. Annals of applied biology. Biology, Economic; Biochemistry. K. Hargreaves :U:] are two pairs of thoracic spiracles arranged as in the preceding stage, and two pairs of abdominal situated in the first segment and at the sides of the vasiform orifice respectively. A pair of thick tracheae are given off from the dorsal system with evidence of a pair of spiracles, as in the first instar. Legs (Fig. 19). The legs are much smaller than in the first instar, and they are functionless as ambulatory appendages. Each consists of three segments the homology of which could not be determined with certaint
. Annals of applied biology. Biology, Economic; Biochemistry. K. Hargreaves :U:] are two pairs of thoracic spiracles arranged as in the preceding stage, and two pairs of abdominal situated in the first segment and at the sides of the vasiform orifice respectively. A pair of thick tracheae are given off from the dorsal system with evidence of a pair of spiracles, as in the first instar. Legs (Fig. 19). The legs are much smaller than in the first instar, and they are functionless as ambulatory appendages. Each consists of three segments the homology of which could not be determined with certainty. But it seems probable that the trochanter and tarsus are absent. No spines are present. Antennae (Fig. 20). The antennae are exceedingly small, and each is made up of two segments, the basal one having a short spine near the middle, and the distal one being covered with very short Li^f Fig. 20. Antenna of second instar. Fig. 21. Vasiform orifice and ventral spines. Spines (Fig. 16). In addition to marginal spines there are—a long dorsal pair over the anterior end of the mouth-parts; a short dorsal pair on the first abdominal segment; a long dorsal pair at the anterior corners of the vasiform orifice; a very short pair at the posterior sides of the vasiform orifice; a short ventral pair beneath the vasiform orifice. Vasiform Orifice (Fig. 21). Dorsal pores (Fig. 17). On the dorsal surface are six pairs of pores, which I take to be the openings of the wax glands, the secretion of which covers the general surface of the body. They have a peculiar and characteristic appearance. My preparations were stained with acid fuchsin, and the pores appeared as small dark red rings, surrounded by an area which was of a paler pink colour than the surrounding chitin of the general surface. They are situated as follows: a pair in front of the anterior dorsal spines; a pair each near the thoracic and first abdominal spiracles; a pair in the fourth abdominal segment; a pair at the sid
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