. Annals of applied biology. Biology, Economic; Biochemistry. A. W. Rymer Roberts 309 those surrounding the cauda and those of the head are considerably shorter, as in A. sputator. The shape of the spiracles at this stage is very variable and does not give any certain means of separation of the species, though the number of teeth on either side of the orifices has been found to be less in sputator than in ohscurus. In the former these number five in the thoracic, four or five, generally four, in the abdominal spiracles. As in ohscurus the orifices of the spiracle frequently appear to be separa
. Annals of applied biology. Biology, Economic; Biochemistry. A. W. Rymer Roberts 309 those surrounding the cauda and those of the head are considerably shorter, as in A. sputator. The shape of the spiracles at this stage is very variable and does not give any certain means of separation of the species, though the number of teeth on either side of the orifices has been found to be less in sputator than in ohscurus. In the former these number five in the thoracic, four or five, generally four, in the abdominal spiracles. As in ohscurus the orifices of the spiracle frequently appear to be separately margined by a raised border, most evident at the sides, very fine behind and lacking in front. In reality, however, as may be seen under a high-power objective, the margin is patterned on the surface much as in older Text-fig. 1. (rt) Agriotes aputator, L. Mandible of larva in first instar. Magn. cir. x 700. (b) Athons haemorrltoidalis, F. Mandible of larva in late instar, seen from above. (c) Atlioiis haemorrhoidalis, F. Clypeal process or nasale of larva. Magn. cir. x 130. {d) Aiiriotes acuminatux, Steph. Mandible of larva in first instar. Magn. cir. x 770. The median area of the septum between the two orifices is lighter in colour and less strongly chitinized but it is in hke manner furnished with a corrugated pattern, corresponding to the teeth at the sides of the orifice. The ventral orifice is most frequently smaller than the dorsal one, though considerable variation in size and shape occurs. Towards the apex of the 9th abdominal segment the same con- striction is apparent in both this species and A. ohscurus at hatching, but disappears later during the first instar. It may be no more than a coincidence, but among the specimens examined the margins of the sensory pits on the 9th abdominal segment are usually coloured brown at or shortly after hatching, whereas in ohscurus the margins are only to be delimited with difficulty until a much later Please no
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