Packard] RELATIONS OF INSECTS TO MAN. 



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When looking about for a weak place in the skin of his 

 host the creature alights upon a sweat pore. Into this he 

 plunges his sucker, and anchors it there i^ig- 5"). 



by a number of hooks (Fig. 55, ee). 

 After they have firmly grasped the 

 surrounding flesh the first pair of bris- 

 tles (the real mandibles transformed) 

 are protruded (we are quoting Prof. 

 Schiodte here almost word for word, as 

 given in the "American Naturalist," 

 vol. iv, p. 86). These bristles are 

 towards their points united by a mem- 

 brane so as to form a closed tube. 

 AVhen the whole instrument is exserted, 

 we perceive a long, membranous, flex- 

 ible tube (the portion from e-f and 

 including the end) hanging down from 

 the under lip (labium), and along the 

 walls of this tube the bristle-like jaws 

 in the form of narrow bands of chitine. 



In this way, says Schiodte, the suck- 

 ing tube can be made longer or shorter 

 as required, and easil}^ adjusted to the 

 thickness of the skin in the particular 

 place where the animal is sucking, 

 whereby access to the capillary system 

 is secured at any part of the body. 

 "It is apparent from the whole struc- 

 ture of the instrument, that it is by no 

 means calculated for being used as a 

 sting, but is rather to be compared to 

 a delicate elastic probe, in the use 

 of which the terminal lobes probably 

 serve as feelers. As soon as the capillary system is reached, 

 the blood will at once ascend into the narrow tube, after 



5 



MouUi of a Louse, 



