﻿CHALCIDOID 
  PAKASITES 
  OF 
  PSYLLIDS. 
  55 
  

  

  Head 
  (8:5). 
  Antenna 
  (fig. 
  6, 
  a, 
  a') 
  0-87 
  mm. 
  ; 
  scape 
  (15:4) 
  longer 
  (5:2) 
  

   than 
  the 
  pedicel 
  (2 
  : 
  1) 
  and 
  only 
  three-fourths 
  as 
  long 
  as 
  the 
  club, 
  excluding 
  the 
  spur 
  ; 
  

   the 
  second 
  funicular 
  joint 
  five-sixths 
  of 
  the 
  third. 
  The 
  longest 
  bristles 
  on 
  the 
  first 
  

   funicular 
  extend 
  well 
  on 
  to 
  the 
  first 
  segment 
  of 
  the 
  club, 
  whereas 
  in 
  T. 
  radiatus 
  they 
  

   do 
  not 
  pass 
  the 
  end 
  of 
  the 
  funicle. 
  The 
  funicular 
  and 
  club 
  segments 
  are 
  also 
  both 
  

   absolutely 
  longer 
  and 
  narrower 
  than 
  in 
  the 
  Indian 
  species. 
  The 
  longest 
  ventral 
  

   bristle 
  of 
  the 
  first 
  club 
  segment 
  is 
  four-fifths 
  of 
  the 
  club, 
  including 
  the 
  spur. 
  

  

  Thorax. 
  Pronotum 
  with 
  the 
  posterior 
  row 
  only 
  of 
  eight 
  (4, 
  4) 
  bristles, 
  including 
  

   the 
  spiracular 
  bristles. 
  Propodeon 
  with 
  the 
  median 
  keel 
  narrow 
  ; 
  on 
  the 
  inner 
  

   (admedian) 
  side 
  of 
  the 
  spiracle 
  and 
  at 
  less 
  than 
  its 
  transverse 
  diameter 
  from 
  the 
  

   spiracle, 
  a 
  short 
  curved 
  keel 
  runs 
  backwards 
  to 
  beyond 
  middle 
  ; 
  a 
  similar 
  ridge 
  starting 
  

   from 
  the 
  posterior 
  edge 
  halfway 
  between 
  the 
  mid 
  keel 
  and 
  the 
  hind 
  coxae, 
  runs 
  

   forward 
  to 
  beyond 
  middle 
  and 
  parallel 
  for 
  a 
  short 
  distance 
  with 
  the 
  former. 
  Whole 
  

   surface 
  of 
  propodeon 
  more 
  irregular. 
  Spiracle 
  set 
  well 
  forward, 
  not 
  more 
  than 
  

   one-third 
  its 
  own 
  length 
  from 
  the 
  anterior 
  edge 
  of 
  the 
  sulcus, 
  and 
  actually 
  touching 
  

   the 
  posterior 
  one. 
  

  

  Wings. 
  Fore 
  wings, 
  length, 
  1 
  • 
  1 
  mm. 
  The 
  marginal 
  vein 
  narrow 
  ; 
  4-5 
  bristles 
  

   on 
  radius, 
  longest 
  marginal 
  cilia 
  one-seventh 
  the 
  width. 
  Hind 
  wings, 
  0-9 
  mm. 
  ; 
  

   no 
  cilia 
  as 
  long 
  as 
  the 
  width. 
  

  

  Legs 
  : 
  tarsal 
  proportions 
  :— 
  (i) 
  15, 
  24, 
  23, 
  30 
  ; 
  (ii), 
  20, 
  25, 
  24, 
  30 
  ; 
  (iii), 
  20, 
  25, 
  

   24, 
  30. 
  

  

  Abdomen 
  with 
  four 
  bristles 
  between 
  the 
  stylets. 
  

  

  Length, 
  about 
  1-3 
  mm. 
  ; 
  alar 
  expanse, 
  2-6 
  mm. 
  

  

  Type 
  <$ 
  in 
  the 
  British 
  Museum. 
  

  

  Bred 
  from 
  Trioza 
  citri, 
  Laing, 
  attacking 
  Citrus. 
  

  

  Kenya 
  Colony 
  : 
  Kabete, 
  1920. 
  (F. 
  W. 
  Dry). 
  

