43 
ticks  do,  and  in  such  elevated  positions  await  some  passing  host. 
When  once  the  larva  has  secured  a  host,  it  feeds,  and  after  repletion 
casts  its  skin  and  becomes  a  nymph.  In  this  latter  stage  it  takes 
another  meal  of  blood,  afterwards  casting  its  skin,  and  this  brings  it 
to  the  sexually  mature  stage.  So  that  all  its  meals  and  both  its 
moults  are  effected  on  one  host.  Pairing  also  takes  place  on  the 
host ;  and  in  a  very  large  percentage  of  cases  the  male  takes  up  a 
position  close  to  the  nymphal  female,  considerably  in  advance  of  the 
time  when  the  latter  undergoes  her  last  moult  and  becomes  sexually 
mature.  This  habit  seems  to  be  quite  general,  though  almost  any 
number  of  adult  couples  may  also  occur  on  the  same  host.  As  in  the 
case  of  the  ‘  silver  tick  ’  (^Amblyomma  cajanense),  no  observations 
were  made  as  to  the  parasitic  period.  But  it  was  found  that  egg 
laying  takes  place  in  from  seven  to  fourteen  days  after  the  replete 
female  is  removed  from  the  host,  and  that  the  larvae  or  grass  lice 
begin  to  hatch  on  the  thirty-fifth  day  and  continue  to  do  so  till  the 
forty-second  day.  So  that  the  length  of  the  non-parasitic  stage  may 
be  given  as  fifty-six  days  during  the  dry  season.  The  number  of  eggs 
laid  by  the  female  varies  from  i,ooo  to  2,000  approximately. 
It  is  by  far  the  most  abundant  tick  in  the  Island ;  and  from  90  to 
95  per  cent,  of  the  species  found  on  cattle  were  of  this  kind. 
Hosts.  The  ox  is  the  principal  host  of  this  tick,  both  in  Jamaica 
and  elsewhere  outside  the  Island.  In  three  instances,  mature 
examples  of  both  sexes  were  found  on  the  dog,  associated  with 
Rhipicephalus  sanguineus]  several  adults  and  nymphs  were  also 
found  on  the  horse,  but  the  females  from  this  host  were  much  smaller 
than  those  taken  either  from  cattle  or  dogs.  It  is  generally  believed 
that  the  larval  or  ‘  grass  lice  ’  stage  will  attack  any  vertebrate  animal 
that  comes  in  its  way.  It  is  in  this  stage  that  it  is  such  a  great  pest 
to  man. 
Distribution.  Occurs  everywhere  in  the  grazing  district  through¬ 
out  the  Island.  Specimens  were  obtained  in  all  the  parishes ;  the 
only  locality  from  which  specimens  were  not  received,  was  Water 
Valley,  a  banana  property  in  the  Parish  of  St.  Mary,  though  it  was 
swarming  elsewhere  in  the  district  a  few  miles  away.  So  far  as  one 
could  ascertain  it  did  not  occur  at  a  greater  altitude  than  2,000  to 
3,000  feet,  but  this  requires  confirmation. 
