14 R. T. LEWIS ON A SPECIES OF IXODES. 



wards the apex, and terminating witli a curved spear-shaped 

 tooth, flanked at a short distance helow by two others, the 

 points of which are very fine and slightly recurved. These 

 denticulations, like the others, also point outwards, and when 

 withdrawn within the sheath the flat back of the first blade lies 

 within the hollow of the second for mutual protection and 

 economy of space (Fig. 8). 



The structure of the entire arrangement suggests the modus 

 operandi to be as follows : An incision made in the epidermis by 

 the first pair of mandibles is enlarged and cleared by the scoop- 

 like blades of the second pair, the tapering end of the rostrum 

 being inserted and continually pushed forward into the orifice 

 until the blood-vessels are reached, and in like manner cut 

 through. By the muscular expansion of the abdomen (?) the 

 blood is then freely drawn up the suctorial tube, formed by the 

 groove between the labium and the under surface of the sheath. 

 The resistance offered to any forcible withdrawal by the holding 

 power of the forty-two barbs on the labium is sufficiently 

 obvious, and, apart from such inflammatory action as might 

 arise from the labium being broken off and left embedded in the 

 flesh, it seems clear that in any case a wound so produced would 

 be a source of more lasting annoyance than the more cleanly 

 cut incision of the familiar flea. 



Although I have not been able to find this species figured in 

 either of the illustrated works consulted, it would be rash to 

 assume at present that it has not hitherto been either named or 

 described. Otherwise I should venture to propose that it be 

 called Ixodes varani, as indicating the source of supply. 



Explanation of Plate I. 



Fig. 1. — Dorsal view of tick, x 20 



„ la. — „ „ natural size 



„ 2. — Rostrum — lateral view, x 45. 



„ 3.— „ —dorsal „ 



„ 4.— „ —ventral „ 



„ 5. — „ —end „ „ 



„ 6. — Inner mandible — right side, dorsal aspect. 



„ 7.— Outer „ „ „ 



„ 8. — 6 X 7 shown in situ. 



