﻿274 
  Mr. 
  R. 
  C. 
  L. 
  Perkins 
  on 
  

  

  A 
  . 
  btfcephala 
  is 
  remarkable 
  for 
  its 
  highly 
  aberrant 
  genital 
  

   armature 
  in 
  the 
  male, 
  while 
  its 
  $ 
  is 
  quite 
  normal; 
  ferox 
  

   for 
  the 
  highly 
  developed 
  floccus 
  and 
  scopa 
  in 
  the 
  female, 
  

   while 
  its 
  male 
  is 
  comparatively 
  closely 
  allied 
  to 
  spinigera. 
  

  

  Group 
  of 
  A. 
  VARIANS. 
  

  

  This 
  group 
  is 
  rather 
  well 
  represented 
  with 
  us, 
  and 
  the 
  

   chief 
  character 
  of 
  the 
  males 
  is 
  to 
  be 
  found 
  in 
  the 
  head 
  

   and 
  mandibles. 
  The 
  latter 
  are 
  always 
  long 
  and 
  falcate, 
  

   the 
  tips 
  forming 
  a 
  very 
  distinct 
  cross, 
  never 
  resting 
  one 
  

   along 
  the 
  other. 
  In 
  most 
  of 
  the 
  species 
  the 
  mandibles 
  

   are 
  also 
  armed 
  with 
  a 
  distinct 
  angulation 
  or 
  tooth 
  on 
  their 
  

   lower 
  edge 
  at 
  the 
  base, 
  and 
  the 
  lower 
  occipital 
  angles 
  of 
  

   the 
  head 
  are 
  strongly 
  produced 
  backwards 
  in 
  a 
  pointed 
  

   form, 
  the 
  latter 
  character 
  being 
  conspicuous 
  also 
  in 
  those 
  

   which 
  lack 
  the 
  basal 
  mandibular 
  tooth. 
  

  

  But 
  in 
  A. 
  clarkella 
  the 
  form 
  of 
  the 
  head 
  is 
  less 
  remark- 
  

   able, 
  though 
  after 
  removal 
  of 
  the 
  pubescence 
  it 
  can 
  easily 
  

   be 
  seen 
  that 
  the 
  structure 
  approaches 
  that 
  of 
  the 
  other 
  

   members 
  of 
  its 
  group, 
  the 
  lower 
  occipital 
  angles 
  being 
  

   hardly 
  at 
  all 
  rounded 
  off. 
  Alfken 
  wrongly 
  separates 
  this 
  

   species 
  from 
  the 
  varians 
  group 
  and 
  places 
  it 
  next 
  to 
  nigro- 
  

   aenea, 
  Saunders 
  places 
  it 
  next 
  to 
  fulm, 
  but 
  then 
  separates 
  

   these 
  from 
  their 
  proper 
  allies 
  by 
  interposing 
  nigroaenea 
  

   gwynana 
  and 
  angustior, 
  an 
  unnatural 
  arrangement. 
  The 
  

   species 
  is 
  best 
  placed 
  next 
  to 
  apicata, 
  in 
  my 
  opinion. 
  

   Some 
  of 
  the 
  males 
  of 
  this 
  group 
  have 
  the 
  tubercle 
  of 
  the 
  

   labrum 
  upturned, 
  as 
  in 
  the 
  next 
  following, 
  but 
  the 
  different 
  

   shape 
  of 
  the 
  head 
  and 
  other 
  characters 
  readily 
  separate 
  

   them. 
  The 
  females 
  are 
  also 
  quite 
  distinct 
  as 
  a 
  group 
  

   by 
  the 
  entirely 
  rugulose 
  surface 
  sculpture 
  of 
  the 
  abUomen, 
  

   nowhere 
  polished, 
  its 
  feeble 
  puncturation, 
  long 
  pubescence 
  

   on 
  the 
  1st 
  and 
  middle 
  part 
  of 
  the 
  2nd 
  segment 
  at 
  the 
  

   least, 
  together 
  with 
  the 
  characters 
  afforded 
  by 
  the 
  perfect 
  

   floccus, 
  and 
  the 
  sharply 
  raised 
  triangular 
  middle 
  part 
  of 
  

   the 
  pygidial 
  area. 
  The 
  genital 
  armature 
  of 
  the 
  male 
  has 
  

   the 
  lobes 
  of 
  the 
  stipites 
  well 
  produced 
  at 
  the 
  inner 
  apical 
  

   angle, 
  but 
  not 
  acutely, 
  and 
  the 
  sagittae 
  are 
  always 
  widened 
  

   by 
  a 
  rounding 
  of 
  their 
  sides 
  at 
  the 
  base. 
  The 
  5th 
  antennal 
  

   joint 
  is 
  never 
  very 
  short 
  and 
  often 
  sUghtly 
  elongate. 
  

  

  The 
  males 
  of 
  this 
  group 
  show 
  some 
  af&nity 
  to 
  that 
  of 
  

   trimmerami, 
  but 
  it 
  is 
  probably 
  more 
  closely 
  allied 
  to 
  the 
  

   following. 
  

  

  