THE MORE IMPORTANT FAMILIES OF ACARl. 



107 



rostrum, which is inserted into the host. The four remaining joints of each 

 maxilla form together the (maxilhirj) palp ; the two palps are more or less 

 excavate on the side toward the rostrum (see fig. 3, ventral side), thus 

 forming a sheath wherein the rostrum is secured during the periods that the 



Fig. 3. — JRhipicephalus mnguineus (Latr.) ; female ; dorsal and ventral side ; S=stigraa ; 

 r=:peritrema. — Original. — A noxious species. 



creature lives free. The eight legs are stout, ending in two strong claws, 

 and are placed contiguously on each side. — As is shown in fig. 4 (ventral 

 side), the genital aperture lies far forward. During copulation the ventral 

 surfaces of the two sexes are apposed. As soon as the female is impregnated 

 it gorges itself with blood from its host and becomes enormously distended. 



1^^^=^. 



Fig. 4. — Ornithodonis mouhatd, Murray; female; dorsal and ventral side; S = stigma. 

 Copied from Doflein, Protozaenkunde, 1909. — A noxious species. 



sometimes even attaining the size of a hazel-nut. It then loosens its hold 

 and falls to the ground, where it seeks shelter under stones, dead leaves, etc., 

 for the purpose of ovipositing. In fig. 3 (dor^-al side) it will be observed 

 that the female has on its neck, behind the palps, two dull patches. Out of 

 these patches grow two white or transparent sausage-shaped organs, which 



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