﻿20 
  

  

  action 
  of 
  the 
  parts, 
  this 
  connecting 
  memhrane 
  is 
  siippHed 
  with 
  

   certain 
  highly 
  chitinized 
  portions 
  which 
  act 
  presumably 
  as 
  

   ■'braces" 
  or 
  "connecting 
  rods." 
  The 
  parts, 
  as 
  a 
  whole, 
  are 
  very 
  

   strong, 
  being 
  highly 
  chitinized 
  throughout. 
  So 
  much 
  so, 
  in 
  fact, 
  

   that 
  it 
  was 
  found 
  necessary 
  to 
  first 
  boil 
  them 
  in 
  caustic 
  potash 
  

   (5 
  per 
  cent, 
  solution) 
  before 
  attempting 
  to 
  study 
  them. 
  

  

  The 
  position 
  of 
  the 
  mouth-parts 
  on 
  the 
  head 
  is 
  ventral. 
  The 
  

   clypeus 
  extends 
  out 
  over 
  the 
  parts 
  with 
  the 
  exception 
  of 
  the 
  

   mandibles, 
  which 
  fold 
  together 
  directly 
  in 
  front, 
  and 
  the 
  distal 
  

   ends 
  of 
  the 
  maxilary 
  palpi 
  and 
  the 
  labrum-epipharynx. 
  

  

  That 
  the 
  parts 
  do 
  represent 
  a 
  generalized 
  type 
  may 
  be 
  seen 
  bv 
  

   looking 
  at 
  those 
  of 
  Lyda 
  sp. 
  (Plate 
  I, 
  figure 
  i.) 
  The 
  parts 
  are 
  

   drawn 
  in 
  situ 
  to 
  give 
  an 
  idea 
  of 
  the 
  comparative 
  size 
  of 
  the 
  dif- 
  

   ferent 
  parts 
  and 
  their 
  position 
  in 
  relation 
  to 
  each 
  other. 
  We 
  have 
  

   here 
  mandibles 
  {nid), 
  strong, 
  highly 
  chitinous, 
  large 
  in 
  compari- 
  

   son 
  to 
  the 
  other 
  parts 
  and 
  acting 
  independently. 
  The 
  view 
  is 
  

   ventral 
  and 
  the 
  labium 
  (U) 
  is 
  seen 
  overlying 
  the 
  other 
  parts. 
  The 
  

   mentum 
  {m) 
  is 
  shield 
  shape, 
  the 
  lateral 
  edges 
  being 
  bent 
  inward 
  

   like 
  the 
  sides 
  of 
  a 
  saddle. 
  From 
  the 
  mentum 
  extend 
  distad 
  the 
  

   glossa 
  {gl) 
  and 
  the 
  paraglossa 
  ( 
  pgl). 
  Caudad 
  of 
  the 
  mentum 
  and 
  

   lying 
  in 
  the 
  connecting 
  tissue 
  is 
  a 
  portion 
  that 
  is 
  chitinized 
  and 
  

   supplied 
  with 
  hairs. 
  Until 
  further 
  studies 
  of 
  higher 
  orders 
  are 
  

   made 
  this 
  part 
  will 
  be 
  called 
  the 
  sub-mentum 
  {sm), 
  since 
  in 
  go- 
  

   ing 
  from 
  the 
  lower 
  to 
  the 
  higher 
  forms 
  this 
  structure 
  becomes 
  

   more 
  and 
  more 
  important 
  and 
  is 
  in 
  the 
  family 
  Apidae 
  distinctly 
  

   joined 
  to 
  the 
  mentum. 
  The 
  tendency, 
  however, 
  is 
  shown 
  within 
  

   the 
  family 
  Tcnthrcdinidac. 
  From 
  the 
  base 
  of 
  the 
  paraglossa 
  

   extend 
  laterad 
  on 
  either 
  side 
  the 
  labial 
  palpi 
  {Up). 
  They 
  are 
  four 
  

   lobed. 
  There 
  is 
  an 
  hypopharynx 
  but 
  it 
  is 
  not 
  distinct 
  in 
  some 
  

   species. 
  It 
  is 
  well 
  shown 
  in 
  drawings 
  farther 
  on. 
  

  

  Right 
  and 
  left 
  of 
  the 
  labium 
  lie 
  the 
  maxillae 
  {inx'). 
  One 
  of 
  

   another 
  species 
  can 
  be 
  seen 
  dissected 
  out 
  in 
  Plate 
  II, 
  fixgure 
  4. 
  

   This 
  figure 
  will 
  serve 
  equally 
  well 
  in 
  describing 
  the 
  parts. 
  This 
  

   is 
  figured 
  for 
  the 
  reason 
  that 
  in 
  Lyda 
  sp. 
  the 
  cardo 
  {cd) 
  is 
  not 
  

   visible 
  since 
  it 
  forms 
  with 
  the 
  stipes 
  {st) 
  a 
  right 
  angle. 
  The 
  

   maxillae 
  are 
  not 
  unlike 
  the 
  general 
  type, 
  that 
  is, 
  the 
  cardo, 
  stipes, 
  

   galea, 
  and 
  lacinia 
  are 
  easily 
  understandable. 
  The 
  stipes, 
  as 
  is 
  

   also 
  the 
  mentum 
  of 
  the 
  labium, 
  is 
  very 
  much 
  arched, 
  making 
  it 
  

   difficult 
  to 
  show 
  the 
  true 
  form 
  by 
  drawing 
  one 
  aspect. 
  

  

  