Forest entomology . dI therefore ignore them. The shaded space indicates a very deepimpression between the meso- and meta-thoracic may add that— the pro-thorax includes the areas a and Jc ; the meso-thorax includes the areas c, d, and e in fig 157; n and Iin fig. 158 ; HYMENOPTERA—SAW-FLIES, ETC. 167 the meta-thorax includes the areas/in fig. 157, oand m in fig. 158; the propodeum (g in both figures) is an originally abdominal seg-ment, transferred to the thorax in pupation. The thorax of a saw-fly can easily be broken up into its threeconstituent parts of pro-, meso-, and meta-thora
Forest entomology . dI therefore ignore them. The shaded space indicates a very deepimpression between the meso- and meta-thoracic may add that— the pro-thorax includes the areas a and Jc ; the meso-thorax includes the areas c, d, and e in fig 157; n and Iin fig. 158 ; HYMENOPTERA—SAW-FLIES, ETC. 167 the meta-thorax includes the areas/in fig. 157, oand m in fig. 158; the propodeum (g in both figures) is an originally abdominal seg-ment, transferred to the thorax in pupation. The thorax of a saw-fly can easily be broken up into its threeconstituent parts of pro-, meso-, and meta-thorax. If the front andmiddle coxse are seized in two pairs of pincers and pulled apart, thepro- and meso-thorax part company. Similarly, by tearing the middlecoxae away from the hind coxae, the meso-thorax can be separatedfrom the meta-thorax. The so-called propodeum, though theoreti-cally an abdominal segment, is so firmly attached to the meta-thoraxthat when the abdomen is broken off (, in a dried specimen by. Fig. 157.—Thorax of a saw-fly: dorsal surface—, as seen from above. (Sketch by Rev. Morice. From Entomologists MonthlyMagazine.) Fig. 158.—Lateral or side view offig. 157. pushing it roughly downwards), the propodeum always remains withthe thorax. In fig. 157, h, Ji, the cenchri are two singular organs with someresemblance to little tegulae. They are always present in Tenthred-inidse, but I cannot find that their function has as yet been belong to the meta-thorax, and mark its base. Regarding the neuration of a saw-flys wing, the first thing to bedone is to realise the course of the longitudinal nervures = the veins,—the thick single lines. It will be seen that they are muchlonger than the transverse = the nerves. They are also moreuniform throughout the whole group, and much less liable to varyabnormally in individual specimens. We commence with them partly 168 FOREST ENTOMOLOGY. on this account and partly because they divide the w
Size: 2365px × 1056px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisheredinburghwblackwoo
