parasites in Nest of Bomhus derhameUus. 



119 



and on longer tubercles, between the pro- and meso- 

 thorax; the other pairs, on the first 8 abdominal seg- 

 ments, near the hind angles, just dorsal to the lateral 

 setigerous tubercles. Pedunculate spiracles are also found 

 in the larvae of certain other Nitidulids (12, p. 472) and 

 in that of Nosodendron (12, pp. 445, 4G9, etc.), which, like 

 many Nitidulid larvae, lives in running sap. 



The apical part of each peduncle is chitinised and pig- 

 mented, forming a dark brown ring (fig. 6 A, b), within 

 which, on the actual summit, is an area of pale membrane 

 enclosing the spiracle itself. The latter is biforous, con- 



Fig. G. — E. depressa, larva. A, spiracle between pro- and meso- 

 thorax, in surface view, X 530 : the outer shaded ring is the pigmented 

 part of the apex of the tubercle; the unshaded area mthin this repre- 

 sents colourless membrane suiTounding the spiracle itself. B, spiracle 

 on 1st abdominal segment, X 530 : shown in profile, partly in optical 

 section, the pigmented band round tJic apex of the tubercle being left 

 incomplete in front; tr., trachea. Both arc drawn from a larva cleared 

 with potash and mounted in balsain. 



sisting of two contiguous chambers, the side walls of 

 which present a transversely striated appearance, clearly 

 seen in profile (fig. 6 b) and indicated also in surface-view 

 (fig. 6 a). The chambers have a common partition wall, 

 though in the position from which fig. 6 b is drawn (oblique 

 profile) they seem to some extent separate. Their tops 

 appear at first sight to be open as two long narrow slits, 

 but on closer examination it is seen that the aperture is 

 only at one end, and occupies less than half the length of 

 the chamber, the rest of which has a thin unstriated roof. 

 The two openings appear as though united at their bases 

 into a single U-shaped orifice : but this union is only 

 apparent, due to a sudden break or thinniug in the chitiu 



