435 ////: AMERICAN NATU&ALIS1 [VOL. XLVI 



IM.MI-XITY TO THE TKXAS CATTI.I: TICKS 

 I am able fully to confirm Mr. Borden's statements 

 (foe. rit.) that the pure Brahma cattle and the hybrids 

 are perfectly immune to the Texas cattle tick. Fig. 8 

 shows the ordinary conditions of the native Durham or 

 HerelWd rattle, while Figs. '.), 1 and :! show the condi- 



Fio. 8. 



A tlck-ini'i'sti'il llerefnnl 



COW. 



Kir,. 0. A Bos indictts cow free 

 from ticks. 



Karh of these cows has suckled a calf (lurini; HIM sumniMi- and hotli 

 have been together in the same pasture. 



tions of the pure Brahma and hybrids all running 

 together on the same range. I was not able to ascertain 

 definitely the inheritance behavior of this character (im- 

 munity to ticks) in the F 2 progeny. However, it is ex- 

 pected that data on this point will be available in the 

 or summer of 191 



SIZE AND PROLIFICNESS 



The statement by Mr. Borden (loc. cit.) that the 

 hybrids running on the range average about 50 per cent. 



