186  MR.  W.  S.  MACLEAY  ON  THE  NATURAL  HISTORY  OF  URANIA. 
colour,  sometimes  turning  to  yellow,  bearing  considerable  resemblance  in  form  to  those 
of  the  genus  Catocala  of  Schrank,  particularly  Cat.  nupta^.  They  vary  in  shape  from 
an  ovate  to  an  oblate  spheroid,  but  in  general  are  truly  spherical.  A  circular  space 
on  their  summit  is  smooth,  but  from  the  circumference  of  this  circle  proceed  about 
twenty  four  longitudinal  ribs,  the  intervals  between  which  are  crossed  at  right  angles 
by  obsolete  strics. 
The  young  larv(S  just  emerged  from  the  egg  appear  of  nearly  the  same  pale  green 
colour,  and  have  seven  longitudinal  black  lines,  which  the  microscope  shows  to  be  so 
many  rows  of  long  black  hairs.  The  head  of  these  young  larva  is  of  a  dirty  yellowish 
colour,  but  after  the  first  month  it  assumes  its  true  appearance.  This  caterpillar 
scarcely  ever  rolls  itself  into  a  ring,  and  when  full  grown  is  about  I4  to  2  inches  long, 
of  a  regular  cylindrical  form,  with  the  more  usual  sixteen  feet.  Its  head  is  now  red, 
polished,  and  sessile,  that  is,  not  set  on  the  body  by  means  of  a  narrow  neck,  as  in  the 
larva  of  true  Hesperida.  This  head  has  black  mandibles,  and  is  besides  irregularly 
sprinkled  with  some  black  spots,  of  which  four  placed  close  together  nearly  at  the  apex 
of  the  triangle  which  crowns  the  clypeus,  and  one  on  each  side  marking  the  site  of  the 
ocelli,  seem  to  be  tolerably  constant.  The  other  spots  on  the  head  are  merely  black 
points,  generally  about  twelve.  The  first  segment  of  the  thorax,  or  prothorax,  is,  as  in 
many  Lepidopterous  larva,  of  a  more  corneous  texture  than  the  other  segments,  and 
more  or  less  of  a  velvety  black  colour,  which  is  diversified  by  a  white  dorsal  line,  and 
two  or  three  white  irregular  spots  at  the  sides.  This,  however,  is  only  the  typical 
colouring  of  the  prothorax;  for  in  many  specimens  the  white  is  more  predominant  than 
I  have  described,  and  is  accompanied  with  a  slight  red  spot  on  the  back  of  the  seg- 
ment. 
The  true  feet  are  red  ;  and  the  ten  false  feet  are  of  the  same,  only  somewhat  paler, 
tint  as  the  body,  which  varies  from  a  pale  yellowish  green  to  a  flesh  colour,  with  five 
paler  longitudinal  lines,  of  which  the  middle  one  is  dorsal. 
The  mesothoracic  segment  is  rarely  spotted,  but  all  the  others  are  often  marked  more 
or  less  with  black  spots,  particularly  the  antepenultimate  segment,  which  scarcely  ever 
occurs  without  two  lateral  black  spots  placed  immediately  above  the  penultimate 
stigma.  These  spiracles  are  usually  black,  and  the  whole  body  moderately  hairy,  that 
is,  having  on  each  segment  about  six  hairs,  which  are  white  and  about  one  fifth  as 
long  as  the  whole  body. 
It  is  by  no  means  easy  to  make  a  tolerably  accurate  description  of  this  caterpillar, 
because  there  are  few  larva  of  the  same  species  which  differ  so  much  from  each  other 
in  colour,  size,  and  marking,  as  those  of  Ur.  Fernandina.    It  is  perhaps  most  readily 
'  This,  in  fact,  appears  to  be  a  very  common  form  of  Lepidopterous  egg.  To  this  form  I  assign  those  eggs 
figured  badly  by  Reaumur,  vol.  ii.  tab.  3.  figg.  6.  &  7.  These,  however,  appear  to  want  the  clear  circular  space 
on  the  summit,  and  besides  are  not  so  spherical  as  the  eggs  of  Urania. 
