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MR.  J.  O.  WESTWOOD  ON  NYCTERIBIA, 
Mr.  Curtis  thus  generically  describes  the  abdomen  :  "  Conic-depressed,  composed  of 
6  ciliated  joints  in  the  male,  the  last  joint  hollow  beneath,  producing  a  style  in  the 
centre,  and  terminated  by  two  incurved  pilose  laminse"  ;  thus  omitting  all  notice  of  the 
structure  of  the  female  abdomen.  And  his  figure  of  Nyct.Latreillii  exhibits  a  dilated  six- 
jointed  abdomen,  the  last  joint  being  the  longest,  and  rounded  at  the  extremity,  and  with 
an  additional  transverse  series  of  bristles  at  the  base,  indicating  another  basal  segment. 
He  has  not  represented  the  organs  which  he  describes  as  belonging  to  the  male. 
I  now  proceed  to  notice  more  concisely  the  peculiarities  of  organization  in  the 
species  which  I  have  myself  examined. 
Mr.  Hope's  Bengal  insects  are  somewhat  smaller  than  Colonel  Sykes's  ;  but  the 
structure  of  all  their  parts  (except  the  abdomen)  is  so  similar  that  I  should  even  be  in- 
clined to  regard  the  former  as  the  males  of  the  latter.  The  abdomen  is  elongate- 
ovate,  and  conically  produced  to  the  extremity,  where  it  is  shortly  truncate.  It  is  com- 
posed of  five  joints,  the  last  of  which  is  furnished  beneath  with  two  elongated  and  gra- 
dually attenuated  styles,  which,  in  the  dried  state  of  the  insect,  are  incurved  and  laid 
flat  upon  the  under  side  of  the  joint  :  they  are  very  slightly  pilose,  and  from  their  being 
laid  close  together  it  is  impossible  to  obtain  a  knowledge  of  any  other  internal  organ 
which  they  probably  conceal. 
In  my  Chinese  species  the  abdomen  is  nearly  oval,  with  the  terminal  segment  some- 
what narrovvTcd.  It  is  furnished  above  with  six  transverse  series  of  bristles  placed  at 
equal  distances,  giving  the  appearance  of  seven  segments ;  but  on  closely  examining 
them,  the  abdomen  certainly  does  not  exhibit  any  corresponding  articulations,  in  the 
ordinary  acceptation  of  that  word,  the  tegument  being  continuous.  The  terminal  seg- 
ment is  furnished  at  its  extremity  with  a  pair  of  elongated  styles,  applied  close  together, 
bent  downwards,  and  slightly  pilose  ;  and  beneath  these,  arising  from  the  base  of  the 
joint  beneath,  is  an  exserted  and  elongated  fleshy  style,  dilated  at  the  tip.  This  con- 
struction is  very  similar  to  that  of  Hermann's  supposed  males  and  to  Mr.  Curtis's  de^ 
scription  of  the  male  of  Nyct.  Latreillii,  and  is  evidently  characteristic  of  the  male  sex. 
The  bristles  v/hich  arm  the  extremity  of  the  palpi  are  very  long,  and  the  anterior 
coxa  are  much  shorter  than  in  the  preceding  species. 
In  one  of  Mr.  Stephens's  dried  specimens  of  Nyct.  Latreillii,  the  abdomen  is  more  linear 
than  in  Mr.  Curtis's  figure,  but  is  divided  into  six  segments  of  nearly  equal  size,  except 
the  last,  which  is  more  conical  and  truncate  at  the  tip,  and  is  furnished  beneath  with 
two  lamina,  placed  rather  apart  so  as  to  exhibit  a  small  central  style.  They  are,  how- 
ever, closely  applied  to  the  under  surface  of  the  segment.  This  is  evidently,  therefore, 
a  male :  but  the  other  specimen  is  very  differently  constructed  ;  the  abdomen  is  elon- 
gate-ovate, its  upper  surface  exhibiting  a  large  and  smooth  oval  patch,  ciliated  at  the 
extremity,  and  extending  over  more  than  one  third  of  the  base  of  the  abdomen  :  this  is 
followed  by  a  densely  pilose  region  extending  beyond  half  the  length  of  this  part  of  the 
body  ;  then  follows  another  transverse  region,  denuded  of  hairs,  but  ciliated  at  its  ex- 
