IJM THE ANTEisTN^ AND I'ALPI Of BiPTKllA. 



53 



of the surface cliitin but it continues round the base of the pit 

 unclianged. 



Turning to another species, Xylota sylvarum, a somewhat 

 similar condition is found. In this case, however, the simple pit 

 has no rods of chitin inside, but a few small sensory processes, 

 and is compatible to the sense-pits in many of the foregoing 

 families. The complex j^it of Xylota, howevei% is very large and 

 beautiful ; it possesses an enormous number of sensory processes 



Text-fisure i^5. 



Text-figure 24 



Text-fig. 24. — Oblique section tlnough the top of a sense-pit in the antenna of 

 Xylota sylvarxm. X 980. 



Text-fig. 25. — Senii-diagramniatic longitudinal section through the antenna of 

 Sei'icomi/ia horealis. X 128. 



and almost fills the third joint of the antenna. Text-fig. 23 is a 

 semi-diagrammatic repi-esentation of a longitudinal section of 

 this joint. On the left side of the figure will be seen the large 

 and beautiful pit with its opening and opposite to it the small pit. 

 As the large pit is followed downwards it is seen to divide into 

 two ; the chitinous lining of the pit thickens between the pro- 

 cesses. PI. I. fig. 3 is from a photograph of a transverse section 



