Skip to main content

Full text of "Insect behavior"

See other formats


SGCT  BCHAVIOR 


AUL  GRISWOLD  HOW€S 


INSECT  BEHAVIOR 


BADGER'S 
STUDIES    IN    SCIENCE 


THE  HIGHER  USEFULNESS  OF  SCIENCE. 
By  William  Emerson  Ritter. 

THE  UNITY  OF  THE  ORGANISM,  OR  THE 
ORGANISMAL  CONCEPTION  OF  LIFE.  Two 
volumes.  Illustrated.  By  William  Emer- 
son Ritter. 

THE  BEGINNINGS  OF  SCIENCE.  By 
Edward  J .  Menge. 

THE  PROBABLE  INFINITY  OF  NATURE 
AND  LIFE.  By  William  Emerson  Ritter. 

AN  ORGANISMAL  CONCEPTION  OF  CON- 
SCIOUSNESS. By  Wittiam  Emerson  Ritter, 

INSECT  BEHAVIOR.  Illustrated.  By 
Paul  G.  Howes. 

LIFE  AND  DEATH,  HEREDITY  AND  EVOLU- 
TION IN  UNICELLULAR  ORGANISMS.  Illus- 
trated. By  H.  S.  Jennings. 

THE  ORNITHOLOGY  OF  CHESTER  COUNTY, 
PENNSYLVANIA.  Illustrated.  By  Frank 
L.  Burns. 

FAMILIAR  STUDIES  OF  WILD  BIRDS.  Illus- 
trated. By  F.  N.  Whitman. 

QUESTIONS  AND  OUTLINES  IN  GENERAL 
CHEMISTRY.  By  W.  S.  Haldeman. 


RICHARD   G.   BADGER,   PUBLISHER,   BOSTON 


'They  hover  over  the  expanse  below,  occasionally  swooping  down  upon  creatures  of  lesser  bulk" 
JJschnid  dragon-fly  feeding  upon  a  house  fly.     Much  enlarged 


INSECT    BEHAVIOR 


BY 


WITH  ILLUSTRATIONS  FROM 
PHOTOGRAPHS  BY  THE  AUTHOR 


BOSTON 
RICHARD  G.  BADGER 

THE  GORHAM  PRESS 


COPYRIGHT,  igig,  BY  RICHARD  G.  BADGER 


All  Rights  Reserved 


Made  in  the  United  States  of  America 


The  Gorham  Press,  Boston,  U.  S.  A. 


TO 

MY     MOTHER 

WHOSE   FAITH   AND  ENCOURAGEMENT 
HAVE    PAVED   THE   WAY 

THIS     BOOK     IS     FONDLY     DEDICATED 


PREFACE 

IN  preparing  this  little 'volume  my  object  has  been  to  produce 
a  work  written  in  a  light  enough  vein  to  be  entertaining  to  the 
reader,  however  casually  interested  he  may  be  in  insect  life,  but 
at  the  same  time,  one  that  is  in  every  way  scientifically  accurate. 
In  the  chapters  which  follow,  I  have  endeavored  to  describe  as 
vividly  as  it  lies  within  my  power  to  do,  various  phases  of  insect 
behavior  which  I  have  been  fortunate  enough  to  observe  and  record 
during  many  years  spent  in  active  field  work. 

Chapters  II  to  VIII  inclusive,  treat  exclusively  of  South  American 
insects,  studied  in  the  jungles  of  British  Guiana,  and  while  they  are 
interesting  species,  whose  habits  have  heretofore  remained  un- 
recorded, they  possess  no  more  wonderful  life  stories  than  our  insects 
of  the  Eastern  States,  whose  habits,  for  the  most  part,  make  up  the 
remainder  of  this  book. 

Wherever  one  searches  in  the  world  of  insects  there  is  something 
new  to  be  found.  Perhaps  only  an  unrecorded  habit,  or  a  slight 
problem  to  be  solved,  yet  each  problem  leads  to  another,  and  soon  one 
is  led  unconsciously  into  the  depths  of  the  study.  Once  in,  there 
appears  to  be  no  way  out,  and  I  for  one  do  not  wish  to  retrace  my 
steps  to  the  freedom  I  knew  before  the  fascination  of  this  study  laid 
hold  of  me. 

If  this  book  leads  others  into  the  world  of  insect  study  or,  in  some 

measure,  brings  home  to  the  reader,  the  same  fascination  that  these 

life  stories  hold  for  the  author,  then  its  object  will  be  fully  realized. 

For  the  use  of  chapters  II  to  VIII  inclusive,  which  originally 

appeared  in  Volume  I  of  Tropical  Wild  Life  in  British  Guiana,  I  am 


io  PREFACE 

greatly  indebted  to  the  New  York  Zoological  Society,  and  to  those 
magazines  who  have  published  other  chapters  as  separate  articles, 
and  have  now  given  their  consent  to  their  use  in  this  book,  I  wish 
also  to  acknowledge  my  grateful  thanks. 

Last  but  not  least,  to  Lillian  Carey  Howes,  upon  whom  has  fallen 
the  main  burden  of  preparing  my  manuscript  for  the  printer,  I  make 

grateful  acknowledgment. 

PAUL  GRISWOLD  HOWES. 
Stamford,  Conn., 

January  i,  1918. 


CONTENTS 

CHAPTER  PAGE 

I    THE  INSECT  WORLD  AT  CLOSE  RANGE 19 

II    THE  BLACK  REED-WASP 27 

III  LARVAL  SACRIFICE 33 

IV  THE  WHITE-FOOTED  WASP 40 

V    PARALYZED  PROVENDER 46 

VI    THE  FOREST  SHELL-WASP 53 

VII    THE  ONE-BANDED  DAUBER 60 

VIII    THE  BLUE  HUNTRESS 68 

IX    CONTROLLED  PUPATION 77 

X    CANNIBAL  WASPS 85 

XI    THE  SPHECID'S  DUTY 91 

XII    THE  ORIGINAL  PAPER-MAKERS 95 

XIII  INSECT  AND  OTHER  STRATEGISTS 102 

XIV  OBSERVATIONS  ON  ANTS 109 

XV    THE  SIGHT  OF  INSECTS 125 

XVI    How  THE  GREENBOTTLE  DOES  ITS  DUTY 129 

XVII    SOME  INSECT  EXPERIMENTS 134 

XVIII    THE  CECROPIA  MOTH 143 

XIX    NATURE'S  WAY  WITH  UNDESIRABLES 147 

XX    SPITTLE  BUG  SPITTLE 151 

XXI    THE  LIFE  OF  THE  THREAD-LEGGED  BUG 154 

XXII    TRAILING  A  BEE  TO  ITS  LAIR 160 

XXIII  CAMOUFLAGED  INSECTS 164 

XXIV  LIVING  EXAMPLES  OF  THE  GEOLOGICAL  PAST      .     .     .     .  169 
INDEX 173 


ii 


LIST  OF  ILLUSTRATIONS 

FACING  PAGE 

^Eschnid  dragon-fly  preying  upon  a  house  fly Frontispiece-  _ 

A  centipede  greatly  enlarged 21 

Grasshoppers  fighting 21 

Staphylinid  beetle  preying  upon  a  fly 22— 

An  assassin  bug  laying  her  eggs 24 

A  handful  of  vegetation  at  close  range 26 

A  photograph  made  under  asparagus  plants 26 

Plough  furrows  are  as  mountain  ranges  to  the  insects ".  31 

A  greatly  enlarged  hemipterous  insect 31 

Male  black  reed-wasp  guarding  nesting  tube 33 

Female  black  reed-wasp  arriving  at  the  tube 33 

Glass  tube  removed  from  box,  showing  plugs,  egg  and  spiders        ....  33 

Old  nest  of  wasp  used  by  the  black  reed-wasp 33 

Stages  in  the  larval  sacrifice 35 

Newly  transformed  pupa  of  the  roach-killer 35-" 

Spider  used  as  provender  by  the  white-footed  wasp 40 

Cocoon  of  white-footed  wasp 40 

Tangle  of  reeds  and  razor  grass  in  British  Guiana 40 

Two  common  bugs  which  do  great  damage  to  squash  vines 49 

Open  nest  of  the  forest  shell-wasp 56 

Open  nest  and  larva  of  the  forest  shell-wasp 56 

Newly  emerged  one-banded  dauber 65 

Suspended  hatching  egg  of  the  forest  shell-wasp 65 

One-banded  dauber  working  upon  her  nest 65 

Four  types  of  nests  made  by  the  one-banded  dauber 65 

Spider  prey  and  egg  of  the  blue  huntress 68 

Pupa  of  the  blue  huntress  showing  T-shaped  jacks 68 

A  queen  paper  wasp  at  her  nest 72 

A  cabbage  butterfly  depositing  an  egg following  76 

13 


14  LIST  OF  ILLUSTRATIONS 

FACING  PAGE 

Cocoons  of  ichneumon  parasite  of  cabbage  butterfly  larva 76 

Male  and  female  paper-wasps  hatching  in  July          81 

Paper-wasp  worker  with  unusually  large  pellet  of  paper 81 

The  cannibal's  nest  layed  open 85 

A  cannibal  wasp  at  her  nest 85 

The  cannibal  and  her  diggings 86 

A  complete  lead  model  of  the  cannibal  wasp's  burrow 86 

A  wasp  of  the  sphecid's  size  compared  to  a  rove  beetle 88 

Sphecid  wasp  dragging  a  paralyzed  cicada  to  her  burrow 88 

Common  cicada,  upon  which  the  sphecid  wasp  preys 88 

Comparative  wing  expanse  of  cicada  and  sphecid  wasp 90 

Hole  in  cicada  through  which  the  young  sphecid  entered 90 

Young  sphecid  wasp  two  days  old  feeding  on  its  host 90 

Queen  paper  wasp  in  the  act  of  depositing  an  egg following  92 

Photomicrograph  of  eggs  of  the  paper  wasp following  92 

Paper  wasp  cells  showing  young  and  silken  cocoon-caps 95 

Life  size  nest  of  paper-wasp 95 

Cells  of  the  paper-wasp  with  caps  removed  to  show  young 97 

Paper  wasp  cells  in  section  showing  larva  and  pupa 99 

Epeira  insularis,  an  orb-building  spider,  laying  eggs 102 

A  spider  using  a  cicada's  shell  as  a  hiding  place         104 

An  example  of  spider  strategy 104 

The  fishing  net  of  a  hydropsychid  and  its  maker 106 

Ants  surrounding  and  pillaging  a  larger  one following  108 

Brown  ants  transporting  aphids  to  their  underground  nest       .      .   following  108 

Actual  debris  gathered  up  after  an  ant  battle following  108 

Carpenter  ants  tending  their  aphid  "cattle" following  108 

Paralyzed  and  dying  South  American  leaf-cutter  ants in 

A  group  of  dead  ants  all  linked  together in 

Carpenter  ants  proceeding  to  battle 113 

A  severed  head  of  an  enemy  clinging  to  a  dead  ant 113 

A  train  of  South  American  army  ants 113 

Leaf-cutter  ants  with  heads  and  abdomens  eaten  away 113 

Young  brown  ants  carefully  tended  by  their  nurses 115 

Young  brown  ants  brought  up  beneath  a  sun-warmed  stone 115 


LIST  OF  ILLUSTRATIONS  15 

FACING  PAGE 

A  snowy  tree  cricket  singing 118 

The  typical  dragon-fly  face 120 

A  robber-fly  with  its  prey 120, 

Photomicrograph  through  the  eye  windows  of  a  fly 122 

A  harvestman following  124 

Egg  mass  of  the  greenbottle  fly following  124 

A  greenbottle  laying  eggs  upon  the  head  of  a  dead  bird 127 

Greenbottle  laying  eggs  in  the  bill  of  a  starling 127 

Young  greenbottle  flies  at  work 129 

Skeleton  of  a  muskrat  cleaned  by  young  greenbottle  flies 131 

Test  tubes  containing  foods  liquefied  by  young  flies 131 

Nest  of  the  mound-building  ants 134 

Cecropia  caterpillars  twenty-five  days  old 138 

Cecropia  caterpillar  casting  its  skin 138 

Caterpillars  of  the  cecropia  just  after  the  second  cast 138 

Eggs  of  the  cecropia  on  an  apple  leaf        138 

Female  cecropia  moth 143 

The  full  grown  cecropia  caterpillar 143 

Newly  completed  cocoon  of  the  cecropia  caterpillar 143 

Squash  flower  opened  to  show  nectar  cup 147 

How  the  honey  bee  reaches  the  nectar  in  a  squash  flower 147 

A  beetle  at  the  entrance  of  the  nectar  cup 147 

Fertilized  blossoms  of  the  squash  plant 148 

The  yellow  gaping  throat  of  a  squash  flower 148 

Foamy  dwellings  of  immature  spittle  bugs 150 

Growth  of  the  spittle  mass         150 

A  dried  spittle  mass  and  the  mature  insect 152 

Huge  spittle  mass  found  in  the  jungle  of  British  Guiana 152 

A  thread-legged  bug  laying  eggs 154 

A  stampede  of  thread-legged  bugs 156 

Greatly  enlarged  head  of  the  thread-legged  bug following  156 

A  characteristic  attitude  of  the  thread-legged  bug following  156 

A  thread-legged  bug  casting  its  skin 157 

Spring-tails  in  their  tiny  world 159 

Spring-tails  showing  spines  upon  their  bodies 159 


16  LIST  OF  ILLUSTRATIONS 

FACING  PAGE 

A  tiny  solitary  bee  resting  between  journeys 161 

Making  a  plaster  cast  of  the  bee's  burrow 161 

Entrance  to  the  bee's  tunnel  showing  surroundings 161 

Model  of  the  bee's  nest  made  from  a  plaster  cast 163 

Interior  of  the  bee's  burrow  showing  cell  and  food 163 

Excavating  the  cast  of  the  burrow 163 

Caterpillar  of  a  geometrid  moth  which  resembles  a  twig      .      .      .   following  164 

Caterpillar  which  mimics  the  excretia  of  a  bird following  164 

Chrysalis  of  the  mourning  cloak  butterfly 168 

Cochlidiid  caterpillar  which  mimics  a  leaf-bud     .      . 168 

Thread-legged  bug  in  its  original  environment following  170 

Poison  spines  of  the  lo  caterpillar following  170 

Wood  lice  or  pill  bugs .  173 

A  thysanuran  or  bristle-tail 173 


INSECT   BEHAVIOR 


INSECT    BEHAVIOR 

CHAPTER  I 

THE  INSECT  WORLD  AT  CLOSE  RANGE 

NOT  so  long  ago  my  world  was  commonplace ;  even  dull  at 
times.  Tranquil  and  uninteresting,  until  one  day  a  tiny 
voice  broke  the  silence  of  my  study.  It  led  me  from  my 
dusty  chimney  corner,  dropped  me  suddenly  into  the  new 
and  fevered  world  of  insects,  and  there  it  left  me. 

