36 



BOARD OP AGRICULTURE. 



Figure 29. 



very low, degraded Hemiptera, destitute of wings. The head 

 is small, conical, and narrow ; the thorax is small and in- 

 distinctly separated into segments ; the 

 abdomen is large, flattish, rounded or 

 oval, with nine segments. The antenna 

 are very slender and five-jointed. The 

 eyes are simple and very minute. The 

 feet, or tarsi, have two joints, the 

 last joint forming a strong hook for 

 grasping the hairs firmly while crawling 

 and climbing among it. The mouth- 

 parts form a long and extremely slender 

 fleshy tube, which is retracted when not 

 in use, and is capable of being intro- 

 duced into the skin, for the purpose of 

 sucking blood. The structure of the 

 mouth is as follows, according to 

 Schiodte : u The peculiar attenuation of 

 the head in front of the antennae at once 

 suggests to the practised eye the exist- 

 ence of a mouth adapted for suction. 

 This mouth differs from that of Rhyn- 

 chota [Hemiptera, bed-bug, etc.] gen- 

 erally, in the circumstance that the 

 labium is capable of being retracted into 

 the upper part of the head, which there- 

 fore presents a little fold, which is ex- 

 tended when the labium is protruded. 

 In order to strengthen this part, a flat 

 band of chitine is placed on the under 

 surface, just as the shoemaker puts a 



Figure 29. Proboscis of body-louse (Pediculus corporis DeG6er), entirely pro- 

 truded and seen from above, magnified one hundred and sixty times ; aa, the 

 summit of the head, with four bristles on each side ; bb, the chitinous band, and 

 c, the hind part of the lower lip such as they appear through the skin by strong 

 transmitted light; dd, the foremost protruding part of the lower lip (the haus- 

 tellum); ee, the hooks turned outwards ; /, the inner tube of suction, slightly 

 bent and twisted ; the two pairs of jaws are perceived on the outside as thin 

 lines ; a few blood globules are seen in the interior of the tube. From American 

 Naturalist. 



