﻿258 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  • 
  

  

  oval, 
  with 
  irregular 
  broad 
  thickened 
  patches. 
  Beneath, 
  on 
  the 
  segments 
  

   behind 
  the 
  4th 
  the 
  callosities 
  disappear, 
  but 
  there 
  are 
  raised 
  smooth 
  

   oval 
  areas. 
  A 
  pair 
  of 
  thoracic 
  feet 
  on 
  each 
  of 
  the 
  three 
  segments 
  5 
  

   they 
  are 
  3-jointed, 
  basal 
  joint 
  membranous; 
  2d 
  joint 
  about 
  three-fourths 
  

   as 
  long 
  as 
  wide; 
  3d 
  joint 
  about 
  two-thirds 
  as 
  wide 
  as 
  the 
  2d, 
  and 
  slightly 
  

   longer. 
  The 
  9th 
  abdominal 
  segment 
  but 
  little 
  narrower 
  than 
  the 
  

   8th; 
  the 
  10th 
  about 
  one-third 
  as 
  wide 
  as 
  the 
  9th. 
  A 
  pair 
  of 
  meso- 
  

   thoracic 
  spiracles, 
  and 
  eight 
  abdominal 
  pairs. 
  

  

  Head 
  not 
  quite 
  so 
  large 
  in 
  proportion 
  as 
  in 
  X 
  colonus. 
  Labrum 
  small, 
  

   not 
  quite 
  so 
  broad 
  as 
  in 
  X. 
  colonus^ 
  convex 
  and 
  well 
  rounded 
  in 
  front, 
  

   and 
  very 
  hairy. 
  Mandibles 
  black. 
  

  

  Antennae 
  4-jointed, 
  1st 
  joint 
  apparently 
  divided 
  into 
  two 
  subseg- 
  

   ments; 
  3d 
  a 
  little 
  longer 
  and 
  narrower 
  than 
  the 
  2d; 
  the 
  4th 
  minute, 
  

   obtuse, 
  one-half 
  as 
  long 
  as 
  the 
  3d 
  is 
  wide. 
  Maxillae 
  with 
  the 
  lobe 
  

   rather 
  small, 
  reaching 
  to 
  near 
  the 
  end 
  of 
  the 
  3d 
  joint 
  of 
  the 
  palpus. 
  

   Maxillary 
  palpi 
  4-jointed, 
  2d 
  joint 
  slightly 
  shorter 
  and 
  narrower 
  than 
  

   the 
  1st 
  ; 
  4th 
  half 
  as 
  thick 
  as 
  the 
  3d, 
  and 
  pointed 
  at 
  the 
  tip. 
  Labium 
  

   with 
  the 
  mentum 
  nearly 
  square, 
  narrower 
  than 
  the 
  submentum. 
  The 
  

   ligula, 
  which 
  is 
  very 
  small 
  in 
  X. 
  colonus, 
  is 
  here 
  entirely 
  wanting. 
  

   Labial 
  palpi 
  3-jointed; 
  2d 
  joint 
  not 
  so 
  long 
  as 
  wide; 
  3d 
  very 
  long 
  and 
  

   slender, 
  a 
  little 
  longer 
  than 
  the 
  2d 
  and 
  about 
  one-half 
  as 
  thick; 
  they 
  

   reach 
  as 
  far 
  as 
  the 
  end 
  of 
  the 
  3d 
  maxillary 
  palpal 
  joint. 
  

  

  Length, 
  17""°^; 
  breadth 
  of 
  prothoracic 
  segment, 
  5""^; 
  length, 
  2°^™; 
  

   breadth 
  of 
  8th 
  abdominal 
  segmpnt, 
  3.5'"'". 
  

  

  This 
  larva 
  may 
  be 
  recognized 
  by 
  the 
  stout, 
  thick 
  thoracic 
  feet, 
  by 
  the 
  

   rather 
  small 
  prothoracic 
  segment 
  compared 
  with 
  the 
  two 
  hinder 
  ones, 
  

   by 
  the 
  absence 
  of 
  the 
  ligula, 
  by 
  the 
  large 
  well-developed 
  palpi 
  and 
  

   antennse, 
  and 
  by 
  the 
  shape 
  of 
  the 
  callosities. 
  

  

  THE 
  COMMON 
  OAK 
  CLYTUS. 
  

  

  Xylotrechus 
  colonus 
  (Fabr.). 
  PI. 
  XII, 
  Figs. 
  2, 
  2a. 
  

  

  Body 
  of 
  the 
  usual 
  shape, 
  near 
  that 
  of 
  Phymatodes. 
  Pro 
  thorax 
  less 
  

   than 
  one-half 
  as 
  long 
  as 
  wide; 
  disk 
  exactly 
  one-half 
  as 
  long 
  as 
  wide; 
  

   the 
  disk 
  is 
  smooth 
  on 
  the 
  posterior 
  half, 
  irregular 
  on 
  the 
  front 
  edge, 
  

   with 
  a 
  broad 
  irregular 
  median 
  lobe 
  in 
  front; 
  the 
  front 
  edge 
  of 
  this 
  

   smooth 
  space 
  is 
  often 
  tinged 
  with 
  dark. 
  In 
  front 
  of 
  this 
  smooth 
  'area 
  

   is 
  a 
  clear, 
  pale, 
  hairy 
  space, 
  and 
  still 
  beydnd 
  (anteriorly) 
  are 
  two 
  irregu- 
  

   larly 
  oval 
  spaces 
  which 
  are 
  hairy 
  and 
  irregularly 
  spotted, 
  and 
  often 
  

   tinted 
  dark. 
  The 
  under 
  side 
  of 
  the 
  prothoracic 
  segment 
  is 
  quite 
  hairy, 
  

   with 
  minute 
  oval 
  patches 
  among 
  the 
  hairs, 
  and 
  with 
  two 
  conspicuous 
  

   small 
  dark 
  diverging 
  patches 
  on 
  the 
  middle 
  of 
  the 
  segment, 
  but 
  situated 
  

   rather 
  far 
  apart. 
  Mesothoracic 
  segment 
  a 
  little 
  narrower 
  than 
  the 
  

   prothoracic 
  and 
  shorter 
  than 
  the 
  metathoracic 
  segment, 
  the 
  latter 
  a 
  

   little 
  shorter 
  and 
  but 
  very 
  slightly 
  wider 
  than 
  the 
  mesothoracic 
  seg- 
  

   ment. 
  

  

  