Studies on Symphyta

Abstract

This paper deals with the observations on the life-history and biology of two Pamphilid-sawflies, Pamphilius volatilis (SMITH, 1874) and Neurotoma iridescens (ANDRE, 1882), pests of cherry-trees in Japan. The observations were made mainly in 1955•1956 in Sasayama district of Hyogo Prefecture and the data are summarized as follows: Pamphilius volatilis The adults appear during the period from the middle of April to the beginning of May. The male lives for a week and the female three weeks. The egg period takes about 11 days, the larval period about 22 days, the prepupal period about 10 months and the pupal period about 17 days. The female lays her eggs in a group, consisted of about 8 eggs, between 2nd and 4th interveinal parts of the underside of a leaf about 2 meters above the ground. The larva has 4 moults in both sexes. A group of hatched larvae cooperate with themselves in making a large leaf roll on the leaf-edge by means of their threads, but growing mature they divide into 2 or 3 groups on different leaves. The full grown larva, as soon as it stops to lay threads, falls down to the ground and burrows to considerable depth, about 30 cm, where it makes its pupal chamber. Two species of cherry-trees, Prunus yedoensis Mats. and P. Jamasakura Sieb., are recognized as the food plants, judging from the host-selecting experiments on both adults and larvae. No parasite could be found, bur 5 species of the spiders belonging to the genera Clubiona, Misumena and Argiop, were observed attacking the larvae. © 1958, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.