276 
MR.  J.  O.  WESTWOOD  ON  NYCTERIBIA. 
Apterologique',  regarded  it  (under  the  name  of  Phthiridium ')  as  one  of  the  Aptera, 
and  Dr.  Leach,  in  the  '  Supplement  to  the  Encyclopaedia  Britannica,'  formed  for  its 
reception  a  distinct  order,  Notostomata,  in  the  class  Arachnides, — Latreille,  with  that  re- 
markable sagacity  which  he  so  constantly  displayed,  placed  it  in  the  order  Diptera,  next 
to  Hippobosca,  with  the  remark,  "  on  croiroit  que  c'est  une  araignee  k  six  pattes." 
Hence  Mr.  MacLeay  regarded  it  as  occupying  the  osculant  situation  betwen  the  classes 
Arachnida  and  Haustellata. 
But  the  genus  Nycterihia  is  worthy  of  the  attention  of  the  naturahst  on  account  of 
another  peculiarity.  To  say  that  the  insects  of  which  it  is  composed  are  parasitic  upon 
certain  Vertebrata,  would  be  insufficient  to  distinguish  it  from  numerous  other  para- 
sites ;  but  when  it  is  stated  that  this  genus  is  exclusively  confined  to  that  equally  ano- 
malous group — Quadrupeds  we  can  scarcely  call  them — the  Chiroptera,  the  evident  in- 
tention of  Nature  in  preserving  the  system  of  osculant  divisions  cannot  be  overlooked. 
Many  of  the  singular  peculiarities  of  structure  of  this  genus  have  been  ascertained  and 
described  by  some  of  the  most  celebrated  entomologists,  and  the  memoir  of  Hermann 
above  noticed,  that  of  Dr.  Leach  inserted  in  the  '  Zoological  Miscellany '2,  the  article 
Nycteribie  by  Latreille  in  the  '  Nouveau  Dictionnaire  d'Histoire  Naturelle'^,  the  memoir 
by  M.  Leon  Dufour  upon  this  genus  published  in  the  '  Annales  des  Sciences  Naturelles' 
for  April  1831,  and  the  figure  and  description  of  Nyct.  Latreillii  contained  in  Mr.  Cur- 
tis's  '  British  Entomology are  especially  to  be  referred  to. 
Still,  however,  some  of  the  most  important  characters  of  these  insects  remain  involved 
in  uncertainty,  either  from  the  silence  of  authors  respecting  them,  or  from  the  inaccu- 
rate or  insufficient  manner  in  which  they  have  been  described :  among  which  are  to 
be  noticed  the  nature  of  the  transformations  which  they  undergo ;  the  distinction  of 
the  sexes,  and  consequently  the  sexual  characters  and  the  different  organization  of  the 
abdomen  in  the  sexes  ;  the  structure  of  the  mouth,  antennae,  and  eyes  ;  the  separation  of 
the  metasternum  and  abdomen ;  the  situation  and  construction  of  the  spiracles  ;  and  the 
nature  of  the  serrated  organs  between  the  base  of  the  anterior  and  intermediate  legs : 
upon  all  which  points  I  hope  to  be  able  to  offer  to  the  entomologist  satisfactory  details. 
For  the  materials  enabhng  me  to  do  this,  I  have  to  express  my  obhgations  to  Lieut.- 
ColonelW.  H.  Sykes,  who  has  kindly  permitted  me  to  examine  three  female  specimens 
of  the  largest  species  of  the  genus,  brought  home  by  himself  from  the  East  Indies,  and 
preserved  in  spirit ;  to  the  Rev.  F.  W.  Hope,  for  permission  to  examine  two  male 
specimens  of  a  large  species  from  Bengal ;  to  the  Rev.  Leonard  Jenyns,  who  has  pre- 
sented me  with  a  male  of  a  very  distinct  and  moderate-sized  species  from  China  pre- 
'  Published  ia  1 804.  Latreille  had  previously  established  the  genus  under  the  name  of  Nycteribia  in  his 
'  Precis  des  Caracteres  Generiques',  1 795,  and  in  his  'Histoire  Naturelle  des  Insectes  et  des  Crustac^s',  tom.iii. 
An  X.  (1802). 
*  Vol.  iii.  3  Nouv.  Edition,  1818.  *  Plate  277. 
