288 
MR.  J.  O.  WESTWOOD  ON  NYCTERIBIA. 
as  respects  the  sexual  characters,  in  a  manner  completely  different  from  that  of  any  of 
the  other  species,  and  that  those  individuals  which  exhibit  the  least  traces  of  abdominal 
articulations  are  females. 
It  would  seem  that  Montagu  was  induced  to  regard  the  externally  styliferous  speci- 
mens as  males,  not  only  from  the  existence  of  these  styles,  which  he  evidently  regarded 
as  masculine  organs,  but  from  the  larger,  tumid  and  ovate  form  of  the  abdomen  of  the 
other  specimen,  which  he  conceived  to  be  a  female.  The  latter  circumstance,  however, 
is  visible  in  the  specimen  at  the  British  Museum,  and  may  easily  be  accounted  for  by 
supposing  that  the  other  specimens  are  females  in  an  unimpregnated  state. 
It  is  also  to  be  observed,  that  in  the  females  of  Nyct.  Latreillii  we  have  seen  that  the 
structure  of  the  terminal  portion  of  the  abdomen  exhibits  somewhat  of  an  incipient  ap- 
proximation to  that  of  the  styliferous  abdomen  of  the  female  of  Montagu's  species. 
Dr.  Leach's  specimen  of  Nyct.  Blainvillii,  preserved  at  the  British  Museum,  is  evi- 
dently a  male  :  it  has  the  abdomen  of  an  elongated  conical  form,  exhibiting  five  trans- 
verse series  of  bristles,  and  having  the  terminal  joint  somewhat  larger  than  the  pre- 
ceding, with  the  extremity  truncate  and  the  angles  not  acute.  Being  gummed  down 
upon  paper,  I  could  not  examine  its  under  side. 
Mr.  Royle's  East  Indian  species  is  a  male,  having  an  elongate-conic  abdomen,  truncate 
at  the  tip,  and  with  the  under  side  of  the  terminal  segment  furnished  with  two  incurved 
styles. 
In  conclusion,  I  beg  leave  to  offer  the  following  synopsis  of  the  species,  first  pre- 
mising, that  in  all  probability,  as  in  the  Pediculida,  the  species  are  much  more  numer- 
ous than  has  hitherto  been  supposed ;  and  that  the  accounts  given  by  early  authors  are 
so  deficient  in  minute  precision  that  it  is  impossible  to  decide  as  to  the  species  described 
by  them.  For  this  cause,  as  well  as  on  account  of  its  being  apphcable  to  the  whole 
genus,  I  have  followed  the  example  of  Dr.  Leach  in  rejecting  the  specific  name  of  Ves- 
pertilionis. 
1.  Nycteribia  Sykesii. 
Nyct.  rufo-picea,  thoracis  tegumento  dorsali  abdomineque  obscure  albicantibus ;  hoc  tuber- 
culis  minutissimis  nigris  undique  tecto  quorum  quatuor  majora  in  quadrangulo  cen- 
trali  disposita,  segmentis  (unico  basali  excepto)  destituto,  apice  pilis  rigidis  ferru- 
gineis  elongatis  obtecto ;  pedibus  elongatis,  subcompressis,  paullo  dilatatis,  breviter 
setosis,  femoribus  magis  ferrugineis,  coxis  anticis  elongatis  tibiisque  apicem  versus  at- 
tenuatis ;  pectinibus  thoracis  elongatis ;  oculis  e  tuberculis  quatuor  compositis.  (?) 
Long.  corp.  lin.  24-. 
Hab.  in  India  Orientali. 
Mus.  Dom.  Sykes. 
Species  maxima. 
