On a New Schizogregarine:Schizocystis legerin. sp, an Intestinal Parasite of Dipterous Larvae (Systenus)

Abstract

The hosts of the new Schizogregarine herein described are the larvae of Dolichopodid flies:Syslenus adpropinquansLoew andS. scholtziiLoew which live in the decomposed sap or wood-pulp filling the wounds of Elm and Horsechestnut trees. The larvae used for the present study have been obtained from two trees only: an Elm tree standing on the Caius College playing ground at Newnham and a Horse-chestnut tree standing on the Downing site. The new parasiteSchizocystis legerin.sp., in company with a gregarineDendrorhynchus systeniKeilin (1920), often completely fills the lumen of the host's midgut, but, even when heavily parasitised, the host does not show any sign of infection. The latter can only be detected when the larvae, slightly pressed between a slide and a coverslip, are examined under the microscope.