Who  can  tell  how  long  this  new  world  had  lain  before  me  un- 
noticed, a  world  of  tiny  people  within  our  own  big  world,  fighting 
out  their  destinies  beneath  our  very  feet?  I  found  it  a  land  of  marvels 
and  excitement,  where  great  geographical  upheavals  are  but  momen- 
tary matters;  where  changes,  rivaling  those  wrought  by  a  million 
years  in  our  environment,  occur  from  day  to  day,  a  land  where  there 
is  no  uniformity  of  change.  I  found  disorder  and  repose  walking 
hand  in  hand,  neither  more  of  one  than  the  other,  yet  much  of  both. 
I  stopped;  marveled,  became  fascinated,  with  this  land  so  new  and 
mysterious,  into  which  I  could  step  without  effort,  from  my  study 
door. 

There  were  jungles,  immense  ones,  rank  and  tangled,  grown  with 
gigantic  trees  whose  bark  was  an  armor  of  thorns.  Myriad  life 
inhabited  them,  and  a  thousand  different  creatures  prowled  about 
hunting  one  another.  In  the  tree  tops,  along  their  swaying  trunks 
and  in  the  tangles  below,  every  living  thing  was  fighting  for  exist- 
ence. Were  our  ears  attuned  to  the  vibrations  of  this  jungle,  a  terri- 

19 


20  INSECT  BEHAVIOR 

fying  sound,  dwarfing  all  others,  would  reach  them,  a  grinding  of 
life  between  myriad  jaws,  merciless,  endless,  for  such  is  life  in  this 
new  world. 

Such  an  existence  in  such  a  forest  is  beyond  our  comprehension.  It 
is  the  exception  to  survive  long  here.  Each  species  preys  upon,  or 
fights  to  exterminate  the  next.  There  are  serpents  of  great  length 
and  colossal  rodents  that  comparatively  dwarf  a  mastodon,  which 
add  to  the  excitement  of  life.  It  is  fortunate  that  the  creatures 
peopling  such  a  world  possess  little  if  any  intelligence.  Indeed  it  is 
possible  that  they  were  purposely  deprived  of  it  lest  they  fear  to 
venture  forth. 

Now  this  jungle  may  flourish  into  a  great  wilderness,  a  forest 
whose  real  floor  the  sun  never  reaches.  Here  among  the  buts  of  the 
trees,  weird  creatures  are  encountered.  Ugly  crab-like  things  that 
suck  the  blood  of  others,  minute  horny  creatures  and  indescribable 
crawling  ones  whose  life  story  and  functions  nobody  yet  knows. 

Above  the  dead  fallen  stems  that  cover  this  tomb  life,  a  second 
group  of  living  things  is  encountered.  Larger  creatures  capable  of 
utterances  of  a  harsh  nature,  hard  shelled  beasts  and  triangular- 
bodied  ones  that  emit  disgusting  odors. 

One  night  the  jungle  flourishes,  green  and  rich  with  swaying,  surg- 
ing life  and  energy,  but  the  next  night  it  has  vanished.  Every  tree 
has  fallen  by  some  mysterious  hand;  millions  of  creatures  perish 
and  all  is  confusion.  What  has  occurred  claims  a  greater  toll  than 
war,  yet,  as  we  shall  see,  it  is  by  no  means  a  miracle. 

Beyond  the  vanishing  jungle  lies  a  country  of  another  type,  the 
like  of  which  no  human  being  has  ever  seen. 

Imagine  a  series  of  parallel  mountain  ranges,  three  hundred  in 
number,  of  great  length,  with  as  many  narrow  valleys  lying  between. 
The  country  is  nearly  barren  yet  strangely  rich  in  soil.  At  great 
distances  some  green  thing  finds  courage  to  lift  its  head,  standing 


Minute  horny  creatures  and  indescribable  crawling  ones  whose  life  story  and  functions  nobody  yet  knows' 

A  centipede  greatly  enlarged 


in  our  own  big  world  fighting  out  their  destinies  beneath  our  very  feet" 
Grasshoppers  fighting 


THE  INSECT  WORLD  AT  CLOSE  RANGE          21 

out  like  a  palm  in  an  oasis,  giving  its  mite  of  shelter  from  the  sun. 
Lying  about  in  no  order,  one  sees  great  boulders,  some  rounded,  others 
with  jagged  dangerous  edges  and  many  bearing  white  wounds  as 
though  a  giant  hammer  had  tried  to  cleave  them. 

There  is  a  scarcity  of  animal  life  here  just  as  there  is  a  scarcity  of 
vegetation,  but  one  or  two  creatures  revealed  by  the  hunt  are  inter- 
esting. 

One  possesses  a  bony  orange  head  that  glistens  like  polished  armor. 
It  is  armed  additionally  with  heavy  curved  rusks,  working  sidewise 
with  great  strength,  but  for  all  this  war-like  apparatus  its  body 
is  fat  and  pudgy.  Such  a  hypocrite  could  be  attacked  from  behind 
with  safety.  The  creature  rolls  about  aimlessly  and  one  is  forced 
to  wonder  how  it  obtains  its  food. 

Another  is  a  hairy  eight  eyed  creature,  possessed  of  as  many  agile 
legs  that  carry  it  rapidly  from  place  to  place.  It  lives  in  damp  caves 
beneath  boulders,  darting  out  upon  the  unwary.  In  the  seclusion 
of  its  cave  it  sucks  its  victim's  blood  casting  out  the  skeleton  as  a 
warning  to  others. 

We  pass  on.  The  journey  brings  us  through  another  jungle  of 
immense  fruit  trees  bearing  large  objects  resembling  cocoanuts  and 
thence  to  a  lake  of  great  extent,  backed  up  by  a  group  of  mountains. 
Over  the  water  one  sees  large  flying  creatures,  with  tremendous  eyes 
and  slender,  plated  bodies.  They  hover  over  the  expanse  below, 
occasionally  swooping  down  upon  creatures  of  lesser  bulk,  whom  they 
consume  greedily. 

In  front  of  us  there  are  slimy  flats  sloping  toward  the  lake.  Puffs 
of  tainted  air  lead  to  the  discovery  of  a  mass  of  carrion  near  the 
water's  edge.  Here  is  something  of  interest. 

Upon  the  manna  a  multitude  of  animals  are  gorging.  Most  of 
them  are  similar  in  body,  being  long,  fleshy  and  alert.  They  appear 
to  be  fighting  greedily  for  the  repast  upon  which  they  are  exuding 


22  INSECT  BEHAVIOR 

a  strange  fluid  to  assist  digestion.  They  move  continually  about  by 
means  of  grapnels  which  enable  the  animals  to  progress  either  for- 
ward or  backward  by  repeated  contractions  of  their  muscles. 

Other  animals  are  attracted  by  the  odor  of  decay  and  from  far 
and  near  they  come  to  seek  the  cause.  Some  to  their  advantage, 
others  to  their  detriment,  for  a  cannibal  lies  in  wait  for  them. 

It  is  a  powerful  animal,  slender  and  supple-bodied,  with  a  coat  of 
glossy  bronze  velvet.  It  is  perhaps  the  most  active  of  all  the  weird 
creatures  that  we  have  come  to  know,  moving  like  a  flash  in  response 
to  stimulae.  It  could  not  exist  were  patience  a  necessity,  at  least  one 
is  so  impressed  upon  observing  it. 

There  are  many  tunnels  twisting  into  the  carrion,  excavated  by 
other  creatures,  and  one  of  these  the  cannibal  selects  for  its  abode, 
until  the  flesh  becomes  too  dry  to  act  as  lure.  In  this  grewsome  cave 
the  creature  rests,  its  eyes  roving  and  its  whole  body  ready  to  spring  at 
an  instant's  notice,  which  it  does  upon  all  who  venture  within  its 
range.  Indeed  we  have  found  a  veritable  dragon  in  this  creature 
so  fiery  and  ready  for  battle.  Its  prey  is  helpless  before  the  on- 
slaught and  its  teeth  sink  easily  through  armor. 

Leaping  upon  the  back  of  its  victim,  the  dragon  tears  deep  into 
its  body,  grinding  flesh  and  skeleton,  sucking  every  drop  of  blood 
until  the  broken  creature  curls,  dry  like  a  leaf.  In  a  few  seconds 
the  unlucky  one  has  disappeared  before  our  eyes.  A  minute  ago 
we  saw  a  living  creature  come  to  the  carrion  to  stay  its  appetite. 
Next  we  heard  a  crunching  noise  and  saw  a  splash  of  blood.  Now 
there  is  nothing  but  the  retreating  cannibal  and  we  gaze  dumb- 
founded at  the  spot  where  the  scene  was  enacted. 

From  the  lake  we  journey  on,  through  a  wide  and  heavy  section 
of  woodland,  on  our  way  to  the  desert  that  lies  beyond.  As  we  go 
we  have  many  weird  experiences  and  see  many  curious  sights,  but 
lack  of  time  prevents  their  proper  observation.  We  must  reach  the 


s   >> 


THE  INSECT  WORLD  AT  CLOSE  RANGE          23 

desert  at  once,  lest  we  arrive  too  late  to  see  the  pitfalls  of  the  desert 
lions. 

At  length  the  broiling  sands  are  reached  and  none  too  soon.  The 
lions  only  build  their  traps  at  certain  times  of  the  year  and  few  signs 
of  them  are  encountered.  A  search  reveals  four  pits,  however,  placed 
in  the  neighborhood  of  a  colony  of  burrowing  creatures  common  to 
the  desert. 

The  pits  are  deep  conical  excavations  in  the  sand,  so  cunningly 
constructed  as  to  compel  admiration  despite  the  clumsy  makers, 
who  walk  backwards  in  preference  to  forward. 

At  this  time  the  lions  are  still  youthful  and  being  grotesque  and 
cumbersome  of  body,  must  therefore  secure  their  prey  by  strategy. 
Each  individual  excavates  a  pitfall,  cone-shaped  as  we  have  seen. 
At  the  apex  of  the  cone,  which  is  deep  in  the  ground,  the  creature 
conceals  itself  with  only  the  sabre-like,  sand-colored  mandibles 
protruding. 

Let  us  watch  from  a  safe  distance  the  methods  employed.  We 
have  not  long  to  wait,  for  a  constant  stream  of  animals  are  pouring 
in  and  out  of  their  burrows  near  by.  Many  keep  at  a  safe  distance; 
others  escape  more  through  good  fortune  than  intelligence,  but  at 
length  a  stupid  individual  arrives  at  a  pit  and  heedlessly  places  one 
foot  over  the  edge. 

At  once  the  footing  crumbles  and  the  poor  animal  starts  on  its 
journey.  Once,  in  its  frantic  struggles,  it  appears  to  regain  the  lost 
footing,  but  seeing  or  expecting  this,  the  lion  hurls  a  multitude  of 
rocks  from  below,  which  once  more  start  the  sand  sliding  and  the 
victim  meets  its  death  in  merciless,  waiting  jaws. 

Now  we  might  travel  on  and  on,  from  the  desert  to  another  valley, 
lying  between  inspiring  mountain  chains,  thence  to  a  dried  up  ocean 
bed,  across  a  great  river  into  more  jungle  and  so  on,  indefinitely,  wit- 


24  INSECT  BEHAVIOR 

nessing  an  endless  series  of  geographical  and  living  wonders  that 
would  soon  bewilder  us. 

We  can  go  no  further  now.  Our  expedition  into  the  new  world 
must  needs  come  to  an  end.  Before  we  return  home,  we  are,  how- 
ever, to  witness  the  approach  and  arrival  of  a  new  period.  We  are  to 
see  with  our  own  eyes  and  in  a  very  short  time,  the  temporary  death 
of  this  curious  land. 

The  period,  which  is  a  glacial  one,  comes  rapidly  and  is  marked 
by  great  frosts,  capable  of  killing  an  entire  jungle  in  a  single  night. 
With  each  successive  frost,  countless  millions  of  creatures  perish, 
the  weakest  dying  at  once,  the  stronger  surviving  for  a  slightly  longer 
period.  Lakes  and  oceans  freeze  solid  from  surface  to  their  depths, 
valleys  and  mountains  are  buried  with  snow  and  in  an  incredibly 
short  time,  perhaps  a  month  or  two,  life  in  this  lately  flourishing  land 
through  which  we  have  traveled  may  be  cold  and  dead. 

A  glacial  period  has  come,  transforming  the  land  into  a  desolate 
waste.  It  has  apparently  carried  all  life  before  it. 

A  fertile  earth  today,  a  barren  moon  tomorrow,  such  is  this  new 
world  within  our  own! 

******* 

Let  us  now  see  just  what  this  new  world  is  and  where  our  travels 
have  led  us.  We  have  barely  looked  into  its  treasure  house  of  won- 
ders, but  for  all  that,  we  have  learned  something  and  our  eyes  have 
been  opened  to  its  possibilities. 

Its  geography  is  our  own,  more  minutely  seen,  analyzed  as  it  were 
into  its  smallest  parts.  To  study  its  wonders  one  must  lose  sight 
of  all  large  unimportant  things.  Real  mountains,  lakes,  deserts, 
objects  that  make  our  geography,  all  must  be  ignored.  They  are 
too  evident  to  be  considered  and  to  bother  with  them  as  a  whole 
would  be  like  hoarding  something  without  value. 

If  we  examine  a  great  painting  closely,  we  see  only  a  melee  of  mean- 


Another  strange  creature  of  the  insect  world 

An  assassin  bug  laying  her  eggs 

Enlarged  six  times 


THE  INSECT  WORLD  AT  CLOSE  RANGE          25 

ingless  strokes;  dabs  of  color  placed  together  like  the  patches  of  a 
crazy  quilt.  So  we  may  liken  this  new,  or  insect  world,  to  these 
strokes  and  dabs  that  collectively  make  the  painting.  In  a  word  the 
new  world  consists  of  the  particles  that,  heaped  together,  compose  the 
mountain,  the  valley  and  the  desert  of  our  own. 

When  we  were  coaxed  from  our  study  by  the  excitement  of  dis- 
covery, we  stepped  across  the  lawn  into  a  field  of  waving  hay.  It 
was  bordered  with  a  heavy  growth  of  weeds  and  other  vegetation. 
Stopping  to  analyze,  we  found  a  jungle  of  the  insect  world.  At  the 
other  end  of  the  field  the  farmers  were  already  swinging  their 
scythes — thus  the  jungle  vanished  in  a  day. 

We  journeyed  on  to  another  field,  so  recently  turned  over  by  the 
plough  that  vegetation  had  only  appeared  at  intervals.  There  were 
three  hundred  furrows,  mountain  ranges  to  an  insect.  There  were 
stones  bearing  plough  wounds,  a  few  drassid  spiders  under  them  and 
here  and  there  a  fat  white  grub  rolling  helplessly  about. 

Next  we  passed  through  a  patch  of  asparagus  with  its  rounded  fruit. 
Beyond  this  a  clear  little  puddle  was  sighted  over  which  dragon 
flies  hovered,  occasionally  swooping  down  upon  smaller  insects.  The 
far  bank  of  the  puddle  was  composed  of  sand  and  stones  heaped  to- 
gether like  conglomerate,  but  in  front  was  a  muddy  flat  upon  which 
some  frightened  creature  had  dropped  its  animal  prey. 

In  the  flesh  of  this  unfortunate  we  found  a  swarm  of  maggots, 
young  flies  whose  duty  it  is  to  liquefy  such  objects  and  return  death  to 
life.  Beneath  the  carrion  a  rove  beetle  lay  in  wait  for  unwary  mother 
flies  who  came  to  lay  their  eggs  in  the  game. 

