﻿96 
  

  

  The 
  author 
  is 
  not 
  in 
  favour 
  of 
  destroying 
  the 
  nymphs 
  by 
  ramming, 
  

   but 
  highly 
  approves 
  of 
  early 
  broods 
  being 
  collected 
  by 
  hand. 
  The 
  

   crushing 
  of 
  adults 
  of 
  early 
  broods 
  in 
  young 
  cane 
  by 
  squeezing 
  the 
  leaf 
  

   sheaths 
  where 
  they 
  congregate 
  is 
  also 
  recommended. 
  Possibly 
  this 
  

   plan 
  would 
  be 
  even 
  more 
  effective 
  than 
  using 
  the 
  kerosene-lysol 
  

   emulsion, 
  but 
  every 
  efficient 
  method 
  should 
  be 
  used 
  against 
  the 
  early 
  

   broods, 
  because 
  it 
  is 
  impossible 
  to 
  do 
  much 
  against 
  the 
  enormous 
  later 
  

   ones. 
  All 
  abandoned 
  land 
  and 
  grass 
  fields 
  near 
  cane 
  should 
  be 
  grazed 
  

   or 
  put 
  under 
  cover 
  crops. 
  The 
  cattle 
  disturb 
  the 
  froghopper 
  so 
  much, 
  

   that 
  it 
  avoids 
  these 
  fields. 
  Cutting 
  the 
  grass 
  is 
  useless. 
  Regarding 
  

   cane-trash, 
  the 
  author 
  now 
  thinks 
  it 
  probable 
  that 
  (where 
  trash 
  cannot 
  

   be 
  removed 
  to 
  the 
  cattle 
  pens) 
  the 
  best 
  plan 
  would 
  be 
  to 
  keep 
  it 
  in 
  a 
  

   few 
  large 
  piles 
  (boucans), 
  rather 
  than 
  long 
  beds 
  between 
  the 
  rows 
  of 
  

   cane, 
  provided 
  that 
  these 
  boucans 
  could 
  be 
  turned 
  right 
  over, 
  and 
  the 
  

   nymphs 
  below 
  destroyed. 
  As 
  regards 
  the 
  destruction 
  of 
  adult 
  frog- 
  

   hoppers, 
  trap 
  lights 
  are 
  about 
  the 
  only 
  method 
  at 
  present 
  of 
  any 
  value 
  

   at 
  all, 
  when 
  the 
  insects 
  appear 
  in 
  great 
  swarms. 
  The 
  following 
  catches 
  

   were 
  made 
  on 
  badly 
  "blighted" 
  fields 
  during 
  September 
  1913: 
  

   Night 
  of 
  5th 
  September, 
  24 
  lamps, 
  56,900 
  froghoppers 
  ; 
  10th 
  Septem- 
  

   ber, 
  12 
  lamps, 
  23,420 
  ; 
  21st 
  September, 
  72 
  lamps, 
  58,363. 
  These 
  were 
  

   only 
  the 
  largest 
  of 
  many 
  catches 
  at 
  fights. 
  The 
  hurricane 
  lamps 
  were 
  

   placed 
  about 
  20 
  to 
  25 
  feet 
  apart, 
  i.e., 
  one 
  opposite 
  the 
  end 
  of 
  each 
  

   cane 
  bed 
  along 
  the 
  trace, 
  and 
  stood 
  in 
  trays 
  about 
  2 
  feet 
  square, 
  with 
  

   a 
  ledge 
  to 
  retain 
  the 
  water 
  and 
  film 
  of 
  kerosene, 
  or 
  a 
  mess 
  of 
  molasses. 
  

   They 
  should 
  also 
  be 
  placed 
  where 
  there 
  is 
  any 
  open 
  space 
  among 
  the 
  

   canes. 
  

  

  Summarised 
  briefly, 
  the 
  author's 
  recommendations 
  are 
  : 
  — 
  (1) 
  That 
  

   a 
  search 
  be 
  made 
  for 
  an 
  efficient 
  egg- 
  or 
  adult-parasite 
  of 
  the 
  frog- 
  

   hopper, 
  though 
  it 
  is 
  very 
  unlikely 
  that 
  any 
  will 
  be 
  procured 
  in 
  islands 
  

   near 
  Trinidad, 
  or 
  any 
  adjacent 
  part 
  of 
  the 
  mainland 
  ; 
  (2) 
  that 
  mean- 
  

   while 
  every 
  effort 
  should 
  be 
  made 
  to 
  get 
  the 
  Syrphid 
  on 
  the 
  early 
  

   broods 
  of 
  froghopper 
  ; 
  (3) 
  abandoned 
  lands 
  adjacent 
  to 
  cane-fields 
  to 
  

   be 
  either 
  put 
  under 
  a 
  cover 
  crop 
  or 
  grazed 
  ; 
  grass 
  " 
  traces 
  " 
  to 
  be 
  hoed 
  

   and 
  the 
  rubbish 
  taken 
  to 
  the 
  cattle 
  pens, 
  especially 
  just 
  before 
  the 
  

   wet 
  season 
  ; 
  (4) 
  all 
  trash 
  should 
  be 
  removed 
  to 
  the 
  pens, 
  and 
  not 
  

   returned 
  to 
  the 
  fields 
  till 
  well 
  broken 
  up 
  and 
  sodden, 
  and 
  especially 
  

   the 
  trash 
  of 
  the 
  two 
  or 
  three 
  rows 
  of 
  cane 
  nearest 
  to 
  traces 
  or 
  grass 
  land 
  

   just 
  before 
  the 
  wet 
  season 
  ; 
  (5) 
  after 
  the 
  appearance 
  of 
  early 
  broods 
  

   of 
  froghopper 
  nymphs 
  they 
  should 
  be 
  destroyed 
  by 
  kerosene-lysol 
  

   emulsion 
  or 
  by 
  squeezing 
  the 
  leaf-sheaths, 
  whichever 
  proves 
  the 
  quicker 
  

   and 
  more 
  effective 
  ; 
  (6) 
  the 
  later 
  large 
  swarms 
  of 
  adults 
  should 
  be 
  

   destroyed 
  as 
  far 
  as 
  possible 
  by 
  trap-lights. 
  

  

  A 
  grasshopper 
  (Xiphidium 
  sp.) 
  is 
  very 
  common 
  in 
  grass 
  lands, 
  and 
  

   destroys 
  froghoppers 
  along 
  with 
  other 
  insects. 
  It 
  is 
  considered 
  to 
  be 
  

   X. 
  varipenne. 
  Next 
  to 
  the 
  Syrphid, 
  however, 
  the 
  author 
  holds 
  spiders 
  

   to 
  be 
  the 
  most 
  effective 
  natural 
  enemies 
  of 
  the 
  froghopper. 
  

  

  GuppY 
  (P. 
  L.). 
  Life-history 
  of 
  the 
  Syrphid 
  fly 
  predaceous 
  on 
  Frog- 
  

   hopper 
  Nymphs. 
  — 
  Bull. 
  Dept. 
  Agric, 
  Trinidad 
  and 
  Tobago, 
  xii, 
  

   no. 
  75, 
  Nov. 
  1913, 
  pp. 
  159-161. 
  

  

  From 
  30 
  to 
  40 
  nymphs 
  are 
  killed 
  and 
  sucked 
  during 
  the 
  life 
  of 
  a 
  

   larva 
  of 
  this 
  fly 
  [Salpingogaster 
  nigra, 
  Schiner], 
  which 
  is 
  from 
  nine 
  to 
  

  

  