192 



OUR HOUSEHOLD INSECTS 



as the rest. As this preparation is much flattened out, 

 and only its chitinous parts are present, all the rest 

 having been dissolved away, it should be compared with 

 the organ in its natural condition, in order to under- 

 stand the action of the 

 different parts. The 

 proboscis itself consists 

 of three regions (Fig. 

 61), the basal part by 

 which it is hinged to 

 the head, a central part 

 bounded above and be- 



FIG. 61. Side view of Proboscis, partly low by hard chitinous 

 opened, b, basal division; c, central 



rn: 



division ; I, labella) ; m, maxillary palpi, 



portions, and thirdly 

 the two flexible lobes 



which form the extremity of the whole organ, and are 

 called labellae. These will, of course, be closed up like 

 the leaves of a book, and not opened out as seen in the 

 photograph, and their true shape and exquisite structure 

 cannot be made out in this position. Each lobe contains 

 about thirty channels, some of 

 which spring from an inner 

 marginal tube on each side, 

 and all are open to the air by 

 a narrow groove along the 

 under surface. Their form is 

 maintained, and their walls 

 kept in position by numbers 

 of incomplete chitinous rings, 



in the form of a curve, pointed at one end and forked at 

 the other (Fig. 62) ; these are placed alternately in 

 opposite positions, so that, on each side, the forked ends 

 of one series alternate with the undivided ends of the 

 other. This arrangement gives the channels somewhat 