Leaving  the  pond  for  pastures  new,  we  crossed  a  sandy  field.  Here 
several  ant  lions  had  made  their  pitfalls  to  entrap  blundering  ants,  in 
whose  formic  acid  they  find  nourishment  and  a  pleasing  flavor. 

And  so  we  might  travel  on  and  on,  endlessly  were  it  not  for  winter. 
Frosts  are  messengers  of  death  in  the  insect  world.  Each  drop  of 


26  INSECT  BEHAVIOR 

the  mercury  reduces  its  myriad  life  until  at  length  there  is  nothing 
left.  We  witness  the  coming  of  the  frosts,  then  the  snows,  exter- 
minating all  the  little  people  that  we  have  learned  to  know,  for  with 
winter  comes  the  temporary  death  of  their  world.  A  queer  little 
world  that  may  be  a  fertile  earth  today  and  a  barren  moon  tomorrow. 


o     « 


o  ^ 

Z  o 

•=  2 

vS  £ 

H 
a 


0  -w 
_C  rt 

*  e 

05  .2 

1  ^ 


THE  BLACK  REED-WASP 

Trypoxylon  cinereohirtum,  Cam 

WHERE  man  has  felled  the  primitive  forest,  obliterat- 
ing nature's  labors  of  half  a  thousand  years,  he  leaves 
a  wound  that  is  long  in  healing.     Just  as  a  wound  in 
the  flesh  leaves  a  scar  that  stands  out  distinct  from  its 
surroundings,  so  the  forest  heals  its  injury  with  a  new  vegetation, 
distinct  from  itself,  but  a  mask  nevertheless  to  the  ghastly  wound 
lying  beneath. 

We  call  the  mask  second  growth.  It  is  made  up  of  trumpet  trees, 
weakly  shoots  from  fallen  forest  giants,  great  waves  of  razor-grass, 
briars,  various  types  of  undergrowth  and  here  and  there  a  patch  of 
canes  whose  hollow  stems  are  the  natural  nesting  sites  of  the  black 
reed-wasps. 

Abandoning  their  natural  habitat  for  the  advantages  afforded  by 
Kalacoon,1  they  flocked  to  our  hospitable  board,  setting  up  their 
abodes  in  our  pen-holders,  in  spools,  nail  holes,  in  the  handle  of  my 
shaving  glass,  and,  in  fact,  in  anything  that  suggested  a  hollow  tube 
with  a  tiny  diameter. 

To  the  general  rule  among  Hymenoptera  2  the  black  reed-wasps 
are  an  exception.  That  is  to  say,  they  are  neither  social,  in  the  usual 
community  sense  of  the  word,  nor  are  they  solitary.  They  came  in 
mated  pairs  in  search  of  nesting  sites,  inspecting  all  the  best  holes 

*A  laboratory  in  the  jungles  of  British  Guiana  where  the  author  encountered  the 
subject  of  this  chapter. 

2  An  order  of  insects  including  ants,  bees,  wasps,  etc. 

27 


28  INSECT  BEHAVIOR 

in  the  house  with  great  care  and  deliberation.  Like  so  many  newly 
married  couples,  filled  with  the  enthusiasm  of  a  novel  project,  they 
roamed  about  among  the  improved  property  that  Kalacoon  offered. 
To  facilitate  my  studies  of  their  life  history,  I  placed  several  pieces 
of  glass  tubing,  three  or  four  inches  long  and  a  quarter  of  an  inch 
in  diameter,  about  the  laboratory.  I  inserted  the  tubes,  which  were 
closed  at  one  end,  into  pasteboard  boxes,  leaving  the  open  end  of 
each  projecting,  so  that  the  entrances  were  in  plain  view,  but  the 
main  part  of  the  passages  were  quite  dark,  within  the  boxes.  Thus  I 
made  conditions  in  the  tubes  exactly  like  those  in  the  reeds  that  the 
insects  naturally  chose  for  their  nests. 

They  were  an  instant  success,  and  within  an  hour  or  two,  all  were 
occupied  by  enthusiastic  couples.  In  the  glass  nests,  I  could  watch 
everything  that  went  on.  All  that  was  necessary  for  me  to  do  in 
order  to  observe  the  occupants'  behavior,"  was  to  remove  the  box 
covers,  and  replace  them  when  I  had  finished. 

True  to  the  tradition  of  wasp  history,  the  female  proceeds  with 
the  hard  labor  of  nest  building  and  providing  for  her  family.  The 
male,  while  he  never  actually  takes  part  in  the  work,  sits  menacingly 
in  the  entrance,  during  his  mate's  absence,  guarding  the  nest  from 
intruders  of  the  same  species  that  are  ever-ready  unbidden  to  acquire 
a  partly  prepared  home.  He  shows  great  interest  in  the  work,  fol- 
lowing the  female  into  the  tunnel,  watching  closely  whatever  she  may 
be  doing  and  squeaking  continually  in  a  high  pitched  key  by  vibrating 
his  wings.  This  is  a  common  habit  among  many  wasps  during  work 
hours,  but  the  species  in  question  emits  this  strange  little  rasping 
sound  during  almost  all  of  its  occupations.  I  interpret  it  as  an 
expression  of  pleasure  or  well-being,  like  a  man  who  whistles  at  his 
job.  The  sound  is  never  heard  during  fright  or  anger,  but  of  this 
I  shall  treat  in  another  chapter. 

Upon  occupying  a  tube,  the  female's  first  procedure  is  to  place 


THE  BLACK  REED-WASP  29 

a  plug  of  solid  mortar  in  the  end  of  it,  doubtless  to  prevent  parasites 
and  ants  from  entering.  This  plug  is  two  millimeters  in  thickness 
and  composed  of  wet,  light  gray  clay.  It  dries  in  a  few  hours,  harden- 
ing into  a  tough  cement.  Next  to  this,  a  second  plug,  one  millimeter 
in  thickness,  is  placed,  containing  more  moisture  than  the  first  and 
of  a  much  darker  shade.  This  is  followed  by  a  third  one  of  the 
same  description,  placed  five  or  six  millimeters  in  front  of  the  second 
plug,  so  that  there  is  an  air  space  between  them  which  holds  moisture 
in  the  nest.  The  tube  is  now  provisioned  with  small  spiders  of  dif- 
ferent species,  varying  from  five  to  eight  in  number,  wrhich  are 
paralyzed  by  the  wasp's  sting  and  brought  in  one  by  one.  They  are 
packed  tightly  into  the  tube  by  the  insect's  broad  head  wrhich  is 
brought  into  use  as  a  sort  of  ramrod.  The  tube  is  a  tiny  muzzle- 
loader,  into  which  she  packs  her  living  wads  without  mercy. 

Upon  the  side  or  apex  of  the  last,  and  usually  the  largest,  spider's 
abdomen,  she  deposits  a  milky-white,  bow-shaped  egg,  two  milli- 
meters in  length.  It  is  less  than  one-quarter  as  wide  as  long  and 
closely  resembles  a  sausage.  The  spiders  and  the  egg  are  now  en- 
closed in  a  substantial  cell  averaging  twenty  millimeters  in  length,  by 
the  insertion  of  a  double  plug  of  mortar,  six  millimeters  in  thickness, 
half  of  damp,  dark-colored  clay  and  half  of  the  hard  lighter  material. 
The  nest  is  now  abandoned  by  the  parent  wasps  who  often  start  imme- 
diately to  provision  a  second  one. 

In  two  days  the  egg  hatches,  bringing  to  light  a  yellow-white  grub 
of  thirteen  segments.  It  commences  feeding  at  once  upon  the 
spiders,  a  process  which  may  be  observed  under  the  lens  as  a  series 
of  ripples  or  waves,  commencing  just  behind  the  head  and  continuing 
the  entire  length  of  the  body, — one  \vave  being  completed  or  spent, 
before  the  following  one  sets  in.  It  grows  rapidly,  but  very  steadily, 
increasing  each  day  in  the  same  ratio  until  the  last  twenty-four  hours 
of  feeding,  when  it  gains  somewhat  less  than  during  the  previous  days. 


30  INSECT  BEHAVIOR 

In  all,  the  larva  or  grub  is  full  grown  in  four  days  from  the  time  it 
hatches. 

Upon  finishing  its  meal,  which  lasts  continuously  for  four  days,  the 
larva  spins  a  flimsy  net  work  of  silken  threads  inside  of  which  the 
cocoon  proper  is  spun.  This  inner  cocoon  resembles  a  tiny  torpedo, 
rounded  at  both  ends  and  ten  millimeters  in  length.  It  is  very  neatly 
constructed  of  delicate  silk  and  coated  all  over  the  interior  with  a 
brown  varnish  that  hardens  in  contact  with  the  air. 

Within  this  delicate  cradle,  ten  days  later,  the  budding  wasp  under- 
goes pupation — that  wonderful  process  described  more  fully  in  the 
following  chapter — by  which  the  footless  grub  is  transformed  from  a 
low  and  ancient  form,  to  the  highest  order  of  modern  insects.  The 
actual  change  from  gorged  grub  to  a  neatly  folded,  but  colorless  wasp 
is  affected  in  ten  days,  but  it  still  has  three  hundred  and  twenty-eight 
hours  of  confinement  separating  it  from  the  light  of  day,  hours  which 
must  be  passed  quietly,  lest  injury  result. 

As  the  hours  go  by,  color  at  length  flows  through  its  body  and 
appendages,  transforming  opaque  yellow  to  glistening  black.  Then 
comes  the  final  gift  of  nature,  the  power  of  motion.  The  nascent 
creature,  moist  with  birth,  bursts  its  cocoon,  gnaws  through  the  plug 
of  mortar  and  issues  into  the  outer  world  a  perfect  insect.  Only 
thirty-eight  days  have  passed  since  I  placed  the  tubes  in  the 
laboratory,  and  since  the  parents  of  this  new  creature  arrived,  real- 
izing their  destiny. 

There  is  an  interesting  problem  to  solve  concerning  the  black  reed- 
wasps.  Their  nests  vary  considerably  in  number  of  cells.  Some 
are  complete  with  one,  others  contain  two,  but  the  majority  are  com- 
plete only  after  an  egg  has  been  laid  upon  the  stores  in  three  separate 
compartments.  The  question  arises,  How  will  the  wasps  emerge 
as  perfect  insects  without  disturbing  one  another? 

If  the  nest  is  to  shelter  three  insects,  the  cell  farthest  from  the 


Plough  furrows  are  as  mountain  ranges  to  the  insects 


'Above  the  dead,  fallen  stems  that  cover  this  tomh-life,  a  second  group  of  living  things  is  encountered" 
A  greatly  enlarged  hemipterous  insect 


THE  BLACK  REED-WASP  31 

entrance  will  naturally  receive  the  first  provisions  collected,  and,  it 
would  seem,  in  due  time,  the  first  egg  deposited.  The  remaining 
two  cells  would  receive  their  respective  contents  in  the  order  of  their 
position,  but  the  first  egg  laid,  naturally  hatches  before  the  others. 
The  grub  reaches  maturity,  pupates  and  is  ready  to  emerge  some- 
time ahead  of  its  sisters  in  the  other  cells.  What  happens  then?  Does 
the  issuing  wasp  burrow  its  way  out  through  the  cells  in  front,  up- 
setting in  its  passage  the  vital  conditions  of  solitude  that  surround  the 
younger  insects?  Does  it  burrow  through  the  clay  plugs,  separating 
each  nursery,  and  as  a  final  act  of  vandalism,  leave  the  nest  open, 
exposing  its  younger  sisters  to  the  first  parasite? 

So  it  would  seem,  but  such  a  course  would  be  contrary  to  all  the 
laws  of  nature.  She  does  not  destroy  her  children  needlessly,  yet  I 
wonder  what  happens  in  such  nests  as  that  of  the  black  reed-wasp, 
whose  oldest  child  seems  farthest  from  the  door  to  freedom! 

Perhaps  the  parent  wasp  is  gifted  with  the  power  of  laying  eggs 
that  require  varied  terms  of  incubation.  In  the  first  cell  provisioned 
she  lays  an  egg  that  requires  three  days  to  hatch,  in  the  middle  cell 
one  that  requires  two  days  and  in  the  outer  cell  the  egg  hatches  in  a 
day  and  a  half.  The  theory  would  straighten  out  the  difficulty 
very  nicely.  The  insects  would  emerge  in  turn  without  disturbing 
one  another  and  all  would  be  well,  but  a  theory  is  no  better  than  a 
guess.  Moreover  a  little  careful  observation  of  the  glass  tubes  yields 
the  correct  and  simple  answer  to  the  question. 

I  watch  a  wasp  entering  one  of  the  tubes  carrying  a  spider  which 
is  held  tightly  beneath  her  body.  She  enters,  stores  the  game, 
squeaks  about  it  to  her  watching  mate,  and  is  off  again  in  search  of 
a  second  victim.  She  does  not  rest  after  placing  eight  spiders  in  the 
tube,  yet  this  is  the  maximum  number  for  a  single  cell.  Instead, 
the  work  continues  during  most  of  the  day  without  interruption. 

In  the  afternoon  I  open  the  box  containing  her  nest.     The  tube 


32  INSECT  BEHAVIOR 

contains  twenty  spiders  separated  into  three  little  groups  by  half 
partitions  of  clay.  Upon  the  abdomen  of  a  large  spider  in  each 
group  she  has  deposited  an  egg.  Now  I  close  the  box  and  await  her 
return.  She  arrives  laden  with  a  tiny  ball  of  clay  in  her  mandibles, 
enters  the  nest  for  a  moment  and  then  flies  off  minus  her  burden. 

At  the  end  of  an  hour  the  operation  has  been  repeated  twenty 
times.  Now  she  commences  to  close  the  entrance  with  the  same 
material.  The  job  requires  ten  more  loads  of  mortar,  but  it  is 
completed  rapidly.  By  evening  she  has  left  the  nest,  I  presume 
for  good  and  all,  and  for  the  last  time  I  pry  into  her  secrets. 

It  is  all  very  clear.  In  a  single  day  she  has  accumulated  the 
entire  amount  of  provisions  necessary  to  provide  her  three  off- 
spring, and  separated  them  into  distinct  groups.  Further  she  has 
constructed  half  partitions  that  keep  the  stores  separate,  but  still 
permit  her  to  pass  from  one  end  of  the  nest  to  the  other.  Thus  she  is 
enabled  to  deposit  her  three  eggs  in  different  departments  of  the 
nest,  all  on  the  same  day.  The  laying  over,  she  has  only  to  finish 
the  half  partitions  with  a  few  loads  of  clay,  plug  the  entrance  and 
her  work  is  completed. 

She  deposited  all  her  eggs  within  an  hour  and  they  are  safe  in 
isolated  cells.  The  three  will  pass  through  their  metamorphosis  or 
life  history,  as  one.  They  will  eat  and  grow  and  pupate  together, 
and  issue  into  the  world  almost  at  the  same  moment.  Thus  the  black 
reed-wasp  solves  the  problem  very  simply.  She  brings  her  offspring 
into  the  world  as  triplets! 


