﻿i 
  

  

  189O.J 
  BOTANICAJ. 
  GAZETTE. 
  I99 
  

  

  ft 
  

  

  Flowers 
  and 
  insects. 
  V 
  

  

  CHARLES 
  ROBERTSON. 
  

  

  Astragalus 
  Mexicanus 
  A. 
  DC. 
  — 
  The 
  flowers 
  are 
  cream- 
  

   color, 
  often'v^'ith 
  a 
  bluish 
  tinge 
  at 
  the 
  tip 
  of 
  the 
  keel. 
  Tiie 
  

   Avings 
  and 
  keel 
  are 
  closely 
  fastened 
  together, 
  so 
  that 
  they 
  

   must 
  be 
  depressed 
  simultaneously. 
  The 
  rigid 
  banner 
  is 
  fold- 
  

   ed 
  over 
  the 
  wings 
  and 
  keel, 
  and" 
  projects 
  straight 
  forward 
  in 
  

   front 
  of 
  the 
  calyx 
  tube. 
  This 
  tube 
  measures 
  about 
  8 
  mm., 
  

   and 
  the 
  parts 
  of 
  the 
  flower 
  are 
  so 
  contracted 
  beyond 
  it 
  that 
  

   after 
  a 
  bee 
  has 
  forced 
  its 
  head 
  in 
  so 
  as 
  to 
  touch 
  the 
  anthers, 
  

   it 
  still 
  needs 
  a 
  proboscis 
  lo 
  to 
  13 
  mm. 
  long 
  to 
  obtain 
  the 
  sweets. 
  

   The 
  petals 
  are 
  thus 
  disposed 
  so 
  as 
  to 
  limit 
  the 
  accessibility 
  

   of 
  the 
  nectar 
  and 
  to 
  restrict 
  the 
  place 
  of 
  pollen-contact 
  to 
  

   the 
  underside 
  of 
  the 
  bee's 
  head. 
  The 
  stigma 
  only 
  slightly 
  

   surpasses 
  the 
  anthers 
  and 
  mav 
  touch 
  the 
  bee 
  a 
  little 
  m 
  ad- 
  

   vance 
  of 
  them, 
  but 
  self-pollination 
  may 
  occur 
  in 
  absence 
  of 
  

  

  nsects. 
  

  

  - 
  *j 
  -v^ 
  ^H- 
  t<j 
  a 
  

  

  The 
  flower 
  is 
  adapted 
  to 
  thelongest-tonguedbees. 
  From 
  

   its 
  early 
  blooming 
  it 
  is 
  especially 
  exposed 
  to 
  Bombus 
  females 
  

   and 
  to 
  species 
  of 
  Synhalonia. 
  On 
  three 
  days, 
  April 
  27, 
  30, 
  

   and 
  May 
  2, 
  I 
  observed 
  the 
  following 
  visitors 
  : 
  

  

  Hymenoptera 
  — 
  A-pidce: 
  (i) 
  Bombus 
  separatus 
  Cr. 
  9 
  , 
  s., 
  

   once; 
  (2) 
  B. 
  americanorum 
  F. 
  9 
  , 
  s. 
  ab. 
  ; 
  (3) 
  B. 
  pennsyl- 
  

   ^'anicus 
  DeG. 
  9 
  , 
  s. 
  ; 
  (4) 
  Synhalonia 
  speciosa 
  Cr. 
  ^9, 
  s., 
  

   ab. 
  ; 
  (5) 
  S. 
  atriventris 
  Sm. 
  9 
  , 
  s. 
  and 
  c. 
  p., 
  very 
  ab. 
  

  

  Four 
  butterflies 
  were 
  seen 
  sucking, 
  viz. 
  : 
  Papiho 
  asterias, 
  

   ^ohas 
  philodice, 
  Nisoniades 
  icelus 
  and 
  N. 
  juvenahs, 
  but 
  they 
  

   are 
  mere 
  intruders, 
  since 
  they 
  steal 
  the 
  honey 
  without 
  forcmg 
  

   "own 
  the 
  keel. 
  

  

  Strofhostyles 
  angulosa 
  Ell. 
  ^— 
  The 
  keel 
  is 
  bent 
  strongly 
  to 
  

   the 
  nglit 
  and 
  curves 
  around 
  so 
  that 
  its 
  tip 
  stands 
  over 
  its 
  

   base. 
  The 
  base 
  is 
  large 
  and 
  .sack-like 
  and 
  is 
  produced 
  

   above 
  into 
  a 
  ridge 
  which 
  opposes 
  the 
  passage 
  to 
  the 
  nectary, 
  

   ^i^e 
  left 
  \^ing 
  is 
  turned 
  to 
  the 
  right, 
  so 
  that 
  the 
  bee 
  is 
  re- 
  

   quired 
  to 
  alight 
  upon 
  the 
  right 
  side, 
  and 
  she 
  enters 
  the 
  flow- 
  

   er 
  between 
  the 
  tip 
  and 
  the 
  basal 
  process 
  oi 
  the 
  keel, 
  ^eiz- 
  

   |ng 
  this 
  process 
  with 
  her 
  front 
  feet, 
  the 
  bee 
  pulls 
  the 
  keel 
  

   downward 
  and 
  backward, 
  whereupon 
  the 
  stigma 
  and 
  tne 
  

   pollen-laden 
  brush 
  of 
  the 
  style 
  sweep 
  out 
  over 
  her 
  thorax, 
  in 
  

   !!l!!J2ili^!!_!i^?"^''^ 
  receives 
  pollen 
  already 
  deposited 
  by 
  an- 
  

  

  • 
  »»7dl^rl""'fu'" 
  *^ 
  -lescribed 
  by 
  Foerste 
  in 
  Am. 
  Nat. 
  XIX, 
  887 
  

   repress 
  the 
  keel 
  in 
  the 
  way 
  described 
  by 
  him. 
  

  

  888 
  

  

  