The “nucleal reaction” in Apanteles sp., with special reference to the secondary nuclei and the germ-cell determinant of the egg

The question of the origin, nature and significance of the secondary nuclei and the 'germ-cell determinants, especially in the unfertilised eggs of the Hymenoptera, has been a subject of diverse opinion amongst the various observers. It is a curious fact that the secondary nuclei have not been found, except in Hemiptera, Lepidoptera, Coleoptera, Hymenoptera and Diptera, where they have been recorded by workers such as Blochmann (1), Stuhlmann (21), Korschelt (12), Paulcke (19), Marshall (18), Loyez (14), Hegner (8-11), Buchner (2) and Gatenby (6).