Forest entomology . iae and tarsi(fig. 175 a), and black colour of thehind legs. Head and thorax black,abdomen black and brown, antennaeas large as the body. Wingshyaline. Spread of wings 16mm. in male and 24 mm. infemale. The larvae (fig. 175 b) are bluish-green, with black head ; head, ex-treme end of abdomen, and prolegsquite yellow; one or two rows ofblack dots along the body. Lengtliabout 30 mm. The perfect saw - fly is a blackand light-red insect. In both sexeshead, thorax, and anal portion ofabdomen black ; remainder of abdomen light-brown. Wings hyaline ;stigma in female black, in male
Forest entomology . iae and tarsi(fig. 175 a), and black colour of thehind legs. Head and thorax black,abdomen black and brown, antennaeas large as the body. Wingshyaline. Spread of wings 16mm. in male and 24 mm. infemale. The larvae (fig. 175 b) are bluish-green, with black head ; head, ex-treme end of abdomen, and prolegsquite yellow; one or two rows ofblack dots along the body. Lengtliabout 30 mm. The perfect saw - fly is a blackand light-red insect. In both sexeshead, thorax, and anal portion ofabdomen black ; remainder of abdomen light-brown. Wings hyaline ;stigma in female black, in male light - brown. Length of male7 mm.; span of wings 16 mm.; female 11 mm.; span of wings24 mm. I have not worked out the life-history of this species, but Judeichand Nitsche say there is a double generation, the flies appearing inMay and August. It is very probable that this may be so in thesouth of England, while in the north of Scotland there maybe only one generation a-year. It is not very common Fig. 174.—Larva; of Croesus septen-trionalis on alder. 186 FOREST ENTOMOLOGY. Nematus (Holcocneme) Erichsonii, Htg. (the large Larch Saw-fly). This insect, though fairly common in some parts of this country, isnot even mentioned in any English literature relating to forest ento-mology. Cameron writes :1 Erichsonii does not appear to be a com-mon species. I have only seen a specimen taken by the Rev. T. , of which I did not know the locality. Mr Dale records itfrom Glanvilles Wootton. In German literature Judeich and Nitsche,2and also Niisslin,3 only slightly refer to this species. Packard4
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