MR.  J.  O.  WESTWOOD  ON  NYCTERIBIA. 
283 
contracted  behind  the  basal  articulation.  Its  coriaceous  part  in  Colonel  Sykes's  in- 
sects is  covered,  both  above  and  beneath,  with  minute  shining  black  tubercles,  four  of 
which,  on  the  centre  of  the  abdomen,  are  of  a  larger  size,  and  occupy  a  small  naked 
portion.  It  is,  moreover,  densely  clothed,  on  the  upper  side  only,  from  about  one  third 
of  the  distance  from  the  extremity  to  the  tip,  with  long  and  strong  dark  reddish  bristles, 
each  arising  from  a  similar  tubercle :  at  each  side  above,  between  the  basal  corneous 
articulation  and  the  setose  terminal  portion,  three  circular  spiracles  are  to  be  observed. 
Another  spiracle  of  a  similar  size  exists  on  each  side  in  the  midst  of  the  bristly  region, 
and  a  pair  more  minute  near  the  anus  :  thus  at  least  five  pairs  of  abdominal  spiracles 
exist,  although  no  traces  of  articulation  are  visible.  It  is  to  be  observed,  however, 
that  the  tubercles,  in  two  or  three  places,  are  arranged  in  transverse  lines,  so  as  to 
give  the  appearance  of  indication  of  segments  :  these  lines,  however,  do  not  appear  to 
correspond  with  the  spiracles. 
The  anus  is  situated  at  the  extremity  of  the  body.  It  is  circular,  slightly  protruded, 
and  consists  of  two  lateral  horny  lunate  plates,  behind  which  a  smaller  circular  space 
is  observable,  with  a  smaller  and  more  distant  pair  of  corneous  flattened  plates. 
Such  is  the  organization  of  the  abdomen  of  the  female  :  and  in  order  to  remove  any 
doubts  which  might  remain  as  to  the  identity  of  the  sex,  I  shall  now  proceed  to  notice 
the  nature  of  the  transformations  which  the  insects  undergo.  No  direct  statement 
derived  from  actual  observation  has  hitherto  been  made  upon  this  subject.  Some 
authors  have,  indeed,  correctly  surmised,  from  their  evident  connexion  with  the  Hippo- 
boscida,  that  they  were  pupiparous  ;  but  Latreille  regarded  them  as  differing  from  that 
family  in  this  respect,  "  il  paroit  cependant  qu'elle  ne  subit  pas  de  metamorphoses, 
qu'elle  croit  a  la  maniere  des  poux,  des  araignees,  ayant  trouve  en  meme  tems,  sur  une 
chauve-souris,  des  individus  de  cet  insecte  tres-petits  et  peu  ages"i ;  an  opinion  which 
he  expressed  in  several  of  his  subsequent  works.  Anxious  to  ascertain  the  correctness 
of  this  supposition,  I  selected  the  specimen  whose  abdomen  was  most  distended  ;  and 
on  making  an  aperture  on  its  under  side,  I  extracted  without  difficulty  a  hard  organized 
mass,  of  a  white  colour  and  nearly  as  large  as  the  abdomen  itself,  of  an  oval  form,  con- 
vex above  and  flattened  beneath,  with  the  broadest  extremity  offering  three  small  cir- 
cular spots  placed  in  a  triangle,  with  two  smaller  ones  placed  at  a  greater  distance  from 
them  :  the  sides  of  the  body  also  exhibited  the  traces  of  five  articulations.  That  this  was 
the  young  of  the  Nycteribia  in  its  pupa  state,  similar  to  that  of  the  Hippoboscida,  cannot 
be  doubted.  I  regret  that  it  was  not  in  a  sufficiently  forward  state  of  organization  to 
allow  of  my  opening  it,  with  the  view  of  extracting  the  inclosed  Nycteribia. 
Bearing  in  mind,  therefore,  that  in  the  only  individuals  of  the  genus  whose  sex  has 
thus  been  ascertained,  the  abdomen  of  the  female  is  distinguished  by  the  want  of  articu- 
VOL.  I. 
'  Hist.  Nat.,  torn.  xiv.  p.  401. 
2  p 
