﻿480 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  & 
  Sectors 
  of 
  the 
  arculus 
  (veins 
  M1-3 
  and 
  M4 
  ) 
  distinctly 
  separate 
  at 
  their 
  

   tj 
  ; 
  ,' 
  r^oparture 
  from'^the 
  arculus; 
  anal 
  loop 
  elongate, 
  but 
  not 
  distinctly 
  foot- 
  

   shaped, 
  the 
  toe 
  part 
  being 
  little 
  or 
  not 
  at 
  all 
  developed 
  ; 
  the 
  last 
  antenodal 
  

   cross 
  vein 
  extending 
  from 
  the 
  costal 
  to 
  the 
  radial 
  veins 
  (except 
  in 
  D. 
  

   lintneri, 
  in 
  which 
  it 
  generally 
  extends 
  only 
  from 
  the 
  costal 
  to 
  the 
  

   subcostal) 
  ,• 
  colors 
  often 
  metallic 
  blue 
  or 
  green 
  on 
  thorax 
  and 
  abdomen 
  

  

  Cordulinae 
  p. 
  484 
  

  

  hi) 
  The 
  sectors 
  of 
  the 
  arculus 
  in 
  close 
  apposition 
  or 
  completely 
  fused 
  for 
  a 
  little 
  

  

  way 
  beyond 
  the 
  arculus; 
  anal 
  loop 
  generally 
  distinctly 
  foot-shaped, 
  with 
  

  

  well 
  developed 
  *'toe"; 
  the 
  last 
  antenodal 
  cross 
  vein 
  often 
  discontinuous 
  

  

  at 
  the 
  subcostal 
  vein 
  Libel 
  lulinae 
  p. 
  506 
  

  

  a, 
  Head 
  with 
  a 
  prominent 
  pyramidal 
  frontal 
  horn; 
  abdomen 
  flat, 
  and 
  almost 
  

   circular 
  in 
  outline 
  as 
  seen 
  from 
  above 
  ; 
  legs 
  long, 
  giving 
  a 
  spiderlike 
  

   aspect 
  to 
  these 
  big 
  nymphs; 
  10th 
  abdominal 
  segment 
  well 
  exposed, 
  not 
  

   telescoped 
  in 
  the 
  apex 
  of 
  the 
  ninth 
  segment; 
  teeth 
  on 
  the 
  lateral 
  lobes 
  of 
  

  

  the 
  labium 
  with 
  deep 
  incisions 
  between 
  them 
  Macromiinae 
  

  

  aa 
  Head 
  without 
  pyramidal 
  frontal 
  horn 
  ; 
  abdomen 
  less 
  flattened, 
  more 
  elongate 
  ; 
  

   teeth 
  on 
  the 
  lateral 
  lobes 
  of 
  the 
  labium 
  much 
  wider 
  than 
  high. 
  

  

  h 
  Lateral 
  appendages 
  of 
  the 
  abdomen 
  more 
  than 
  half 
  as 
  long 
  as 
  the 
  inferiors 
  ; 
  

   hind 
  femora 
  longer 
  than 
  the 
  head 
  is 
  wide; 
  when 
  the 
  lateral 
  spines 
  are 
  

   long 
  (fig. 
  19s), 
  then 
  there 
  is 
  a 
  fall 
  series 
  of 
  big, 
  cultriform 
  dorsal 
  hooks 
  on 
  

  

  the 
  abdomen 
  . 
  Cordulinae 
  

  

  l)h 
  Lateral 
  abdominal 
  appendages 
  generally 
  less 
  than 
  half 
  the 
  length 
  of 
  the 
  

   inferiors 
  ; 
  hind 
  femora 
  generally 
  as 
  long 
  as 
  the 
  head 
  is 
  wide 
  ; 
  often 
  when 
  

   the 
  lateral 
  spines 
  of 
  the 
  abdomen 
  are 
  long 
  the 
  dorsal 
  hooks 
  are 
  wanting 
  or 
  

   reduced 
  Libellulinae 
  

  

  Subfamily 
  ^^acir.owliinae> 
  

  

  A 
  small 
  group 
  of 
  large 
  species, 
  more 
  distinct 
  than 
  any 
  other 
  group 
  

   within 
  the 
  family. 
  The 
  imagos 
  are 
  bulky 
  and 
  not 
  very 
  graceful, 
  hairy 
  

   and 
  not 
  strikingly 
  beautiful 
  in 
  their 
  coloration, 
  but 
  their 
  flight 
  is 
  strong 
  

   and 
  well 
  sustained 
  : 
  they 
  glide 
  through 
  the 
  air 
  with 
  the 
  fearless 
  abandon 
  

   of 
  masters 
  of 
  a 
  situation. 
  

  

  The 
  nymphs 
  are 
  quite 
  unique 
  in 
  the 
  family 
  in 
  the 
  possession 
  of 
  a 
  flat 
  

   abdomen, 
  almost 
  circular 
  in 
  outline, 
  recalling 
  that 
  of 
  Hagenius, 
  

   though 
  less 
  flat 
  and 
  circular 
  than 
  that, 
  and 
  an 
  erect 
  pyramidal 
  horn 
  on 
  

   the 
  front 
  of 
  the 
  head 
  ; 
  in 
  this 
  last 
  character, 
  they 
  are 
  unique 
  among 
  all 
  

   Odonata. 
  They 
  lie 
  flat 
  on 
  the 
  bottom 
  where 
  there 
  is 
  Httle 
  mud, 
  or 
  

   oftener, 
  on 
  some 
  nearly 
  bare 
  ledge 
  in 
  the 
  border 
  of 
  a 
  stream, 
  with 
  their 
  

   thin 
  legs 
  radiately 
  arranged, 
  and 
  the 
  body 
  almost 
  completely 
  covered 
  

   with 
  silt. 
  Thus 
  they 
  await 
  their 
  prey 
  and 
  seize 
  it 
  when 
  it 
  approaches.^ 
  

   They 
  are 
  all 
  an 
  undetermined 
  number 
  of 
  years 
  reaching 
  maturity. 
  

   , 
  Our 
  two 
  genera 
  may 
  be 
  separated 
  as 
  follows 
  : 
  

  

  