Male  black  reed-wasp  guarding 
nesting  tube 


Female  black  reed-wasp  arriv- 
ing at  the  tube 


Glass  tube  removed  from  box, 

showing    plugs,    egg,    and 

spiders 


An  old  nest  of  a  jungle  mud-wasp,  the  empty  cells  of  which  were  used  as  nurseries  by  the  black  reed-wasp 


CHAPTER  III 

LARVAL   SACRIFICE 

IT  is  strange  what  a  vast  array  of  facts  are  disclosed  through  the 
study  of  the  unintelligent  invertebrate.     I  am  thinking  particu- 
larly of  insects,  dominant  creatures  of  the  earth,  into  whose  life- 
secrets  and  lore  man,  through  his  wretched  span  of  years,  may 
scarce  become  a  trespasser.     They  are  set  apart,  almost  in  another 
world,  vastly  wise  and  ruled  by  an  iron  discipline  that  has  wrought 
their  world  empire  of  today.     My  attitude  toward  the  insect  is  that 
of  a  pupil  under  a  great  master,  who,  unable  ever  to  reach  the  altitude 
of  his  mind,  must  be  content  to  set  forth  his  simplest  teachings.     No 
matter  where  I  look,  my  master  is  there,  a  superior  being  who  appears 
to  have  risen  far  above  me.     From  his  instinctive  throne,  he  looks 
down  pityingly  upon  my  intelligence,  I  who  must  put  two  and  two 
together  and  work  my  poor  brain  so  hard  to  understand  his  simplest 
problem. 

Words  fail  to  tell  adequately  of  what  I  see  in  the  world  of  insects. 
Then  again  there  is  much  that  I  fail  to  understand  anyway,  as  a 
consolation  for  the  missing  words,  but  occasionally  I  have  just  a  faint 
glimmer  of  what  is  transpiring  before  my  eyes.  Thus  I  shall  skip 
briefly  over  the  life  history  of  a  wasp  I  call  the  roach-killer.  Podium 
rufipes  (Fabr.),  to  the  subject  of  this  chapter. 

The  roach-killer  is  a  solitary  mason  wasp,  who  has  taken  advantage 
of  man's  intrusion  into  her  domain.  His  houses  and  buildings  afford 
safer  quarters  for  her  nest,  which  originally  she  cemented  to  the  con- 
cave sides  of  stumps  or  forest  trees.  Now  she  has  partly  abandoned 
the  old  sites  for  the  immovable  wooden  shutters  of  tropical  civiliza- 

33 


34  INSECT  BEHAVIOR 

tion,  where  her  rough  red  columns  of  clay  stand  for  years  as  monu- 
ments over  the  birth  beds  of  her  offspring. 

The  nest,  a  single  column  of  clay,  two  and  one-half  to  four  inches 
in  length  and  close  to  three-quarters  of  an  inch  in  diameter,  consists 
of  a  series  of  V-shaped  layers  placed  side  by  side.  The  entrance 
to  the  nursery  faces  toward  the  ground.  Inside  it  is  divided  into 
several  ten  by  twenty  millimeter  cells,  never  exceeding  four  in  num- 
ber, which,  compared  with  the  exterior,  are  quite  smooth  and  pol- 
ished. 

Here  is  an  interesting  fact;  if  the  wasp  has  chosen  her  original 
habitat  among  the  stumps,  she  abandons  it  when  finished  as  an  incon- 
spicuous gray  blotch  that  blends  nicely  with  its  surroundings.  In  the 
forest  she  finds  no  red  or  orange  clay  for  building  material.  The 
swamps  yield  a  rich  brown  and  the  brook  banks  a  shade  of  gray. 
The  nest  is  of  necessity  somber  in  color.  On  the  other  hand,  the 
nests  placed  in  the  shutters  of  houses  were  all  of  rich,  orange-red 
clay,  collected  from  a  nearby  excavation  in  the  trail.  They  were 
conspicuous  objects  to  say  the  least,  but  the  wasp  quickly  covered  her 
fresh  paint  with  a  neatly  arranged  layer  of  termite's  wings,  cast  off 
spider's  skins  and  other  bits  of  refuse.  At  first  I  put  the  occurrence 
down  as  accidental,  but  careful  examination  leads  me  to  believe  that 
it  is  a  regular  habit  of  the  wasp,  in  view  of  the  fact  that  not  a  square 
millimeter  of  the  underlying  clay  showed  through  the  veil.  When^ 
the  nests  were  finished  they  appeared  old  and  disused. 

Each  cell  is  usually  provisioned  with  four  wood  roaches.  Upon 
the  last  one  placed  in  the  cell  a  single  white  egg,  with  a  yellow 
median  line,  is  deposited.  It  is  thrust  under  the  fore  leg  of  the 
roach,  where  the  leg  joins  the  insect's  body.  It  is  a  tender  spot  where 
the  young  wasp,  two  days  later,  may  easily  bury  its  head  in  the 
creature's  flesh.  The  number  of  roaches  in  a  cell  varies  according 
to  their  aggregate.  Thus  a  cell  may  contain  two  medium  and  one 


Stages  in  the  larval  sacrifice,  showing  gradual  changes  from  larva  to  pupa.     (Life  size) 


Pupa  of  the  roach-killer  just  after  transformation  from  the  larva.     Greatly 

enlarged 


LARVAL  SACRIFICE  35 

very  large  insect,  or  six  small  ones,  and  while  there  is  variation 
in  the  number  of  victims,  the  total  bulk  and  food  value  of  each  cell's 
contents  remain  the  same. 

Two  days  after  the  egg  is  deposited  and  the  cell  sealed  up  \vith 
clay,  the  young  roach-killer  hatches.  It  is  but  a  tiny  grub  of  thirteen 
segments,  two  millimeters  in  length,  rather  transparent  and  concerned 
only  with  its  mouth  and  digestive  tract.  For  two  days  it  gorges, 
selecting  only  the  tenderest,  juiciest  parts  of  its  victims,  leaving  the 
legs  and  other  less  nutritious  parts  untouched.  On  the  fifth  day  of 
its  existence,  it  returns  to  these  left-overs,  going  over  and  over  them 
until  all  nourishment  is  gone. 

One  hears  the  glutton  plainly  at  its  feast.  Sip-sip-sip,  comes 
the  rhythmic  sound.  Its  entire  body  throbs  in  unison  as  the  greedy 
creature  dives  deeper  and  deeper  into  the  grab-bag  of  the  roach's 
anatomy.  In  five  days  the  feast  is  over.  The  wings,  egg  cases,  shells 
of  the  heads  and  thorax,  together  with  the  hard  limb  skeletons  of  the 
roaches  are  left  uneaten  in  the  end.  They  lie  about  the  cell  in  fine 
disorder  as  lasting  evidence  of  the  grub's  revelry. 

Immediately  upon  finishing  the  repast,  the  larva  constructs  a  net- 
work of  silken  threads,  just  enough  to  prevent  its  rolling  about. 
Within  this  cradle,  an  inner  cocoon  is  formed,  composed  of  threads 
much  more  densely  spun,  and  finally  coated  within,  with  a  reddish 
brown  fluid  that  hardens  in  contact  with  the  air,  into  a  brittle  skin. 
The  process  of  spinning  and  coating  requires  eighteen  hours  for  com- 
pletion, after  which  the  larva  excretes  the  waste  from  its  five-day 
gorge  in  a  single  mass  at  one  end  of  the  cocoon. 

Spinning  over,  there  comes  a  ten-day  pause  in  the  creature's  activ- 
ity, during  which  time  we  shall  witness  the  Larval  Sacrifice.  This 
process,  known  as  pupation,  is  in  many  respects  the  strangest  and 
most  wonderful  of  all  physiological  transformations  that  take  place 
in  the  insect  world.  We  will  see  the  grub,  which  in  reality  is  but 


36  INSECT  BEHAVIOR 

the  ancestral  form  of  the  wasp,  transformed  by  what  we  might  call 
a  "second  birth,"  from  its  lowly  worm-like  body  into  an  utterly 
different  and  highly  specialized  member  of  the  topmost  order  of 
modern  insects. 

We  have  traced  the  larva  from  the  time  the  parent  wasp  deposited 
it  as  a  tiny  egg  upon  the  roach's  body.  We  have  watched  its  growth 
from  day  to  day  and  observed  how  it  tackles  one  victim,  consumes 
it,  searches  out  a  second,  then  a  third  and  fourth:  how  it  eats  the 
tender  portions  first  and  returns  later  to  coarser  fare.  Its  actions  are 
almost  those  of  a  creature  conscious  of  its  life  and  appetite,  which 
thinks  only  of  its  stomach  and  so  many  good  things  to  be  consumed. 
But  the  minute  the  repast  is  over,  and  the  cocoon  spun,  we  see  this 
energetic  and  ravenous  bit  of  life  cease  all  outward  activities. 

From  young  to  full-grown  larva,  the  creature  is,  in  a  measure, 
master  of  itself.  It  moves  about  in  the  cell  of  its  own  accord,  feeds 
itself  copiously  and  rests  if  need  be,  but  thereafter  it  must  surrender 
to  an  incomprehensible  power,  an  invisible  surgeon  who  will  anes- 
thetize the  grub,  tear  down  its  old  body  and  bring  forth  a  new  and 
better  creature  from  the  havoc  of  his  scalpel. 

During  the  operation,  many  of  the  larval  organs  and  tissues  are 
entirely  done  away  with,  and  at  the  same  time  many  parts  of  the  new 
insect  are  derived  from  them.  There  is  no  spilling  of  blood,  no 
suffering,  no  consciousness  of  what  is  taking  place  within  the  larval 
skin.  From  the  exterior  we  see  nothing  to  hint  of  what  is  transpiring. 
All  is  serene  during  the  ten  days  that  the  operation  requires  for  com- 
pletion. 

This  strange  process  of  "second  birth"  (I  have  no  adequate  term 
for  it),  is  unknown  in  creatures  other  than  insects.  From  the  blood 
and  tissues  of  the  horse,  the  foetus  is  produced,  and  eventually  born. 
It  arrives  quite  like  the  parent  except  for  minor  details.  Without 
radical  changes  it  feeds,  lives  and  grows  to  maturity.  In  the 


LARVAL  SACRIFICE  37 

chicken  we  have  the  egg,  then  the  young,  different  at  birth  from  the 
parent,  but  rapidly  growing  to  resemble  it,  upon  the  addition  of 
food  .to  the  youngster's  stomach.  In  the  wasp  we  have  an  egg, 
followed  by  a  grub  that  is  unable,  simply  by  eating,  to  become  like 
its  parent.  Something  more  radical  is  necessary,  a  complicated  bit 
of  surgery  which  will  knock  down  the  larval  house  and  raise  an  imago 
from  the  ruins! 

Thus  in  ten  days  after  the  larva  spins  its  cocoon  we  see  a  slight 
shrinking  of  the  body.  A  depression  just  off  center  follows.  There 
is  a  tremor,  ever  so  slight,  then  slowly  the  whole  perfect  insect  un- 
folds from  the  grub  like  a  nascent  flower  from  its  bud.  It  may  re- 
quire a  million  years  for  processes  of  evolution  to  become  established 
into  a  train  of  events,  yet  here  in  the  course  of  a  few  days,  by  watch- 
ing this  wonderful  transformation  from  grub  to  pupa,  wre  have 
actually  witnessed  the  ancestral  form  sacrificing  itself  to  a  modern 
one! 

The  processes  that  bring  about  such  radical  changes  in  the  insect 
are  known  as  histolysis  and  histogenesis.  The  former  covers  the 
breaking  down  and  disintegration  of  the  larval  tissues  and  the  latter 
the  building  of  the  new  body,  in  part  independent  of  the  old  material. 
There  is  little  known  of  these  strange  performances,  yet  it  appears 
to  be  the  general  belief  that  for  the  most  part  the  perfect  insect  is 
developed  chiefly  from  the  skin  cells  of  the  larva.  Therefore,  I  shall 
set  forth  what  I  have  been  able  to  gather  through  the  logic  of  observa- 
tion, about  this  point.  I  make  my  statements  guardedly — simply  as 
facts  that  appear  to  have  been  overlooked. 

A  yacht  is  built  and  launched.  She  serves  admirably  as  a  pleasure 
craft  and  is  quite  satisfactory  for  that  purpose.  War  is  declared. 
She  is  commandeered  by  the  government  for  patrol  duty  and  must 
be  altered  to  meet  new  requirements.  She  is  dry-docked,  fitted  with 
guns,  more  powerful  engines  are  installed,  and  lastly  she  is  painted 


38  INSECT  BEHAVIOR 

the  battle  color.  Later  the  craft  appears  once  more  upon  the  water. 
Altered  tremendously,  the  old  hulk  still  serves  the  fundamental  pur- 
pose. It  is  much  the  same  with  the  insect.  The  larval  wasp  is 
commandeered  by  nature.  She  must  be  fitted  to  meet  new  conditions 
in  order  to  perpetuate  her  race.  Thus  the  task  devolves  upon  his- 
tolysis,  the  wrecker,  and  histogenesis,  the  builder. 

During  the  period  of  larval  growth,  from  the  time  it  hatches 
until  the  provisions  in  the  cell  are  entirely  consumed,  the  grub  rids 
itself  of  no  waste  matter  whatever.  Unlike  the  larva  of  the  butterfly 
that  excretes  every  few  minutes  as  it  eats  during  the  days  of  its  worm 
life,  the  young  wasp  waits  until  its  stores  are  gone  and  its  cocoon 
spun  before  passing  off  the  waste  of  its  five-day  gorge.  Even  then  it 
waits  another  day  before  finally  depositing  it  in  a  single  mass  at  the 
lower  pole  of  the  cocoon.  A  few  days  later  pupation  takes  place. 

In  the  days  which  pass,  between  excretion  and  pupation,  no  foreign 
matter  appears  within  the  cocoon.  The  insect  is  motionless:  its 
cradle,  save  for  the  hardened  mass  at  one  end,  is  scrupulously  clean. 
I  remove  this  mass,  float  it  out  in  a  little  water  and  subject  it  to  a 
thorough  inspection  under  the  microscope.  It  contains  bits  of  chitin, 
hairs  and  fragments  of  claws,  all,  however,  fragments  of  the  deceased 
roaches.  There  is  nothing  unusual  in  the  array,  no  bits  of  larval 
anatomy,  no  fragments  of  the  grub  itself.  What  then  becomes  of  the 
material  that  histolysis  is  supposed  to  dispoil?  Are  the  skin  cells  all 
of  the  grub's  anatomy  that  serve  to  build  the  wasp? 

I  cut  open  the  body  of  a  grub,  three  days  after  the  cocoon  is  spun. 
The  greater  part  of  it  runs  through  the  incision  as  a  smooth,  pasty 
liquid,  amorphous  in  every  way.  At  eight  days,  I  open  a  second 
grub.  Now  it  is  partly  paste,  but  mostly  wasp ! 

The  laborers  of  histolysis  are  not  altogether  wreckers  then.  They 
are  concerned  more  with  tearing  down  the  old  timbers,  removing  the 
rusty  nails,  puttying  the  holes  and  handing  them  back  to  the  equally 


LARVAL  SACRIFICE  39 

skillful  employees  of  histogenesis,  who  in  turn  rebuild  the  house 
along  more  modern  lines. 

