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bundle of five long bristles (a);- further, on the dorsal side, two 
very stiff, long bristles (6). Dorsally on the hindedge of the an- 
terior part we find two slightly chitinized, almost cushion-shaped 
Fig. 23. Sipho seen dorsally. 
parts, each carrying an elegantly curved, very movable bristle 
(c).. Two other bristles, not so conspicuøus (d), are situated Im- 
mediately above the bore-tube. A more thorough examination of 
the organs is rather difficult owing to the very hard chitin. The 
two strong tracheal trunks (e, e1) are in the sipho united in 4 
common trunk transformed into an internal tube (e2) (fig. 25) act 
