﻿BOLBOCERATINI 
  OF 
  THE 
  UNITED 
  STATES 
  CARTWRIGHT 
  109 
  

  

  Bolbocerastes 
  imperialis, 
  new 
  species 
  

  

  Figure 
  14, 
  g; 
  Plate 
  4 
  

  

  Holotype 
  male, 
  length 
  19 
  mm., 
  width 
  11 
  mm. 
  Very 
  similar 
  to 
  

   Bolbocerastes 
  serratus 
  (LeConte) 
  ; 
  ferrugineus; 
  moderately 
  shining; 
  

   hairy 
  beneath. 
  Vertical 
  face 
  of 
  clypeal 
  horn 
  inclined 
  forward 
  about 
  

   30 
  degrees 
  from 
  perpendicular, 
  slightly 
  convex 
  when 
  viewed 
  from 
  side, 
  

   height 
  seven-tenths 
  width 
  at 
  base, 
  width 
  of 
  the 
  truncate 
  apex 
  slightly 
  

   less 
  than 
  half 
  the 
  basal 
  width, 
  the 
  apex 
  arcuate 
  posteriorly 
  at 
  

   each 
  side; 
  the 
  posterior 
  face 
  of 
  the 
  horn 
  concave 
  from 
  side 
  to 
  side 
  

   between 
  the 
  wealdy 
  carinate 
  edges, 
  which 
  converge 
  very 
  slightly 
  from 
  

   apex 
  to 
  base. 
  General 
  level 
  of 
  the 
  head 
  slightly 
  more 
  than 
  half 
  the 
  

   height 
  of 
  the 
  clypeal 
  horn 
  above 
  the 
  wide, 
  truncate 
  labrum; 
  this 
  flat- 
  

   tened 
  area 
  sloping 
  upward 
  posteriorly 
  and 
  bounded 
  by 
  a 
  ridge 
  or 
  

   carina 
  deeply 
  arcuate 
  posteriorly 
  from 
  the 
  anterior 
  edge 
  of 
  one 
  eye 
  to 
  

   the 
  other 
  and 
  continuing 
  forward 
  on 
  each 
  side 
  to 
  the 
  tips 
  of 
  the 
  weakly 
  

   elevated, 
  right-angled, 
  secondary 
  horns, 
  then 
  converging 
  to 
  the 
  an- 
  

   terior 
  edge 
  of 
  the 
  clypeal 
  horn 
  and 
  forming 
  the 
  upper 
  edge 
  of 
  the 
  tri- 
  

   angular 
  lateral 
  area 
  at 
  base 
  of 
  the 
  horn; 
  flattened 
  area 
  of 
  head 
  slightly 
  

   depressed 
  laterally 
  above 
  the 
  prominent 
  quadrangular 
  eye 
  canthus, 
  

   which 
  slopes 
  arcuately 
  downward, 
  outward, 
  and 
  finally 
  upward 
  at 
  the 
  

   outer 
  angles; 
  entire 
  surface 
  in 
  front 
  of 
  the 
  curving 
  posterior 
  ridge 
  

   densely, 
  rouglily 
  punctate, 
  smooth 
  back 
  of 
  the 
  ridge. 
  Mandibles 
  

   concave 
  dorsally; 
  strongly 
  angled 
  front 
  and 
  back. 
  

  

  Pronotum 
  retuse 
  in 
  front 
  and 
  with 
  serrate 
  lateral 
  margins 
  as 
  in 
  B. 
  

   serratus 
  (LeConte) 
  and 
  B. 
  regalis; 
  the 
  median 
  prominence 
  and 
  lateral 
  

   carinae 
  nearly 
  as 
  in 
  B. 
  regalis 
  but 
  with 
  the 
  outer 
  carina 
  with 
  the 
  upper 
  

   end 
  curving 
  slightly 
  away 
  and 
  not 
  quite 
  parallel 
  with 
  the 
  basal 
  mar- 
  

   gin 
  when 
  viewed 
  from 
  the 
  side; 
  the 
  inner 
  lateral 
  carina, 
  viewed 
  from 
  

   the 
  side, 
  with 
  the 
  lower 
  end 
  rising 
  abruptly 
  to 
  a 
  right 
  angle, 
  then 
  

   sloping 
  evenly 
  upward 
  to 
  a 
  right-angled 
  peak 
  at 
  middle, 
  then 
  down 
  

   in 
  a 
  strongly 
  sinuate 
  in-and-out 
  curve; 
  both 
  carinae, 
  viewed 
  from 
  

   directly 
  in 
  front, 
  evenly 
  arcuate, 
  with 
  the 
  peak 
  angle 
  of 
  the 
  inner 
  carina 
  

   strongly 
  bent 
  inward; 
  the 
  median 
  prominence 
  slightly 
  constricted 
  

   toward 
  the 
  base, 
  with 
  the 
  sides 
  weakly 
  angulate 
  in 
  front 
  of 
  the 
  con- 
  

   striction 
  and 
  the 
  surface 
  more 
  broadly 
  and 
  less 
  deeply 
  concave 
  from 
  

   side 
  to 
  side 
  than 
  in 
  B. 
  regalis 
  and 
  evenly 
  arcuate 
  from 
  front 
  to 
  back; 
  a 
  

   distinct 
  median 
  line 
  evident 
  basally; 
  the 
  apical 
  and 
  deeper 
  lateral 
  

   pronotal 
  depressions 
  extending 
  upward 
  between 
  the 
  lateral 
  carinae; 
  

   the 
  median 
  prominence 
  impunctate 
  except 
  for 
  half 
  a 
  dozen 
  or 
  so 
  close, 
  

   moderate 
  punctures 
  on 
  each 
  side 
  at 
  base 
  of 
  the 
  vertical 
  sinus; 
  above 
  

   these 
  about 
  twenty 
  or 
  so 
  scattered 
  fine 
  punctures 
  on 
  the 
  inner 
  slope 
  

   of 
  the 
  vertical 
  sinus, 
  and 
  a 
  very 
  few 
  fine 
  punctures 
  indicating 
  a 
  sub- 
  

   apical 
  line; 
  median 
  prominence 
  and 
  lateral 
  basal 
  area 
  back 
  of 
  the 
  

  

  