Twenty-four  days  after  pupation  the  insect  issues  from  the  cocoon, 
drills  a  neat  hole  through  the  wall  of  its  nursery  and  emerges  into 
the  sunlight  a  perfect  insect.  Behind  her,  she  leaves  a  few,  very  tiny 
pellets  of  white  excreta.  These  are  the  rusty  nails  from  the  old 
structure.  They  are  all  I  can  find  of  the  larval  body  that  is  not 
incorporated  in  the  new. 

Fruit  from  the  tree  of  instinctive  wasp-love,  the  newborn  insect 
is  only  an  atom  in  the  world,  but  what  a  bundle  of  unsolved  mysteries 
to  the  humble  student  of  her  secrets!  At  her  "second  birth,"  she 
becomes  her  own  mother !  Not  content  with  skin  cells  alone  as  build- 
ing material,  histolysis  and  histogenesis  have  rebuilt  the  Huntress 
from  herself.  She  flies  into  the  world  with  a  fresh  coat  of  paint, 
remodeled,  a  thing  brought  up  to  date,  but  somewhere  underneath, 
lie  the  old  timbers,  reshaped  and  sawn  to  meet  the  new  plan! 


CHAPTER  IV 

THE  WHITE-FOOTED  WASP 

Trypoxylon  leucotrichium,  Rohmer 

AN  alert  business-like  insect,  deep  steel  blue  with  a  white 
band  encircling  each  of  her  hind  tarsi,  the  white-footed 
wasp  is  readily  recognized.     She  inhabits  the  hot  open 
trails  where  bamboo  grass  has  been  slashed  in  clearing, 
leaving  here  and  there  a  severed  hollow  stem  hanging  in  mid-air  and 
supported  by  the  plant's  shriveled  leaves,  which  catch  among  other 
foliage.     These  hollow  tubes  supply  the  insect's  favorite  nesting  sites, 
unapproachable  from  below  except  by  winged  enemies. 

The  reed  which  the  wasp  had  chosen  had  been  severed  by  a  knife 
slash  so  that  its  end  was  sliced  off  at  a  gentle  angle-.  It  hung  four 
feet  above  the  ground  in  a  heavy  patch  of  bamboo  grass  with  its 
open  end  pointing  toward  the  earth.  Several  other  open  reeds  of 
the  same  character  surrounded  it,  appearing  to  me  very  much  the 
same.  Not  so  to  the  wasp,  however,  she  differentiated  at  once,  and 
upon  returning  from  her  journeys,  flew  directly  to  the  reed  of  her 
choice.  There  was  no  uncertainty  in  her  approach,  no  repeated 
trials  to  find  the  proper  entrance.  A  straight,  single  flight  from  the 
outer  world  to  her  tube  marked  her  arrival.  What  a  contrast  to  the 
clumsy  one-banded  dauber  who  wastes  her  precious  time! 

I  first  found  the  white-footed  wasp  gathering  a  ball  of  soggy  clay 
in  a  pitfall  trap  in  the  trail  leading  to  the  forest.  Several  of  these 
holes  had  been  excavated  and  for  their  intended  purpose  of  catching 

frogs,  toads  and  the  smaller  rodents  they  were  perhaps  less  produc- 

40 


Species  of  spider  used  as  provender  by  the 
white-footed  wasp. 


Nesting  reed  of  white-footed  wasp  opened  to  show 
elaborate  cocoon. 


Tangle  of  reeds  and 


razor  grass  in  British  Guiana.     In  the  ends  of  these  reeds,when  cut  or  broken,  the  white- 
footed  wasp  makes  her  nest. 


THE  WHITE-FOOTED  WASP  41 

tive  than  they  were  of  wasps.  The  pits,  after  a  rainfall,  often  con- 
tained several  inches  of  water.  When  bailed  out,  a  pasty  layer  of  clay 
would  be  left  in  the  bottom  of  each.  This  material,  a  ready  made 
mortar,  proved  attractive  to  a  number  of  wasps,  which  used  mud 
in  the  construction  of  their  nests.  Tiny  little  reed-wasps,  medium- 
sized  ones,  big  blue  huntresses,  daubers  and  a  dozen  others  collected 
at  this  abundant  public  property.  Here,  side  by  side,  they  gathered 
their  building  material,  all  laboring  in  a  great  common  design  for 
the  welfare  of  their  race  in  the  future. 

The  wasp  brought  several  loads  to  her  tube,  scraping  it  up  from 
the  floor  of  the  pitfall  and  carrying  in  it  little  globules  to  her  door- 
way. Once  within,  a  high-keyed  squeaking  and  buzzing  would  con- 
tinue until  the  clay  was  thoroughly  kneaded  into  a  safety  plug 
at  the  upper  end  of  the  reed.  Her  trips  between  nest  and  pit  were 
continued  for  nearly  an  hour,  like  a  hod-carrier  laboriously  plying 
between  mortar  box  and  masonry.  After  many  trips  back  and  forth 
she  disappeared,  returning  in  a  little  less  than  half  and  hour  with 
a  limp,  paralyzed  spider. 

The  victim,  a  medium-sized  creature,  was  richly  colored  and 
patterned  in  various  shades  of  brown.  Its  body  was  quite  small, 
measuring  six  millimeters  in  width,  but  the  legs,  all  of  which  were 
intact,  were  long  and  rather  cumbersome  to  the  wasp.  With  her 
burden  she  flew  directly  to  the  entrance  of  her  nest.  She  alighted 
with  difficulty,  then  turning  about  and  grasping  the  spider  by  one 
of  its  palpi  she  endeavored  to  enter  the  reed  backwards.  All  went 
well  for  a  time.  The  victim's  cephalothorax  and  fore  legs  caused 
no  trouble,  but  its  abdomen  caught  at  once  upon  the  sharp  edge  of 
the  reed,  which  tapered  almost  to  a  point.  From  this  point  the 
spider  would  not  budge — and  what  is  more,  was  in  great  danger 
of  being  punctured.  Had  the  wasp  pulled  too  hard  it  certainly 
would  have  been  impaled  on  the  reed  and  ruined  for  future  use. 


42  INSECT  BEHAVIOR 

Here  I  witnessed  a  most  skillful  performance.  Clinging  to  the  in- 
terior of  the  reed  with  only  her  two  posterior  claws,  the  wasp  lowered 
the  spider  very  carefully  and  deliberately  until  its  entire  body 
swung  free  in  the  air.  Here,  clasped  tightly  in  the  wasp's  strong 
mandibles,  it  was  held  by  its  two  front  legs,  and  rotated,  so  that  its 
abdomen  came  into  the  position  so  lately  held  by  the  cephalothorax. 
Then  walking  backward  up  the  tube  the  wasp  succeeded  in  bearing 
her  victim  to  its  last  resting  place. 

As  I  have  already  stated,  the  wasp  seeks  out  spiders  which,  al- 
though of  moderate  size,  possess  long,  slender  legs,  and  there  is  a  sim- 
ple significance  in  her  choice.  The  wasp's  nest  is  a  hollow  reed  whose 
smooth  perpendicular  walls  end  abruptly  in  space.  Her  front  door 
gapes  in  the  void  and  must  be  approached  from  below.  The  spider's 
body  alone  is  considerably  smaller  than  the  diameter  of  the  tube. 
Thus  were  the  wasp  to  choose  a  short-legged  victim  it  would  drop 
from  the  nest  at  the  instant  of  release.  The  long  legs  of  her  spider 
are  doubtless  burdensome,  yet  they  are  a  necessity  to  the  success  of 
her  work.  In  drawing  them  into  the  reed,  their  legs  fold  back  be- 
tween abdomen  and  reed,  filling  the  intervening  space  so  nicely  that 
the  entire  creature  remains  wherever  the  wasp  places  it. 

Four  of  these  spiders  are  allotted  to  each  of  the  three  cells,  which 
are  separated  as  the  wasp  provisions  them,  with  plugs  of  clay  three 
millimeters  in  thickness.  Upon  the  side  of  the  largest  spider  in  each 
cell,  a  three-millimeter  egg  is  deposited.  It  is  slightly  bowed,  just 
enough  to  fit  the  curve  of  the  spider's  abdomen,  slightly  elongated 
at  one  end  and  about  the  color  of  skimmed  milk. 

The  three  cells  vary  considerably  in  size.  One  measures  three 
inches,  another  two,  and  the  third  is  an  inch  and  three-quarters  long. 
For  these  differences  I  can  see  no  reason.  So  long  as  there  are  three 
cells  in  the  tube  the  wasp  is  apparently  quite  satisfied  to  place  her 
divisions  at  random. 


THE  WHITE-FOOTED  WASP  43 

The  egg  hatches  in  forty-eight  hours,  resulting  in  the  character- 
istic wasp  grub  of  thirteen  segments.  It  commences  feeding  at  once 
upon  the  stored  spiders,  first  drawing  off  the  soft  parts,  and  later 
returning  to  less  delicate  food.  During  the  first  day  of  its  life  the 
larva  grows  only  two  millimeters.  On  the  second  and  third  days  it 
averages  five  millimeters  each.  On  the  fourth  day  it  goes  back  to 
two,  grows  eight  on  the  fifth  and  finishes  with  a  growth  of  one  milli- 
meter on  the  sixth  and  last  day  of  its  meal.  The  spiders  are  now 
entirely  consumed  and  the  grub  measures  twenty-six  millimeters  in 
length. 

Without  pausing  for  a  moment  to  rest,  the  full-grown  larva  now 
sets  about  to  lay  the  foundations  of  its  elaborate  cocoon.  The  insect 
is  awkwardly  placed  at  the  outset,  living  as  it  does  in  a  cell  whose 
perpendicular  walls  are  several  times  its  own  length,  but  fortunately 
at  this  period  of  its  life  it  is  endowed  with  an  unusually  tacky  skin. 
This  stickiness  serves  a  special  purpose,  enabling  the  grub  to  remain 
safely  in  the  top  or  center  of  its  cell  without  the  slightest  danger  of 
tumbling  down  to  the  mortar  plug  separating  it  from  the  cell  below. 

From  its  lofty  position  and  in  total  darkness,  the  grub  first  throws 
out  several  bands  of  silk,  fastening  them  in  various  places  about  the 
reed  \valls.  It  makes  no  choice  of  its  own,  but  simply  fastens  each 
successive  thread  to  the  first  point  of  contact.  Some  of  the  strands 
pass  to  points  above  the  spinner,  some  below,  and  still  others  across 
the  middle  of  its  body  to  the  wall  beyond.  At  length  the  grub  finds 
itself  more  or  less  enclosed  in  a  delicate  silken  net  through  the  strands 
of  which  it  may  still  poke  its  head. 

Thirty  or  forty  new  threads  are  now  extended  from  the  top  of  the 
growing  cocoon.  They  emerge  from  various  points  in  a  circle,  and 
are  fastened  to  the  cell  wall  above.  The  larva  now  returns  to  its 
original  network,  within  which  it  spins  a  firm  torpedo-shaped  cover- 
ing, slightly  wider  than  its  own  body,  nineteen  millimeters  in  length 


44  INSECT  BEHAVIOR 

and  open  at  the  upper  end.  Through  this  opening  a  ring  of  silk  is 
spun,  two  millimeters  in  height,  with  a  scalloped  edge,  the  point  of 
each  scallop  forming  one  of  the  thirty  or  more  strands  extending 
above  the  cocoon.  The  open  top  is  now  closed  and  reinforced  with 
silk,  the  strands  crossing  and  recrossing  in  every  imaginable  direction 
so  that  the  cocoon  now  appears  in  the  shape  of  a  stubby  cigar  with 
an  inverted  parachute  at  one  end.  The  strings  of  the  parachute  ex- 
tend above,  where  they  are  fastened  to  the  reed,  thus  suspending  the 
entire  cradle  in  the  center  of  the  cell. 

The  cocoon  is  now  strongly  supported  from  above.  It  hangs  per- 
pendicularly in  the  hollow  reed,  head  up,  and  no  matter  how  the 
larva  thrashes  about,  there  is  no  danger  of  falling.  Two  or  three 
hours  after  the  last  silken  thread  has  been  spun,  the  grub  continues 
its  work,  this  time  coating  the  entire  inner  surface  of  its  cradle  with 
a  transparent  or  slightly  yellowish  fluid.  A  certain  amount  of  this 
is  brushed  directly  upon  the  walls  as  it  oozes  from  the  creature's 
mouth,  but  for  the  most  part,  the  grub  expectorates  it  upon  its  own 
ventral  surface.  From  here  it  is  caused  to  flow  over  its  entire  body 
by  a  strange  series  of  muscular  contractions.  The  operation  is  re- 
peated over  and  over  until  the  writhing  creature  is  thoroughly  moist- 
ened by  the  secretion.  As  the  grub  expands,  contracts  and  turns  its 
segments,  the  liquid  becomes  incorporated  with  the  silk  of  the  cocoon, 
wetting  it  thoroughly  on  the  outside. 

It  is  a  varnish  with  strange  properties  that  the  larva  employs, — 
a  sort  of  cement  which  will  adhere  only  to  certain  objects.  When 
secreted  it  is  transparent  or  nearly  so.  It  amalgamates  at  once  with 
the  silk  and  hardens  in  contact  with  the  air  into  a  skin,  purplish  brown 
in  color  and  brittle,  like  the  inner  covering  of  a  peanut.  Strange  to 
say  it  does  not  adhere  to  the  larva,  nor  turn  color  until  compounded 
with  the  other  material  of  which  the  cocoon  is  made. 

The  entire  process  of  spinning  and  varnishing  requires  two  full 


THE  WHITE-FOOTED  WASP  45 

days.  The  grub  then  expels  a  large  pellet  of  waste,  the  accumulation 
of  six  days  of  feeding,  in  the  bottom  of  the  cocoon.  This  hardens 
rapidly  into  a  solid  cake  in  a  few  hours.  Sixteen  days  later  pupation 
takes  place. 

Xow  comes  the  period  of  absolute  quiet  during  which  time  the 
insect  receives  its  color,  which  appears  first  in  the  eyes  and  gradually 
flows  throughout  the  body  and  its  appendages.  The  process  requires 
some  fifteen  days.  This  is  followed  by  a  six-day  period  before  the 
perfect  insect  emerges,  to  lay  the  cornerstone  of  a  new  generation. 


CHAPTER  V 

PARALYZED  PROVENDER 

IN  the  black  chambers  of  a  solitary  wasp's  nest  lie  six  growing 
youngsters.    They  are  grayish,  maggot-like  creatures,  each  con- 
sisting of  twelve  rings  or  segments  surmounted  by  a  more  or 
less  bony  or  chitinous  head  that  in  turn  supports  a  pair  of  sharp 
incurved  mandibles.     Their  bodies   are   plump   and   pudgy;   they 
possess  no  adequate  appendages  for  locomotion  and  in  the  light  their 
skins  glisten,  as  if  moistened  with  liquid. 

Each  will  eventually  become  a  wasp,  an  active  dominant  creature 
with  a  delicate  taste  for  nectar.  But  that  is  far  off  in  the  insect 
future,  perhaps  some  forty  days  hence.  They  are  concerned  now 
only  with  the  meals  that  are  set  before  them,  spiders  that  the  parent 
wasp  has  selected  as  dainty  provender. 

