988 shortly after oviposition, the number of emer ing primary arasitoids was largely related to the duration of field exposure of the batches. Caterpiflars hatched from 67 YO of the eg s of these sample units. In egg-batches collected on Kassandra after 7 months of exposure in the f i e d (KII) a much greater parasitoid impact was observed. Not only did they yield more adult parasitoids throughout the first year; a striking difference was the much higher proportion of eggs without hatching or emergence holes, a majority of which showed signs of parasitoid attack.Only 4 % of the eggs appeared to be sterile after one year. Host mortality in the KII egg-batches was calculated to be 63 %.

In four regions of the Iberian Peninsula 162 egg!batches of the pine processionary moth were collected after hatching of the caterpillars in 0880 and 0881[ After collection\ the batches were stored singly in test tubes closed with foam stoppers under laboratory conditions at 19Ð14>C[ The number of eggs in each egg!batch varied between 26 and 201 and the length of the batches between 9[5 and 3[1 cm[ Independently of the pine species infested\ seven to nine rows of eggs were counted\ wrapped around one pair of needles[ A correlation was found between number of eggs and the product of number of egg rows and length of egg!batches "71) ³ r 1 ³ 86)#[ Oviposition almost always started from the base towards the tip of the needles[ The egg parasitoids that emerged were counted daily\ removed and identi_ed[ Later in the year of oviposition\ after the end of the period of emergence of the parasitoids\ the scale cover of the egg! batches were removed[ One year later\ all eggs were opened and the contents\ such as parasitoid meconia and remains of caterpillars\ were determined[ The hatching rate of the caterpillars varied from 36[1 to 68[6)[ The rate of parasitism uctuated between 00[2 and 20[6)\ but 33) of parasitoids died before successful emergence[ Four species of Chal! cidoidea were identi_ed] Baryscapus servadeii "Dom[#\ Ooencyrtus pityocampae "Mercet#\ Anastatus bifasciatus "Fonsc[# and Trichogramma sp[ Baryscapus servadeii and O[ pityocampae were the most abundant species\ followed by Trich! ogramma sp[ Baryscapus servadeii emerged mainly in June and O[ pityocampae in April or June\ depending on the region[ For A[ bifasciatus only males\ and for B[ servadeii females emerged except one male[ In O[ pityocampae\ a relatively high percentage of males "4[3Ð09[3)# was found[