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XXXIII.  Characters  and  Description  of  a  new  Genus  of  the  Family  Melolonthidge.  By 
John  Curtis,  Esq.,  F.L.S.,  S^c.    Communicated  by  the  Secretary. 
Read  February  10,  1835. 
In  a  collection  of  insects  sent  to  me  by  Mr.  A.  Mathews,  and  formed  by  him  in  Lima 
and  its  neighbourhood,  the  following  species  appeared  to  me  so  peculiar  in  its  struc- 
ture that  I  thought  it  particularly  worthy  of  being  described  and  figured, 
Ordo  COLEOPTERA. 
Fam.  Melolonthid/E,  MacLeay. 
Genus  Ancistrosoma 
AntenntE  in  utroque  sexu  similes,  maris  paulo  majores,  in  clypei  basin  ante  oculos  in- 
sertse,  capite  breviores,  pilosse,  clavatse,  9-articulatse,  a'rticulo  basali  longo,  crasso, 
clavato,  pilosissimo,  secundo  parvo,  tertio  tribus  sequentibus  longiore,  his  sub- 
obovatis,  sexto  majore  et  subcyathiformi,  tribus  apicalibus  clavam  lamellosam  me- 
diocrem  etFormantibus. 
Labrum  transversum,  semiovatum,  crassum,  setosum,  in  medio  leviter  emarginatum. 
Mandibulee  subsimiles,  ad  basin  crassse,  disco  circulari  piano,  transversim  sulcato,  apice 
elongato,  fortiter  incurvato,  obtuso  et  leviter  bidentato,  extern^  pilosse,  margine 
interno  membranaceo,  dense  ciKato. 
Maxillce  similes,  dentibus  quinque  validis,  lobi  interioris  apice  sextum  simulante.  Palpi 
maxillares  breves,  4-articulati,  articulo  basali  reliquis  minore,  secundo  clavato  ter- 
tio longiore,  hoc  obtrigono  piloso,  quarto  majore,  ovato-conico. 
Mentum  concavum,  pilosum,  orbiculari-quadratum,  in  medio  angulatum. 
Labium  breve,  corneum,  transversum,  leviter  emarginatum,  ciliatum.  Palpi  labiales 
parvi,  ad  labii  basin  utrinque  inserti,  3-articulati,  articulo  basali  subgloboso,  minu- 
tissimo,  secundo  paulo  majore,  tertio  duplo  longiore,  elliptico,  gracili. 
Caput  suborbiculare  :  cZi/pews  incrassatus,  ad  apicemrecurvus,  maris  profundi  foemiuce 
leviter  in  medio  emarginatus  :  ocuU  parvi,  ovati,  laterales,  verticales,  antic^  emarginati. 
TAofca;  con vexus,  marginatus,  hexagonus  (prsesertim  in  mare),  ad  angulos  anteriores 
productus,  angulis  posterioribus  subacuminatis,  dente  brevi  in  baseos  medio  lateribus- 
'  "AyKi(7Tpoy,  harms;  awfxa,  corpus. 
