MOUTH-PARTS OF TICK 



425 



without anv oral appendages, but with two pairs of movable hooks near 

 the mouth.' The muscles are striated. The alimentary canal is very 



Fig. 238.— Mouth-parts of a tick (one of the Ixodida?). — From 

 a Specimen, seen from the veritral aspect. 



I and 2. The capitulum or " false head " from beneath. The transverse line between 

 I and 2 does not seem to have any significance. 



3. The fixing hypostome with recurved teeth, a median process from behind 



the mouth-opening. . 



4. The cutting chelicera, with curious out-turned teeth at the tip. The 



chelicera is sometimes called the mandible. 



5. The blade of the chelicera. 



6. The pedipalp or palp. I.-IV. Its four joints. When the pedipalps are 



apposed, a groove on their inner aspect receives the chelicerae and 

 hypostome. 



simple, without Malpighian tubes. A narrow circumoesophag. al nerve- 

 ring, without a brain, is connected with a single ventral ganglion. 



