STUDI SUGLI IMENOTTERI ICNEUMONIDI IV.

Abstract

The A. begins with rhis note the srudy of the genus Phygadeuon Grav. s.I.; after a generai look at the group, he examines the species which C.G. THOMSON described as belonging to this genus.

The biological data are incomplete, fragmentary and sometimes contradictory. However it is possible to state from them that many species are ectoparasites of larvae and pupae of Diptera Anthomyiidae, Larvaevoridae, and Trypetidae and that other species described by AA. as Phygadeuon are today assigned to less vast genera whose species bave a uniform biology.

The genus groups species living in the northern hemisphere. From the observations of various AA and personal ones the tendency of these Terebranlia to live on low vegetation and even in the anfractuosities of the ground is noticed: this should be related to the fact that secondary hosts (Dermaplera, Noctuidae, Tipulidae, Popillia iaponica) live in the ground and that primary hosts (especially Diptera Anthomyiidae) frequently live on low vegetation or let fall themselves to the ground just before pupating (Antho- myiidae and Trypetidae).

The A. puts in evidence the variabiliry of morphological characters after having examined large series of Phygadeuon trichops Thoms. and Ph. wiesmanni Sachtl. reared from known hosts. For example, in the former species, the clipeal teeth of female and the abdominal tergites IDJcrosculpture of male are not stable characters.

The A. revises the rypes of 51 species which TIIOMSON included in the genus Phygadeuon. The designations of lecrorypes (17 species), neotypes (l species) and the following seven new combinations are here publisbed: Theroscopus annulicornis (Thoms.), Medophron caudatus (Thoms.) (recte caudatulus D.T.), Theroscopus facialis (Thoms.) (recte faciator Aubert), Medophron flavipes (recte flavitarsis D.T.), Dichrogaster heteropus (Thoms.), Theroscopus ochrogaster (Thoms.) and Medophron recurvus (Thoms.).