In  each  cell  of  the  nest  the  mother  insect  deposits  her  bowed  egg 
among  the  mass  of  spiders  that  are  paralyzed  by  her  sting.  She 
hunts  them  abroad  in  the  forest  or  among  the  fallen  leaves  in  the 
sunny  trails,  discovers  their  hiding-place  and  swoops  hawk-like  upon 
the  unfortunates.  There  is  a  struggle,  perhaps,  a  short  one;  the 
wasp's  sting  soon  finds  its  mark,  plunges  home,  and  in  an  instant  the 
spider  lies  limply  upon  its  threshold.  The  victim  is  not  dead,  in- 
stead it  is  only  plunged  into  a  state  of  paralysis  that  instantly  binds 
the  muscles  fast.  It  cannot  move  again  in  self-defense,  cannot  com- 
mand the  power  of  its  legs.  It  is  still  a  living  thing  unconscious 
of  life.  Thus,  slightly  quivering  from  the  shock  and  poison,  it  is 
borne  to  the  victor's  nest,  deposited  roughly  in  a  cell  with  several 

other  equally  unfortunate  ones,  sealed  forever  from  the  light  of  day 

46 


PARALYZED  PROVENDER  47 

and  abandoned  as  helpless  living  flesh  for  the  young  wasp  to  gorge 
upon, 

In  order  to  understand  what  has  just  taken  place,  let  us  examine 
the  victim's  anatomy  and  structure.  In  outward  form  spiders  are 
divided  into  two  distinct  parts — the  cephalothorax  and  the  abdo- 
men. We  are  concerned  chiefly  with  the  former,  which  is  the  first 
division  of  the  creature,  the  head  and  thorax,  as  it  were,  combined 
in  one.  The  central  nervous  system  of  the  spider  is,  for  the  most 
part  concentrated  in  a  mass  of  ganglions  clustered  about  the  oesoph- 
agus. The  oesophagus  is  a  tube  through  which  food  passes  from 
the  mouth  to  the  stomach.  It  lies  in  the  central  portion  of  the 
cephalothorax.  That  part  of  the  central  system  lying  above  is  the 
brain,  from  which  the  optic  nerves  and  those  of  the  biting  and 
poisoning  appendages  arise.  Lying  below  the  oesophagus  is  the 
ganglion  from  which  the  nerves  of  the  legs  and  palpi  emerge. 

Now,  strange  as  it  may  seem,  the  wasp  knows  the  above  paragraph 
by  heart.  She  was  an  anatomist  long  before  man.  She  understood 
spiders  long  before  man  understood  himself.  Her  teacher  was  in- 
stinct, an  immortal  master.  Thus  in  stinging  her  spider  she  is  like 
the  master  surgeon.  With  a  single  tiny  wound  above,  with  a  single 
lance  below,  she  accomplishes  the  desired  end.  Into  the  spider's 
nervous  center  instinct  guides  the  wasp's  poisoned  dart.  With 
precise  strokes  she  reaches  the  ganglions  of  her  victim  and  spills 
.  her  venom.  Henceforth  no  external  outrage,  however  great,  may  be 
transmitted  to  the  brain;  no  volition  in  return  will  command  the 
forces  of  protest  and  defense.  Like  a  party  on  a  broken  wire,  the 
spider  lies  helpless  with  the  central  office  paralyzed! 

In  preparing  provender  for  the  cells,  the  methods  employed  by  the 
majority  of  solitary  wasps  are  more  or  less  the  same.  Yet  the  sting- 
poisons  of  different  species  produce  two  widely  different  effects  on 
the  victims.  Both  are  doubtless  forms  o-f  the  same  affliction;  one, 


48  INSECT  BEHAVIOR 

the  commonest  type,  acts  instantly,  as  I  have  just  described.  It 
causes  complete  paralysis  throughout  the  muscles  that  control  walk- 
ing, biting,  excretion  and  all  exterior  movements  of  the  cephalo- 
thorax,  abdomen  and  its  appendages.  The  respiratory  system  ap- 
pears to  be  all  that  is  left  uninjured. 

The  second  form,  which  is  much  more  rarely  met  with,  is  a  gradual 
type,  commencing  with  the  deadening  effect  of  heavy  sleep,  finally 
giving  place  to  paralysis,  some  time  after  the  victim  is  stricken  by 
the  sting.  Let  us  observe  the  two  cases  in  question.  As  an  example 
of  the  first  we  have  a  medium-sized  spider  that  has  been  stung  by 
the  white-footed  wasp.  Of  course  different  kinds  of  spiders  are 
selected  by  different  species  of  wasps.  But  this  is  of  no  consequence, 
and  will  not  affect  the  essential  facts  of  our  observation.  If  the 
creature  is  a  spider  it  matters  not  in  the  least  whether  it  be  Gastera- 
cantha,  Filistata,  Micrathena  or  any  other  jaw-splitting  species. 
Spiders  are  the  common  prey  of  many  solitary  wasps,  a  fact  which 
is  sufficient. 

The  victim  lies  limply  upon  its  belly  in  the  cell.  Enclosed  in  a 
tomb  of  solid  masonry,  it  is  abandoned  by  the  mother  wasp  to  its  fate. 
Upon  its  flank  lies  the  glistening  egg  of  the  slayer.  Thus  the  un- 
conscious living  incubator  awaits  the  pleasure  of  the  maggot.  Its 
legs  are  limp  and  motionless,  its  palpi  equally  still.  To  all  intents 
and  purposes  the  dejected  object  is  dead,  but  there  is  still  a  flutter  of 
life  in  the  outraged  body.  An  occasional  shudder,  barely  discernible 
under  the  lens,  a  labored  rise  and  fall  of  the  abdominal  walls  evi- 
dences the  tiny  spark  still  unquenched. 

In  two  days  the  young  wasp  emerges  from  the  egg,  glues  its  mouth 
to  the  plump  spider  and  commences  to  draw  the  victim,  drop  by 
drop,  into  its  own  body.  In  twenty-four  hours  a  shriveling  sets  in. 
Like  a  punctured  balloon  in  the  sky,  the  spider  shrinks  before  the 
maggot's  onslaught.  Later,  in  order  to  taste  sweeter  fare,  the 


As  they  appear  at  close  range 

Two  common  bugs  which  do  great  damage  to  squash  and  pumpkin  vines.    Both  the  insects  shown  above  are 
immature,  the  lower  one  being  the  common  squash-bug  in  its  dotted  youthful  costume 

Enlarged  four  times 


PARALYZED  PROVENDER  49 

ravenous  object  plunges  its  head  within  the  breach.  It  drinks, 
munches  and  revels  in  the  spider's  anatomy;  eats  from  the  inside 
to  the  out,  chews  up  the  bony  walls,  continues  through  the  cephalo- 
thorax  and  finally  consumes  the  legs.  Then  finding  no  more  it 
pauses.  After  five  days  of  orgy  it  is  time  to  digest.  Thus  the  spider 
is  eaten  alive,  but  from  the  first  there  is  never  a  sign  of  protest,  never 
a  twinge  of  pain. 

As  an  experiment,  I  secured  several  other  spiders  paralyzed  by 
the  same  wasp  whose  j*rub  I  have  described  at  its  meal,  and  subjected 
them  to  various  tests.  One  I  denude  of  its  legs,  clipping  them  off 
at  different  lengths,  thereby  cutting  through  eight  different  nerves. 
From  the  second  I  clip  the  palpi,  severing  the  nerves,  and  into  the 
abdomen  of  the  third  I  thrust  a  slender  needle.  Throughout  these 
gross  indignities  the  spiders  lie  quite  motionless.  There  is  no  con- 
tracting of  leg  stumps,  no  drawing  in  of  injured  palpi,  no  quiver  of 
punctured  body.  There  is  no  response,  no  feeling  in  the  creatures. 

Such  is  the  first  condition  of  paralysis.  We  find  it  in  a  host  of 
victims.  The  white-footed  wasp,  the  blue  huntress,  the  black  reed- 
wasps  and  many  others  go  in  quest  of  the  spider,  another  wasp  takes 
frog-hoppers,  still  another,  locusts,  and  there  are  many  others  that  I 
will  not  mention.  They  are  a  merciful  crowd.  Under  the  re- 
spective jaws  of  their  grubs,  the  victims  lie  completely  paralyzed, 
relieved  from  the  tortures  of  gradual  execution. 

The  second  form  of  paralysis  is,  as  I  have  stated,  much  more  rarely 
met  with.  At  the  present  time  I  know  of  only  two  wasps  that  afflict 
their  prey  in  this  manner,  but  they  will  do  very  well  as  examples. 
One  is  the  roach-killer  (Chapter  III),  which  stores  her  earthen  cells 
with  wood-roaches,  the  other,  a  tiny,  unidentified  wrasp  that  supplies 
her  maggots  with  a  cricket  each.  Her  nest  is  a  hollow  reed  lying 
upon  the  ground,  the  end  of  which  she  plugs  with  a  great  quantity 
of  wood — little  chunks  of  charcoal  from  the  cane  burnings,  bits  of 


50  INSECT  BEHAVIOR 

reeds,  tiny  twigs  and  woodchips  barricade  her  doorway.  Therefore, 
for  convenience  sake,  I  will  call  her  the  lumberess. 

The  modes 'of  life  of  the  two  insects  are  in  most  respects  widely 
at  variance.  They  build  individual  types  of  nests,  provision  them 
differently,  choose  different  situations  for  the  home  site  and  go  about 
their  respective  businesses  in  separate  ways.  It  is  important,  how- 
ever, that  the  two  have  a  single  habit  in  common.  The  roach  victims 
of  one  and  the  cricket  prey  of  the  other  are  affected  in  the  same  man- 
ner by  the  stings  of  the  two  insects. 

I  have  before  me  two  crickets  of  the  lumberess  and  a  dozen  roaches 
of  the  roach-killer.  These  I  collected  from  the  sealed  nests  of  the 
insects.  Therefore,  to  the  best  of  my  knowledge  they  have  been 
stung  by  the  two  wasps.  I  find  in  the  victims  a  physical  condition 
entirely  different  from  that  existing  in  the  spiders  paralyzed  by  the 
white-footed  wasp.  So  differently  are  they  affected  that  I  do  not 
consider  them  paralyzed  at  all. 

The  roaches  are  capable  of  moving  every  pair  of  legs,  they  can 
turn  the  head  from  side  to  side,  also  move  all  the  mouth  parts  and 
their  antennae.  But  strange  to  say  they  lie  motionless  unless  I  touch 
them  with  a  needle  or  the  tip  of  my  pencil.  I  place  one  of  the  roaches 
upon  its  feet.  It  lies  absolutely  still  as  though  dead  until  I  touch 
one  of  the  protruding  appendages  at  the  posterior  end  of  its  body. 
As  I  do  so  it  jumps  forward  without  much  effort,  in  the  act,  using 
each  pair  of  legs.  Now  it  waves  its  antennae  back  and  forth  for  a 
few  seconds,  wriggles  its  mouth  and  settles  back  into  its  torpor.  With 
the  crickets  I  try  a  similar  experiment  with  the  same  result.  Much 
the  same  thing  appears  to  take  place  in  these  victims  as  one  observes 
in  a  sleeping  dog,  whose  foot  has  been  tickled  with  a  straw.  It  is 
quite  peaceful  and  unconscious,  yet  its  nerves  and  muscles  respond 
automatically  to  rid  the  animal  of  its  annoyer. 

Certainly  then,  the  insects  are  not  paralyzed  at  this  time,  any 


PARALYZED  PROVENDER  51 

more  than  a  sleeping  dog,  for  paralysis  means  the  loss  of  power 
to  contract  the  muscles,  an  accomplishment  of  which  both  the  roaches 
and  crickets  are  still  capable. 

Twenty-four  hours  later  I  experimented  again  upon  my  subjects 
with  a  result  similar  to  that  of  the  previous  day.  I  let  another  twenty- 
four  hours  pass.  This  time,  at  the  touch  of  my  pencil  point,  the 
insect  responded  with  a  jump  far  less  energetic  than  before.  Every 
hour  now  brings  a  weaker  reaction;  at  length  there  is  little  or  no 
response  to  my  efforts. 

The  sting  of  the  roach-killer  and  that  of  the  lumberess  thrust  their 
victims  into  painless  sleep.  The  poison's  action  is  not  unlike  alcohol. 
At  first  a  powerful  sleeping  potion  followed  by  a  gradual,  ever- 
increasing  tying  of  the  muscles,  until  they  cease  to  move  at  all.  Such 
is  the  second  condition  of  paralyzed  provender. 

Let  us  now  endeavor  to  discover  the  causes  leading  to  these  two 
distinct  types  of  paralysis  as  we  have  observed  them  in  the  prey  of 
solitary  wrasps.  Having  already  glanced  at  the  spider's  anatomy,  it 
will  be  well  for  the  sake  of  comparison,  to  look  into  the  anatomy 
of  the  roach.  In  the  first  place  the  two  belong  to  different  phyla; 
one  is  an  arachnid,  the  other  an  insect.  Therefore  they  will  differ 
physically. 

In  the  spider  we  find  the  ganglions  clustered  about  the  oesophagus, 
concentrated  into  one  particular  section  of  the  body  and  easily  ac- 
cessible. In  the  roach  they  are  spread,  more  or  less,  throughout  the 
insect.  There  is  a  brain,  three  pairs  of  ganglions  in  the  thorax, 
followed  by  six  pairs  in  the  abdomen,  a  problem  indeed  for  the  wasp 
who  would  paralyze  such  a  complicated  creature. 

I  have  not  been  fortunate  in  observing  either  the  roach-killer  or 
the  lumberess  in  the  act  of  stinging  their  prey,  but  here  is  what  I 
believe  to  be  the  case  in  view  of  the  facts :  To  reach  the  isolated  nerve 
centers  at  the  outset,  to  bring  instant  and  complete  paralysis  to  her 


52  INSECT  BEHAVIOR 

victim,  the  wasp  would  find  it  necessary  to  drive  her  sting  into  as 
many  different  places  as  there  are  ganglions.  Judging  from  the  con- 
dition of  the  prey  it  is  a  feat  quite  beyond  either  the  roach-killer  or 
the  lumberess.  Therefore  they  must  depend  upon  one  or  two  thrusts 
to  stun  the  insects.  As  the  sting  plunges  home  it  ejects  a  tiny  drop  of 
poison  which  gradually  spreads  throughout  the  victim's  body,  bring- 
ing on,  in  due  time,  the  gradual  paralysis  that  we  have  observed. 

Gradual  paralysis  would  appear  to  be  dangerous  to  young  wasps. 
They  are  very  tender  creatures.  A  cricket  or  roach  thrashing  about 
within  the  cell  would  soon  cause  fatal  bruises,  but  nature  has  looked 
out  for  them  nicely.  If  undisturbed,  the  roach  and  cricket  lie  quietly 
enough.  Upon  their  lower  surfaces  lie  the  wasp's  white  eggs,  but 
they  are  motionless.  In  forty-eight  hours  the  wasplets  emerge,  tiny 
creatures,  three  millimeters  in  length,  whose  baby  mouths  do  not 
disturb  the  sleepers.  In  another  day  they  begin  to  really  chew  their 
hosts,  but  by  this  time  paralysis  has  set  in. 

