﻿On 
  some 
  Draff^iifl'es 
  and 
  their 
  Prey. 
  405 
  

  

  greatest 
  width 
  730, 
  distance 
  of 
  tips 
  390, 
  breadth 
  of 
  palm 
  at 
  

   base 
  188. 
  

  

  Named 
  for 
  Dr. 
  R. 
  Houy, 
  Surgeon 
  and 
  Naturalist 
  to 
  the 
  

   German 
  Boundary 
  Expedition, 
  whose 
  untimely 
  death 
  by 
  

   the 
  hand 
  of 
  his 
  native 
  servant 
  we 
  have 
  to 
  deplore. 
  

  

  P.S. 
  — 
  When 
  describing 
  Bubalus 
  caffer 
  adamau(S 
  the 
  

   dimensions 
  of 
  the 
  type 
  skull 
  were 
  omitted 
  by 
  mistake. 
  

   They 
  are 
  given 
  here 
  : 
  — 
  

  

  Basal 
  length 
  411 
  mm. 
  ; 
  palatal 
  length 
  250; 
  postorbital 
  

   width 
  205; 
  mastoid 
  width 
  213; 
  nasals 
  177x63; 
  horns, 
  

   length 
  along 
  outer 
  curve 
  550, 
  greatest 
  width 
  525, 
  distance 
  

   of 
  tips 
  280, 
  breadth 
  of 
  palm 
  at 
  base 
  155. 
  

  

  LVIII. 
  — 
  Some 
  Dragonfl'ies 
  and 
  their 
  Prey. 
  

   By 
  Herbeet 
  Campion. 
  

  

  It 
  is 
  a 
  well-known 
  fact 
  that 
  Odonata, 
  in 
  all 
  their 
  stages, 
  are 
  

   liiglily 
  predaceous 
  creature-^, 
  and 
  are 
  veritable 
  tyrants 
  in 
  tiie 
  

   insect-world. 
  Prey 
  is 
  seized 
  by 
  tlie 
  nymphs 
  with 
  the 
  extra- 
  

   ordinary 
  modification 
  of 
  the 
  labium 
  called 
  the 
  " 
  mask." 
  It 
  

   is 
  customary 
  for 
  imagines, 
  with 
  which 
  we 
  shall 
  deal 
  exclu- 
  

   sively 
  on 
  the 
  present 
  occasion, 
  to 
  take 
  their 
  prey 
  during 
  

   flight, 
  and 
  it 
  may 
  be 
  assumed 
  that 
  they 
  capture 
  the 
  smaller 
  

   insects 
  upon 
  which 
  they 
  feed 
  with 
  the 
  aid 
  alone 
  of 
  their 
  

   powerful 
  jaws. 
  Larger 
  prey, 
  no 
  doubt, 
  is 
  caught 
  and 
  held 
  

   by 
  the 
  Dragonfly's 
  spiny 
  legs, 
  the 
  length 
  and 
  position 
  of 
  

   which 
  are 
  such 
  as 
  to 
  enable 
  their 
  possessor 
  to 
  bring 
  all 
  of 
  

   them 
  simultaneously 
  to 
  the 
  level 
  of 
  the 
  mouth. 
  

  

  The 
  capacity 
  for 
  destiuction 
  possessed 
  by 
  Dragonflies 
  is 
  

   enormous, 
  and 
  " 
  Beutennuiller 
  found 
  that 
  one 
  of 
  the 
  large 
  

   ones 
  would 
  eat 
  forty 
  house-flies 
  inside 
  of 
  two 
  hours, 
  while 
  a 
  

   smaller 
  one 
  ate 
  twenty-five 
  in 
  the 
  same 
  time 
  " 
  (Dr. 
  L. 
  O. 
  

   Howard, 
  ' 
  The 
  Insect 
  Book,' 
  1902, 
  p. 
  365). 
  On 
  the 
  other 
  

   hand, 
  their 
  power 
  of 
  resisting 
  famine 
  is 
  considerable, 
  and 
  

   during 
  dull 
  weather, 
  when 
  they 
  fly 
  very 
  rarely, 
  if 
  at 
  all, 
  

   they 
  probably 
  pass 
  several 
  days 
  in 
  succession 
  without 
  

   obtaining 
  any 
  food 
  whatever. 
  In 
  those 
  countries, 
  therefore, 
  

   where 
  the 
  sun 
  shines 
  without 
  intermission 
  for 
  lung 
  periods 
  

   at 
  a 
  time, 
  the 
  activity 
  of 
  Dragonflies 
  must 
  be 
  much 
  greater 
  

   than 
  in 
  cloudy 
  climates, 
  and 
  the 
  consumption 
  of 
  other 
  insects 
  

   must 
  increase 
  in 
  a 
  corresponding 
  degree. 
  

  

  The 
  principal 
  source 
  of 
  our 
  knowledge 
  of 
  what 
  Dragoiiflies 
  

  

  