  

  T. 
  dryi 
  is 
  unlike 
  any 
  other 
  African 
  Tetrastichus 
  with 
  which 
  I 
  am 
  acquainted, 
  

   except 
  T. 
  macidifer, 
  Silv. 
  I 
  desire 
  to 
  thank 
  Prof. 
  Silvestri 
  very 
  heartily 
  for 
  an 
  

   opportunity 
  of 
  examining 
  the 
  type 
  of 
  his 
  species. 
  The 
  following 
  comparative 
  notes 
  

   may 
  be 
  given 
  : 
  — 
  

  

  In 
  Tetrastichus 
  macidifer, 
  Silv., 
  the 
  scape 
  (about 
  8 
  : 
  3) 
  is 
  barely 
  twice 
  as 
  long 
  as 
  

   the 
  pedicel 
  and 
  about 
  five-sjxths 
  of 
  the 
  club 
  not 
  including 
  the 
  spur 
  (fig. 
  6, 
  c). 
  The 
  

   sense 
  organ 
  is 
  half 
  as 
  long 
  as 
  the 
  greatest 
  breadth, 
  i.e., 
  relatively 
  longer 
  than 
  in 
  T. 
  

   dryi 
  and 
  T. 
  radiatus. 
  There 
  are 
  on 
  the 
  funicular 
  joints 
  and 
  first 
  of 
  the 
  club 
  the 
  

   following 
  tubular 
  hairs 
  : 
  6, 
  4, 
  4, 
  3, 
  1 
  ; 
  no 
  sense-organ 
  on 
  the 
  first 
  funicular 
  and 
  one 
  

   on 
  the 
  other 
  joints 
  and 
  club 
  segments. 
  The 
  longest 
  ventral 
  tubular 
  bristle 
  on 
  the 
  

   first 
  segment 
  of 
  the 
  club 
  is 
  about 
  one-fourth 
  as 
  long 
  again 
  as 
  the 
  club 
  including 
  the 
  

   terminal 
  spur, 
  while 
  the 
  ventral 
  bristle 
  on 
  the 
  second 
  segment 
  is 
  as 
  long 
  as 
  the 
  club 
  

   without 
  the 
  spur. 
  The 
  mandible 
  (fig. 
  6, 
  d) 
  is 
  definitely 
  tridentate. 
  On 
  the 
  mid 
  

   lobe 
  of 
  the 
  mesonotum 
  are 
  two 
  bristles 
  before 
  the 
  suture 
  on 
  the 
  proximal 
  third. 
  

   The 
  spiracle 
  of 
  the 
  propodeon 
  is 
  small, 
  at 
  rather 
  more 
  than 
  its 
  own 
  length 
  from 
  the 
  

   anterior 
  edge, 
  and 
  about 
  one-third 
  as 
  long 
  as 
  the 
  mid 
  keel. 
  In 
  the 
  fore 
  wings 
  the 
  

   longest 
  cilia 
  are 
  two-sevenths 
  of 
  the 
  breadth, 
  in 
  the 
  hind 
  wings 
  nearly 
  half 
  as 
  long 
  

   again 
  as 
  the 
  breadth. 
  Besides 
  the 
  bristles 
  enumerated 
  each 
  segment 
  of 
  the 
  funicle 
  

   bears 
  one 
  (not 
  strictly 
  in 
  the 
  whorl) 
  laterally 
  about 
  or 
  below 
  the 
  middle, 
  and 
  the 
  last 
  

   segment 
  and 
  the 
  club 
  segments 
  have 
  a 
  long 
  ventral 
  bristle 
  as 
  well. 
  

  

  Tetrastichus 
  radiatus, 
  sp. 
  nov. 
  

  

  Similar 
  in 
  colour 
  and 
  structure 
  to 
  T. 
  dryi, 
  sp. 
  n., 
  but 
  differing 
  in 
  possessing 
  

   almost 
  entirely 
  pale 
  legs, 
  the 
  hind 
  femora 
  at 
  most 
  with 
  a 
  trace 
  of 
  infuscation 
  dorsally. 
  

   In 
  the 
  c? 
  the 
  sense-organ 
  also 
  is 
  lower 
  down 
  on 
  the 
  ventral 
  edge 
  of 
  the 
  scape, 
  and 
  the 
  

   antennal 
  proportions 
  generally 
  are 
  different. 
  

  

  