There  is  no  significance  in  the  two  types  of  paralysis.  They  are 
present  in  the  spider  and  the  roach,  simply  because  of  the  physio- 
logical difference  existing  between  the  two.  Thus  the  grubs  of  the 
roach-killer  and  the  lumberess  and  those  of  the  spider  hunters  live 
much  the  same.  One  is  as  safe  in  its  respective  cell  as  another,  so 
there  we  shall  leave  them. 


H 


CHAPTER  VI 

THE  FOREST  SHELL- WASP 

Zethusculus  hamatus  Zav 

OW  early  one  thing  begins  to  support  another  in  the  jun- 
gle! Even  the  infant,  thread-like  air  root,  new  born  from 
the  parent  liana,  sustains  a  spiral  of  fairy  moss  and  later 
a  tiny  emerald  wasp's  nest,  fashioned  from  the  ribbon 
of  the  sporophyte.  The  great  cool  jungle  reminds  me  of  a  jig-saw 
puzzle,  the  pieces  of  which  are  its  life,  entwined  and  ingrown,  each 
using  another  for  its  own  particular  success  and  to  complete  its  part 
in  the  great  green  picture.  A  giant  liana  supported  by  a  still  greater 
tree;  thread-like  offspring  supported  by  the  liana,  fairy  moss  living 
upon  the  thread-roots,  wound  in  its  turn  into  the  hoop-like  walls  of 
an  insect  nursery.  Here  at  least  are  five  fragments  of  the  great  puz- 
zle we  see  fitted  together. 

The  nursery  which  belongs  to  the  shell-wasp  of  the  forest  reminds 
me  of  two  algae-grown  snails,  one  clinging  to  the  slender  stalk,  the 
other  to  its  sister's  tapering  shell.  In  reality,  the  two  shells  are  the 
cells  of  the  nest  fashioned  from  the  ribbon-moss  which  grows  upon 
the  air-root.  It  is  very  delicate  material.  One  must  look  sharply 
in  order  to  see  that  it  is  a  thing  separate  from  the  mere  thread  that 
supports  it.  Peeling  off  the  ribbon,  the  wasp  winds  it  into  little 
hoops,  one  upon  the  other,  and  cements  it  together  with  her  own  per- 
sonal glue.  The  building  material,  when  dry,  is  tough  and  quite 
waterproof.  Some  twenty  hoops,  half  a  millimeter  in  width,  com- 
plete each  cell,  and  the  freshly  made  nest  gives  off  an  emerald  sheen. 

53 


54  INSECT  BEHAVIOR 

In  each  cell  a  stumpy,  slightly  bowed  egg  is  laid,  two  and  a  half 
millimeters  long  and  a  third  as  wide.  It  is  yellow  in  the  center, 
fading  to  a  transparent  white  at  either  end.  The  yellow  center  is  in 
reality  the  young  wasp,  and  the  transparent  end,  the  extremities  of  the 
film-like  egg  shell.  The  eggs  are  laid  one  at  a  time,  that  is  to  say, 
the  wasp  deposits  in  one  cell,  waits  for  it  to  hatch,  then  provides  the 
young  with  sufficient  food  to  bring  it  to  maturity  and  plugs  the  cell 
with  moss  before  laying  the  second  egg. 

Its  chosen  prey  is  doubtless  small  caterpillars,  for  I  found  three 
uneaten  heads  in  a  cell  containing  a  full-grown  larva.  The  egg  is 
attached  to  the  roof  of  the  cell  by  its  posterior  end  near  the  back,  and 
hangs  downward.  Thus  the  young  wasp  hatches  with  its  head  in 
mid-air. 

The  mother  wasp  guards  her  cells  closely  during  the  period  of 
incubation,  often  resting  within  the  cell  containing  the  new  laid  egg. 
She  crawls  to  the  entrance  on  the  roof  of  the  nest,  then  turning  round, 
backs  in,  clinging  to  the  underside  of  the  roof.  Her  head  peering 
out,  with  its  antennae  waving  here  and  there,  adds  to  the  illusion  of 
the  nest  being  the  shell  of  a  snail. 

The  two  nests  on  which  this  life  history  is  based  were  found  on 
May  14,  in  the  deep  forest.  One  of  them  I  lost,  but  let  us  go  back 
to  that  day  and  the  remaining  nest.  If  I  leave  it  upon  its  swaying 
air-root  for  further  observation,  I  will  probably  never  find  it  again. 
It  blends  perfectly  with  the  emerald  surroundings,  a  tiny  object  in  a 
part  of  the  forest  that  I  have  visited  but  once.  Therefore  I  will 
carry  it  home  to  the  laboratory  just  as  it  is,  and  put  myself  in  diffi- 
culties at  once. 

The  first  cell  contains  a  full-grown  larva  and  the  second  is  empty, 
save  for  a  single,  freshly  deposited  egg.  The  larva  is  quite  satisfac- 
tory. It  has  finished  its  meal  of  caterpillars  and  will  soon  pupate, 
giving  me  much  desirable  information  and  no  trouble.  But  what  of 


THE  FOREST  SHELL-WASP.  55 

the  egg?  If  true  to  the  rule,  whidi  is  usual  among  solitary  wasps, 
it  will  become  a  hungry  living  grub  in  forty-eight  hours,  how  then 
shall  I  feed  it?  I  have  not  given  the  parent  wasp  a  chance  to  store 
provisions  for  her  larva,  yet  I  am  responsible  for  the  orphan. 

The  young  of  solitary  wasps  are  fed  on  a  variety  of  material,  but 
spiders  and  caterpillars  seem  to  be  most  frequently  chosen  as  prov- 
ender. This  I  know  from  experience  gained  in  the  examination  of 
a  great  many  nests.  In  the  light  of  the  present  difficulty  it  may  prove 
a  valuable  bit  of  knowledge.  The  victims  are  stored  within  the  cells 
in  a  paralyzed  condition  from  which  they  never  awake.  If  they 
were  killed  outright,  they  would  soon  putrefy  in  the  cells,  contam- 
inate the  budding  wasps  and  turn  the  healthy  nursery  into  a  colony 
of  lepers.  Therefore  instinct,  the  great  teacher  of  insects,  guides  the 
wasp's  sting  only  into  the  victim's  nervous  centers.  The  creature 
so  treated,  passes  into  a  comatose  condition  and  lies  powerless  to 
move  or  struggle  while  the  young  wasp  sucks  at  its  viscera.  This, 
then,  is  my  grewsome  course:  I  must  catch,  artificially  paralyze  and 
present  living  food  to  the  shell-wasp's  grub  if  I  am  to  rear  the  orphan 
successfully. 

A  search  for  caterpillars  of  the  proper  description  is  entirely 
unsuccessful.  They  must  be  minute,  soft,  and  without  hair  upon  their 
bodies  or  the  youngster  will  die  of  indigestion.  Moreover  it  is  the 
off  season  for  them  and  unlike  the  wasp  I  cannot  find  them  by  the 
sense  of  smell.  Therefore  as  an  experiment  I  substitute  spiders  for 
the  proper  diet  of  span-wrorms.  Spiders  are  abundant  and  easily 
paralyzed. 

The  nervous  system  of  a  spider  is  concentrated  in  a  mass  of  gan- 
glions gathered  about  the  oesophagus.  It  lies  in  the  cephalothorax, 
or  in  that  section  of  the  creature  which  is  foremost,  there  being  but 
two  divisions. 

I  secure  my  first  victim  from  its  web  in  the  window  corner.     It 


$6  INSECT  BEHAVIOR 

is  a  long-legged  creature  with  a  good  plump  body,  soft  and  unpro- 
tected. With  a  little  chloroform,  I  anaesthetize  it,  just  long  enough 
to  keep  the  creature  quiet.  As  soon  as  it  is  still,  I  clip  its  legs  off 
quite  short,  then  with  a  very  slender  needle  I  stab  the  cephalothorax 
in  two  places,  once  from  above,  once  from  below.  My  object  is  to 
reach  the  ganglions  mentioned  above,  thereby,  injuring  them  with  my 
needle  and  producing  a  sort  of  paralysis  in  the  spider.  The  experi- 
ment works  well  enough.  The  victim  quivers  for  a  moment,  then 
lies  motionless.  With  my  crude  sting,  represented  by  the  needle,  I 
have  imitated  as  closely  as  possible  the  methods  employed  by  the 
parent  wasp  in  preparing  food  for  her  offspring: 

Now  I  place  the  spider  in  the  cell  just  under  the  suspended  un- 
hatched  egg  of  the  wasp  and  await  developments.  In  two  days  the 
young  wasp  emerges  from  the  shell,  and  hangs  head  down,  still 
attached  at  its  anal  segment  to  the  cell  wall.  For  several  hours  I 
keep  close  watch,  during  which  time  it  pays  no  attention  to  the  para- 
lyzed spider.  It  scorns  my  work  and  the  repast  I  have  prepared  and 
hangs  helplessly,  its  mouth  sucking  rhythmically  at  the  air.  Now  I 
move  the  spider  so  that  one  of  the  stab  wounds  in  its  body  comes  in 
contact  with  the  larva's  mouth.  It  responds  frantically,  like  a  crea- 
ture dying  of  thirst,  to  the  liquid  that  oozes  from  the  wound.  It 
fastens  itself  by  the  mouth  to  its  victim  and  there  it  clings  like  a 
suction  pad,  its  entire  body  rippling  as  it  drains  the  spider's  life. 

Much  to  my  surprise  the  experiment  is  crowned  with  success.  In 
a  few  hours  a  change  is  noticeable  in  the  larva — it  has  grown  and 
gained  in  strength.  At  length  it  pulls  away  from  the  walls  of  the 
cell  and  settles  among  the  spiders  I  have  provided.  It  is  an  experi- 
ment especially  prolific  in  answering  abstract  questions  and  suggest- 
ing others.  It  proves  that  all  larvae  are  not  entirely  dependent  on 
one  certain  article  of  diet.  Doubtless  a  given  species  is  invariably 
supplied  by  the  parent  with  the  same  kind  of  food,  yet  we  have  posi- 


•j>  _s 

y    *" 

4Ml          gj 

~    i 

El 

3     et 
a  W 


B.g 


«     o 
S     0 


THE  FOREST  SHELL-WASP  57 

tive  proof  that  such  a  condition  is  not  imperative.  The  larva  has 
no  more  abhorrence  for  the  spider  than  for  its  natural  diet  of  cater- 
pillars. If  the  mother  wasp  but  knew  the  truth  she  might  store  her 
nest  with  the  ever  abundant  spider  in  years  of  caterpillar  scarcity. 

Further,  the  experiment  points  out  that  in  the  wasp's  victim, 
paralysis  may  be  brought  about  by  the  thrust  of  the  dart  unaided  by 
its  poison.  It  is  the  stabbing  and  injuring  of  the  ganglions  that  pro- 
duces the  effect,  at  least  in  the  case  of  the  spider. 

Is  the  poison  of  the  wasp  a  potion  for  prolonging  life  in  the  stores, 
rather  than  an  agent  for  producing  paralysis?  Do  wasps  that  attach 
their  eggs  to  the  cell  walls,  leave  the  doors  open  until  the  young 
wasps  hatch,  for  any  particular  reason?  These  are  questions  that  the 
experiment  suggests.  But  let  us  go  back  to  the  insect's  life  history. 

At  birth  the  young  wasp  measures  two  and  one-half  millimeters. 
It  is  a  milky  \vhite  grub  of  thirteen  segments  counting  the  head, 
which  is  a  round  bead-like  affair.  As  it  feeds  and  increases  in  size 
the  distinction  of  the  head  decreases.  At  first  the  head  is  nearly  the 
same  diameter  as  the  body  itself,  but  the  latter  soon  takes  on  flesh 
and  grows  many  times  its  original  size,  so  much  more  rapidly  than 
the  head  that  it  soon  greatly  surpasses  it. 

I  continued  to  feed  my  orphan  for  five  days,  which  is  the  average 
length  of  time  spent  gorging  by  the  Guiana  grub.  During  this  time 
it  consumed  several  small  spiders  that  I  paralyzed  and  placed  before 
it,  reaching  in  the  end  a  length  of  seven  millimeters  and  turning  a 
pale  yellow  color,  much  like  clouded  or  partly  sugared  honey. 

Now  the  grub  lies  motionless  for  three  days,  when  a  pellet  of  un- 
digested bits  of  spider  is  deposited  in  the  cell.  No  cocoon  of  any 
kind  is  spun;  instead  it  lies  upon  the  bare  hooped  floor  of  the  nursery, 
apparently  quite  contented.  All  wasps  rid  themselves  of  what  waste 
has  accumulated  during  larval  life  in  this  manner,  a  short  time  prior 
to  pupation,  the  majority  placing  it  in  the  lower  pole  of  the  cocoon, 


58  INSECT  BEHAVIOR 

where  it  acts  as  a  solid  plug.  When  the  waste  matter  is  expelled  the 
grub  often  loses  its  original  color,  which  is  due  only  to  the  sewage 
showing  through  its  transparent  skin.  In  the  case  of  the  shell-wasp, 
it  changes  from  a  clouded  honey  color  to  white,  slightly  tinged  with 
yellow.  It  also  becomes  more  opaque. 

Ten  days  after  excretion  the  insect  pupates.  Then  comes  another 
wait  of  three  weeks  before  the  final  wasp  issues  from  its  cell. 

During  these  twenty-one  days,  the  pupa  receives  its  finishing 
touches — at  first,  when  the  transformation  from  the  larval  state  takes 
place,  there  is  no  dark  pigment  in  the  body.  It  is  yellowish  white 
and  rather  translucent.  Color  appears  first  in  the  eyes,  which  turn 
light  lavender,  then  brown  and  finally  black.  Next,  the  pigment  ap- 
pears in  the  remainder  of  the  head.  Then,  as  though  coming  through 
some  hidden  tunnel  below  the  flesh,  it  appears  as  a  mere  dot  of  dark 
fluid  in  the  center  of  the  thorax.  Slowly  the  dot  expands,  throwing 
out  arms  of  color  which  later  combine  and  fill  the  entire  thorax  with 
pigment,  like  a  rocket  that  unfolds  its  display  in  the  sky.  Next  the 
slender  petiole  of  the  abdomen  becomes  clouded.  This  soon  gives 
place  to  darker  color  while  its  recent  cloudiness  appears  in  the  abdo- 
men itself.  At  length  the  entire  insect  turns  black  save  for  the  three 
small  orange -yellow  patches  on  its  abdomen. 

This  general  dullness  is  due  to  the  pupal  skin  in  which  the  finished 
wasp  is  now  resting.  We  see  it  through  this  delicate  membranous 
covering  which  is  immeasurably  thin,  and  fits  the  insect  as  closely 
as  her  own  external  skeleton.  Under  the  transparent  covering  the 
insect  appears  dull,  but  otherwise  quite  normal  except  for  her  wings. 
Her  legs  and  antennae  are  of  proper  length,  her  head  and  body  neatly 
proportioned,  yet  her  wings  are  but  a  third  the  natural  size.  They 
are  hollow  appendages  intricately  folded  and  held  in  place  by  the 
wing  bags  of  the  membranous  covering.  Later  with  the  pupal  skin 
of  which  they  are  a  part,  these  bags  are  shed,  releasing  the  true  wings, 


THE  FOREST  SHELL-WASP  59 

which  unfold  to  their  full  extent  under  a  pressure  of  liquid  which 
flows  into  them  from  the  wasp's  body.  Later  the  liquid  is  withdrawn 
and  they  dry  as  thin,  brittle  appendages. 

