518 



Genus Haenuqjhf/salls 



NOTES ON THE BIOLOGY OF HAEMAPHYSALIS 



By G. H. F. NUTTALL. 



Referring to the list of 50 species and varieties enumerated in the 

 table at the end of this fasciculus, the table serving likewise as an 

 index, the reader will find that the various stages of each species and 

 variety known to science give the following figures : The 



(/ $ o Z are known in 14 species and varieties. 



^ o „ „ 

 c/* only 



■f >) )) )) 



It follows that these species and varieties are known by 45 ^f, 41 $, 

 19 o, and 14 L. 



By referring to Part II, p. 295, it will be seen that 51 species and 

 varieties of Lrodes are known by 21 (/, 48 $, 22 o and 14 X. These 

 figures show that a marked difference exists between the two genera. 

 The number of J's of HaeiiKqjhysalis which are known is slightly 

 greater than that of the $.s, this being evidently due to the habit 

 of the (/s to remain upon the host which the $s have abandoned; this 

 habit is also indicated by certain field observations on //. cinnnharina 

 var. punctata, H. concinna and H. inermis, where (fs only have been at 

 times found upon the host. In Ixodes on the other hand, some (/s do 

 not attack the host (see Part II, pp. 334-345), and this accounts for the 

 preponderance of $s that are known to science, although the cf^ of 

 some species frequently occur in copula upon the host and abandon the 

 latter together with the $ . 



Reference to pp. 507-511, where we have listed the hosts upon 

 which HaemupJnjsalis occur, seems to show that the members of this 

 genus are less specialized in respect to hosts than are Ixodes. 



The life-history, in Haemaphysalis, appears to agree in the main 

 with that outlined for Ixodes (see Part II, p. 295) but it is impossible 

 to generalize since we only know the life-history of six species and 

 varieties of Haemaphysalis, and in H. inenins we have a species whose 

 life-history, in the present state of our knowledge, is imique amongst 

 the Ixodoidea. 



