TICKS, 187 



CASE be remembcredy too, that in some of these blood-suckers, as the 



XII. 



mosquito, it is only the female that attacks us, or indeed that is 

 provided with the sucking apparatus, and there is a very good 

 reason for this. The mission of the male is done as soon as 

 he has impregnated the female, and he may get about his busi- 

 ness, and^die -as soon as he pleases. Nature has no furth-er use 

 for him ; but the female has still to lay her eggs, therefore she 

 must be fed. In, like manner so is only the female tick that 

 we find with its large abdomen distended with blood. The 

 abdomen of the male is not capable of distension like that of the 

 female. 



Eyes are absent in many species of this genus (for example, 

 in our own ticks), but present in others. 



The group is very homogeneous, and although there are various 

 types that may serve for subsections, it does not appear that 

 as yet any very good sectional characters have been found to 

 enable us to break it up, and distribute its numerous species into 

 genera. Koch has tried to do so by the eyes j thus he reserves the 

 name Ixodes for those without eyes ; then he makes a genus 

 Hyalomma for those with clear distinct cone-shaped eyes, and 

 palpi as long or longer than the head ; one named Dermacentor, 

 with small flat moderately clear pale eyes, and very short broad 

 palpi ; one named Amblyomma, with flat muddy dull pale eyes. 

 Starting from these, he uses other characters to differentiate the 

 species still farther ; Hsemalastor has the eyes of Hyalomma, but 

 the body straight in front, without any emargination for the recep- 

 tion of the head, and very long hind legs, and the whole upper 

 surface covered by the shield ; Rhipicephalus has the eyes of 

 Amblyomma, but with the palpi as broad as long, and with an 

 external angle, and so on. But we have already seen the little 

 value of the eyes as a character in some of the other groups, and 

 the whole family is so homogeneous, especially the females, that 

 although some of Koch's sections may be of use as artificial aids 

 to the recognition of species, we cannot regard them as of much 



