﻿54 
  

  

  CIRCULAR 
  2 
  7 
  0, 
  U. 
  S. 
  DEPARTMENT 
  OF 
  AGRICULTURE 
  

  

  black 
  or 
  gray 
  with 
  red 
  or 
  orange 
  

   markings. 
  Some 
  of 
  them 
  are 
  

   covered 
  with 
  a 
  white 
  waxy 
  secre- 
  

   tion, 
  giA^ing 
  them 
  the 
  appearance 
  

   of 
  mealybugs. 
  Although 
  most 
  

   lad^'beetles 
  are 
  conspicuous, 
  they 
  

   are 
  not 
  molested 
  by 
  birds, 
  possibh^ 
  

   because 
  they 
  have 
  a 
  disagreeable 
  

   taste. 
  

  

  The 
  larvae 
  of 
  syrphid 
  flies 
  are 
  

   common 
  enemies 
  of 
  aphids 
  and 
  are 
  

   most 
  often 
  found 
  in 
  colonies 
  of 
  the 
  

   woolly 
  aphid. 
  Frequently 
  they 
  

   destro}^ 
  the 
  colonies 
  entirely. 
  

   These 
  larvae, 
  or 
  maggots, 
  (fig. 
  66) 
  

  

  >>AT, 
  

  

  M 
  

  

  '\K 
  

  

  ^ 
  C 
  

  

  

  

  JPigure 
  66. 
  — 
  Larva 
  of 
  a 
  syrphid 
  fly. 
  

   Enlarged. 
  

  

  are 
  nearly 
  one-half 
  inch 
  long 
  when 
  

   full-grown, 
  3^ellowish 
  or 
  grayish, 
  

   and 
  often 
  with 
  a 
  stripe 
  down 
  the 
  

   back. 
  The 
  body 
  is 
  widest 
  behind, 
  

   and 
  the 
  narrow 
  head 
  is 
  restlessly 
  

   moved 
  about 
  as 
  the 
  maggot 
  

   searches 
  for 
  food. 
  No 
  legs 
  are 
  evi- 
  

   dent. 
  The 
  adult 
  syrphid 
  flies 
  ( 
  fig. 
  

   67) 
  are 
  usually 
  black, 
  striped 
  with 
  

  

  yellow, 
  and 
  may 
  be 
  mistaken 
  for 
  

   wasps 
  or 
  bees. 
  They 
  fly 
  and 
  often 
  

   poise 
  in 
  midair 
  before 
  

  

  darting 
  

  

  Figure 
  67. 
  — 
  Syrphid 
  fly. 
  

  

  down 
  to 
  a 
  colony 
  of 
  aphids 
  to 
  de- 
  

   posit 
  their 
  eggs. 
  The 
  eggs 
  are 
  

   elongated, 
  dirty 
  whitish, 
  and 
  are 
  

   laid 
  singly 
  among 
  the 
  aphids. 
  

  

  Figure 
  68.— 
  -Young 
  of 
  a 
  lacewing 
  fly. 
  

   Enlarged. 
  

  

  The 
  young 
  of 
  lacewing 
  flies 
  (fig. 
  

   68) 
  are 
  effective 
  enemies 
  of 
  aphids, 
  

   and 
  also 
  feed 
  on 
  other 
  insects, 
  such 
  

   as 
  orchard 
  mites, 
  newly 
  hatched 
  

  

  