﻿DEVELOPMENT 
  OF 
  CALOPTENUS 
  ATLANIS. 
  '273 
  

  

  place 
  at 
  the 
  same 
  time 
  and 
  in 
  the 
  same 
  way, 
  the 
  fore 
  and 
  hind 
  gut 
  

   forming 
  first 
  and 
  simultaneously, 
  by 
  an 
  invagination 
  of 
  the 
  outer 
  germ- 
  

   layer 
  {ectoderm 
  or 
  ectohlast) 
  while 
  the 
  cells 
  of 
  the 
  mid-gut, 
  as 
  Dohrn 
  

   states, 
  arise 
  directly 
  from 
  the 
  yolk. 
  The 
  resorption 
  of 
  the 
  food 
  goes 
  

   on 
  in 
  the 
  mid-gut, 
  the 
  results 
  of 
  digestion 
  passing 
  through 
  the 
  walls 
  

   of 
  this 
  part 
  of 
  the 
  intestinal 
  tract 
  to 
  mix 
  with 
  the 
  circulatory 
  fluid 
  

   or 
  blood. 
  On 
  the 
  other 
  hand, 
  the 
  function 
  of 
  the 
  hind 
  gut 
  is 
  that 
  of 
  an 
  

   urinary 
  bladder, 
  since 
  the 
  Malpighian 
  vessels 
  open 
  into 
  it. 
  Dohrn 
  con- 
  

   firms 
  BUtschli's 
  observations 
  made 
  on 
  the 
  embryo 
  of 
  the 
  honey 
  bee, 
  that 
  

   the 
  urinary 
  or 
  Malpighian 
  vessels 
  arise 
  from 
  the 
  outer 
  germ-layer. 
  Like 
  

   the 
  Malpighian 
  tubes, 
  the 
  salivary 
  glands 
  and 
  the 
  tracheae 
  are 
  offshoots 
  

   of 
  the 
  ectoblast, 
  as 
  shown 
  by 
  Butschli. 
  Likewise, 
  as 
  shown 
  by 
  Ganiu, 
  

   Dohrn 
  claims 
  that 
  the 
  ovaries 
  arise 
  from 
  the 
  hind 
  gut, 
  which 
  it 
  will 
  be 
  

   remembered 
  is 
  an 
  invaginated 
  portion 
  of 
  the 
  ectoblast. 
  

  

  For 
  the 
  cutting 
  and 
  mounting 
  of 
  the 
  sections 
  of 
  locust 
  eggs 
  which 
  I 
  

   studied, 
  I 
  am 
  indebted 
  to 
  Mr. 
  Norman 
  K. 
  Mason, 
  of 
  Providence, 
  R. 
  I. 
  

  

  I. 
  Development 
  of 
  Caloptenus 
  atlanis. 
  

  

  The 
  earliest 
  stage 
  observed 
  was 
  in 
  a 
  mass 
  of 
  eggs 
  of 
  Caloptenus 
  atlanis 
  

   Eiley, 
  which 
  were 
  sent 
  me 
  from 
  Missouri 
  by 
  Prof. 
  O. 
  Y. 
  Riley, 
  with 
  the 
  

   label 
  "eggs 
  of 
  G. 
  atlanis^ 
  laid 
  10 
  days." 
  These 
  eggs 
  were 
  laid 
  in 
  the 
  

   autumn, 
  and 
  the 
  embryos, 
  as 
  seen 
  by 
  the 
  following 
  account, 
  were 
  already 
  

   far 
  advanced, 
  the 
  body-segments 
  and 
  appendages 
  having 
  appeared, 
  the 
  

   eyes 
  being 
  indicated, 
  the 
  brain 
  and 
  nervous 
  cord 
  being 
  well 
  formed, 
  and 
  

   the 
  oesophagus 
  and 
  crop 
  (stomodaeum) 
  and 
  hind 
  gut 
  (proctodaeum) 
  being 
  

   indicated, 
  so 
  that 
  the 
  embryos 
  had 
  probably 
  nearly 
  reached 
  the 
  stage 
  

   represented 
  by 
  PI. 
  XVI, 
  Fig, 
  1, 
  of 
  G. 
  spretus. 
  

  

  This 
  shows 
  that 
  development 
  in 
  the 
  eggs 
  of 
  those 
  locusts 
  which 
  deposit 
  

   their 
  eggs 
  in 
  the 
  autumn 
  goes 
  on 
  rapidly, 
  and 
  that 
  the 
  embryo 
  is 
  nearly 
  

   perfectly 
  formed 
  and 
  about 
  ready 
  to 
  hatch 
  in 
  the 
  early 
  autumn. 
  As 
  is 
  

   well 
  known, 
  some 
  locusts 
  {G. 
  spretus) 
  do 
  hatch 
  in 
  the 
  late 
  autumn 
  in 
  mild 
  

   weather, 
  while 
  the 
  rule 
  is 
  that 
  the 
  young 
  hatch 
  out 
  in 
  March 
  and 
  Aijril. 
  

   At 
  all 
  events, 
  it 
  is 
  proved 
  by 
  finding 
  the 
  embryos 
  so 
  far 
  advanced 
  ten 
  

   days 
  after 
  oviposition, 
  that 
  development 
  begins 
  as 
  soon 
  as 
  the 
  eggs 
  are 
  

   deposited, 
  and 
  that 
  the 
  embryo 
  is 
  nearly 
  perfected 
  atid 
  about 
  ready 
  to 
  

   hatch, 
  until 
  the 
  approach 
  of 
  winter 
  arrests 
  the 
  final 
  stages 
  of 
  develop- 
  

   ment 
  of 
  the 
  embryo, 
  a 
  few 
  warm 
  days 
  in 
  spring 
  enabling 
  it 
  to 
  complete 
  

   its 
  growth 
  and 
  to 
  hatch. 
  

  

  The 
  drawings 
  on 
  Plates 
  XX 
  and 
  XXI 
  represent 
  the 
  earliest 
  observed 
  

   stages 
  of 
  Galoptenus 
  atlanis 
  ; 
  it 
  having 
  been 
  impossible 
  to 
  obtain 
  the 
  

   freshly-laid 
  eggs 
  of 
  Caloptenus 
  spretus 
  within 
  the 
  last 
  two 
  or 
  three 
  years, 
  

   owing 
  to 
  the 
  general 
  scarcity 
  of 
  the 
  locust 
  and 
  of 
  local 
  observers 
  who 
  

   could 
  collect 
  them. 
  To 
  observe 
  any 
  earlier 
  stages 
  than 
  those 
  figured 
  

   it 
  would 
  be 
  necessary 
  to 
  secure 
  the 
  eggs 
  as 
  soon 
  as 
  laid, 
  and 
  then 
  to 
  

   place 
  examjiles 
  of 
  them 
  in 
  alcohol 
  or 
  in 
  hardening 
  fluid, 
  according 
  to 
  

   18 
  E 
  

  

  