When  the  pupal  membrane  is  cast  the  wasp  requires  at  least  another, 
day  to  rest  and  gain  strength  for  her  emergence.  She  does  not  issue 
into  the  world  in  the  wet,  weak  condition  of  the  butterfly,  to  rest  and 
dry  in  the  sunshine  before  flying  to  seek  her  mate.  Instead  she  makes 
her  toilet  within  the  cell  and  waits  for  full  strength  before  emerging. 
Then,  everything  ready,  with  knife-like  mandibles,  she  cuts  a  neat 
round  hole  through  the  mossy  wall  and  casts  herself  to  the  lot  of 
fate.  - 

We  see  her  as  she  emerges,  all  glistening  with  the  youth  of  a  new 
generation.  A  scant  forty  days  have  passed  since  the  mother  wasp 
fashioned  the  emerald  nursery  upon  the  swinging  air  root. 


1 


CHAPTER  VII 

THE  ONE-BANDED  DAUBER 

Sceliphron  fistulare    (Dahlb) 

physiological  phases  of  the  dauber's  life  history  natu- 
rally adhere  to  a  set  of  invariable  rules — the  egg  hatches  in 
a  certain  length  of  time,  the  larva  feeds  until  the  spiders  in 
its  cell  are  consumed  and  in  the  course  of  certain  definite 
periods  the  insect  pupates  and  emerges.  Her  nest  is  of  clay,  her  pro- 
visions spiders,  but  otherwise,  in  the  remainder  of  her  nesting  activi- 
ties, this  wasp  is  a  creature  that  follows  no  rule.  Her  nursery  may 
be  but  a  single  earthen  cell  or  it  may  boast  a  group  of  twelve.  It 
may  be  fastened  to  a  twig,  to  the  side  of  a  house,  to  a  sheltering  stone 
or  on  the  edge  of  a  narrow  shutter  slat — one  nest  is  a  long  flat  object 
humped  at  one  end  with  additional  cells  and  decorated  with  strips 
of  variegated  clay,  another  is  top-shaped;  still  another  is  but  a  single 
gray  cell,  half  circular  at  one  end  and  quite  round  at  the  other.  They 
vary  endlessly  according  to  the  energy  and  taste  of  the  individual 
builder,  therefore  I  cannot  describe  any  one  nest  as  the  usual  type — I 
may  tell  only  of  the  building  of  a  cell.  It  may  be  the  first  room 
framed  in  an  elaborate  plan,  or  the  completed  nest  of  the  dauber, 
but  my  remarks  will  apply  to  any  nest. 

Upon  a  brick  pillar  supporting  the  laboratory  the  wasp  laid  the 
corner-stone  of  her  nest.  Twelve  loads  of  brown  mud,  tamped  out 
into  flat  pies,  side  by  side,  sufficed  for  the  foundation.  The  material 
was  carried  in  little  round  pellets  weighing  one-tenth  of  a  gram. 
They  were  borne  in  the  wasp's  mandibles  from  a  moist  spot  in  a  flat 


THE  ONE-BANDED  DAUBER  61 

clearing  nearby.  Each  pellet  was  tamped  and  arranged  with  great 
care,  during  which  time  the  wasp  buzzed  continually  and  held  her 
abdomen  at  the  end  of  its  long  petiole  high  in  the  air,  as  a  balance 
weight  to  the  lowered  head  on  the  other  end.  The  forelegs  were  used 
as  much  as  the  mandibles,  thus  her  dumbbell-like  body  swung  pivoted 
upon  the  central  pair  of  legs. 

When  the  foundations  were  laid  she  proceeded  with  the  cell  itself, 
bringing  thirty  loads  of  mud  per  hour.  In  a  little  over  two  hours 
the  cell  was  complete,  a  neatly  rounded  tube,  thirty  millimeters  long 
and  sixteen  millimeters  in  diameter,  the  result  of  some  sixty-five  loads 
of  mortar. 

In  fashioning  the  tube,  the  first  few  pellets  were  deposited  side  by 
side  and  raised  into  a  semi-circular  mound,  or  half  disk  stood  on  end. 
Here  again  the  work  was  accomplished  with  her  mandibles  and 
forelegs.  The  clay  was  pinched  up  between  the  tarsi  and  then  shaped 
principally  with  the  mandibles,  which  acted  like  a  pair  of  flattened 
tongs.  When  the  disk  was  finished  the  successive  loads  of  mud  were 
pressed  against  its  inner  surface,  usually  at  one  side  and  then  moulded 
into  a  narrow  ridge  running  around  its  circumference.  Thereafter 
each  pellet  was  fashioned  into  a  ribbon  of  plaster  placed  against  the 
side  of  the  preceding  layer.  When  the  job  was  finished  these  indi- 
vidual layers  were  quite  visible  so  that  the  separate  rings  of  which  the 
nest  was  constructed  could  easily  be  counted. 

In  coming  to  her  nest  the  wasp  often  experienced  great  difficulty 
in  locating  it.  She  would  approach  the  brick  pillar  with  her  mortar 
pellet,  circle  the  column  once  and  then  alight,  as  a  general  rule,  some 
distance  above  or  below  the  nest.  A  thorough  inspection  of  the  spot 
to  which  her  general  sense  of  direction  brought  her,  would  follow. 
This  inspection  never  extended  beyond  one  or  two  bricks  at  most. 
Finding  the  cell  missing,  she  would  take  wing,  circle  the  pillar  once 
more  and  alight  in  a  new  location.  Sometimes  this  performance  was 


62  INSECT  BEHAVIOR 

repeated  over  and  over,  until  at  length  she  would  come  by  chance 
upon  the  brick  supporting  the  object  of  her  search. 

Different  species  of  wasps  vary  greatly  in  degrees  of  accuracy  in 
rinding  their  nests.  Some  experience  no  difficulty  whatever,  others 
have  slight  trouble,  while  still  others  spend  at  least  one-third  of  their 
nesting  period  searching  for  the  elusive  keyhole.  So  true  is  this 
among  solitary  wasps  that  they  might  be  divided  into  several  groups 
in  the  order  of  their  respective  accuracy.  One  group  would  contain 
the  wasps  which  build  their  nests  in  the  ends  of  hollow  reeds.  The 
home  doorway  may  be  in  the  midst  of  a  dozen  others,  yet  the  owner 
flies  directly  to  her  own  threshold  without  an  instant's  hesitation. 
The  long  black  reed  wasp  l  and  the  white-footed  wasp  2  would  be 
shining  examples  of  this  enlightened  group.  Again  we  have  such 
wasps  as  the  red-legged  digger  3  who  locates  her  tunnel  in  the  ground 
only  after  a  series  of  circular  flights  in  the  air  above  it,  much  as  a 
carrier  pigeon  does  upon  release,  before  turning  in  the  homeward 
direction.  In  the  third  group,  the  one-banded  dauber  might  head 
the  list  of  blunderers  who  find  their  cells  only  after  a  search,  some- 
times of  great  length,  with  the  loss  of  much  valuable  time  and  energy. 

I  do  not  believe  that  sight  is  an  important  factor  to  be  considered 
in  any  of  the  above  cases.  Most  insects  do  not  see  such  small  objects 
as  their  nests  clearly  from  a  distance.  It  is,  to  some  extent,  a  sense 
of  smell,  after  the  main  journey  has  been  accomplished,  but  they 
rely  chiefly  on  a  sense  of  direction.  Some  have  it  more  highly  de- 
veloped than  others,  just  as  the  Indian  finds  his  way  in  the  forest  un- 
aided by  compass,  where  another  individual,  a  white  man,  would 
fail  or  perhaps  blunder  through  to  his  camp.  The  one-banded  dauber 

flies  accurately  enough  to  her  brick  pillar,  but  lacks  that  balanced 

/ 

1  An  unidentified  species  of  Trypoxylon. 

2  Trypoxylon  leucotrichium  (Chap.  IV). 
8  A  species  of  Sphex. 


THE  OXE-BAXDED  DAUBER  63 

sense  of  direction  that  lands  the  white-footed  wasp  in  a  single  flight 
at  her  doorway. 

In  the  wooden  shutters  of  the  laboratory,  I  found  further  evidence 
of  the  dauber's  stupidity.  For  a  nesting  site,  she  had  selected  in 
this  case  the  narrow  edge  of  a  slat,  situated  midway  between  the  top 
and  bottom  of  the  shutter.  Below  her  site  were  a  dozen  other  slats, 
each  affording  a  building  plot  similar  in  every  way  to  the  one  she 
had  selected.  Above  her  were  as  many  more.  This  made  her  work 
difficult;  as  it  finally  proved,  too  difficult  for  her  limited  sense  of 
direction.  She  laid  the  foundation  of  her  nest  in  a  maze  of  sites, 
each  exactly  like  those  above  and  below,  and  in  the  end  her  design 
perished.  Her  pellets  of  mud  were  deposited  upon  four  different 
slats,  one  below  the  other,  until  four  different  cells,  three  inches  apart, 
commenced  to  take  form.  Arriving  laden  with  her  ball  of  mud  she 
would  fly  to  the  general  location  of  her  original  foundation,  but  to 
distinguish  which  slat  among  so  many  similar  ones  supported  her 
original  masonry  was  quite  beyond  her.  Thus  she  worked,  vainly 
endeavoring  to  finish  her  nursery  in  the  usual  space  of  time,  laboring 
the  while  on  four  widely  separated  cells!  Eventually  she  abandoned 
the  job  in  despair,  and  indeed  it  must  have  been  discouraging.  To 
return,  hour  after  hour,  laboriously  carrying  that  heavy  mortar  to 
a  house  that  refused  to  grow,  might  easily  discourage  a  stouter  heart 
than  the  dauber's. 

That  she  concentrated  her  efforts  entirely  upon  four  slats  was  an 
interesting  fact.  It  gives  us  some  idea  to  what  degree  of  perfection 
her  senses  of  smell  and  direction  are  developed.  The  first  slat  bear- 
ing evidences  of  her  workmanship  was  situated  twelve  inches  above 
the  fourth  and  lowest  one.  Xow  as  the  wasp  always  returned,  with 
her  pellets,  to  one  of  these  four,  it  is  logical  to  suppose  that  her 
sense  of  direction  was  developed  accurately  enough  to  bring  her 
within  twelve  inches  of  the  actual  location  of  her  nest.  Observation 


64  INSECT  BEHAVIOR 

of  the  insect  whose  nest  I  found  upon  the  brick  pillar  strengthened 
this  evidence.  This  wasp  never  returned  directly  to  her  nest  at  the 
outset,  but  at  the  same  time  never  alighted  with  her  burden  more 
than  a  full  twelve  inches  from  it.  From  such  a  position  she  would' 
walk  about  in  a  zigzag  course,  until  at  length  the  brick  bearing 
the  nest  was  reached.  Once  this  "home  brick"  was  located,  the  insect 
would  walk  straight  to  her  nest.  The  dauber  returns  to  the  general 
locality  without  much  difficulty,  but  actually  to  reach  the  cells  she 
must  feel  about  with  curled  antennae,  and  depend  upon  smell  rather 
than  a  mere  sense  of  direction. 

To  build  a  cell,  including  its  foundation,  requires  between  seventy 
and  eighty  loads  of  mortar.  The  freshly  made  nursery  weighs  about 
seven  and  two-thirds  grams,  but  by  the  time  it  is  ready  to  receive 
provisions,  evaporation  has  reduced  it  to  three.  From  these  figures 
I  conclude  that  to  build  a  nest  containing  ten  cells  requires  some 
seven  hundred  pellets  of  mud.  In  accomplishing  her  task  the  tireless, 
energetic  mason  carries  1,000  times  her  own  weight  in  mortar  and 
fashions  it  grain  by  grain  into  the  abode  for  her  progeny. 

In  storing  her  cells,  the  dauber  shows  a  varied  taste.  I  have  before 
me  two  open  cells.  One  contains  two  large  fat  spiders  that  easily 
fill  the  storeroom,  the  other  is  stored  with  a  variety  of  victims,  nine 
in  all,  including  many  grades  of  size  and  color.  In  these  two  cells  I 
have  at  least  two  genera  and  five  different  species  of  paralyzed 
spiders. 

Upon  the  side  of  the  abdomen  of  the  largest  one  in  each  cell,  the 
wasp  deposits  a  pale  yellowish  white  egg,  then  she  seals  the  nursery 
entrance  with  a  few  pellets  of  mortar  and  abandons  the  nest  for  good. 

In  seventy-two  hours  the  egg  hatches,  or  I  should  say,  comes  to 
life.  Here  is  a  strange  process.  Watching  the  erstwhile  egg  through 
the  lens,  a  spasm  suddenly  takes  place  within  its  film-like  shell,  which 
is  nearly  transparent  and  allows  a  fairly  clear  view  of  what  takes 


One-banded  dauber  freshly  emerged  from  her  cocoon. 
Enlarged  twice 


Suspended  hatching  egg  of  the  forest  shell-wasp.    En- 
larged seven  times 


\ 


One-banded  dauber  working  upon  her  nest.     One- 
third  natural  size 


Four  types  of  nests  made  by  the  one-banded  dauber. 
One-third  natural  size 


THE  OXE-BANDED  DAUBER  65 

place  within.  This  spasm  is  a  sort  of  pumping  wave,  similar  to  the 
movement  in  a  big  fire  hose  under  pressure  from  the  engine.  It 
starts  at  the  anterior  end  of  the  egg  and  traverses  its  entire  length, 
fading  out  as  it  reaches  the  opposite  end  from  which  it  started.  Thus 
does  the  new-born  take  its  first  mouthful  of  liquid  food  from  the 
spider.  There  is  no  actual  hatching  and  crawling  forth  from  the 
egg,  no  empty  shell  behind  the  larva.  Instead,  its  mouth  appears 
first  to  eat  a  tiny  opening  through  the  film  that  encloses  it,  after 
which  the  grub  finds  its  mouth  flat  upon  the  spider's  abdomen.  As 
the  pumping  spasms  continue,  each  one  representing  a  swallowed 
mouthful  of  spider  substance,  the  nursling  increases  very  gradually 
in  bulk.  In  a  few  hours  after  taking  its  first  draught  of  foodstuff, 
the  egg-film  apparently  splits  along  the  center  of  the  larva's  back, 
one  end  of  the  breach  traveling  in  either  direction,  exposing  the 
actual  skin  of  the  young  wasp.  The  breach  spreads  like  a  drop  of  oil 
upon  water,  only  much  more  slowly,  but  twenty-four  hours  after 
the  first  spasm  not  a  vestige  of  film  remains.  It  appears  to  have  been 
absorbed  into  the  larva's  body.  Under  the  lens  it  vanishes  slowly 
before  my  eyes,  yet  I  cannot  see  where  it  goes,  and  when  the  process 
is  over  I  can  find  no  trace  of  it,  either  on  the  larva  or  its  spider  host. 
The  grub  is  a  living  dialyzer  through  wrhose  delicate  skin  the  egg- 
film  appears  to  osmose.  In  other  words,  I  believe  that  the  film  is 
absorbed  into  the  insect's  body  in  minute  particles  in  much  the  same 
manner  that  food  passes  through  the  walls  of  the  oesophagus  to  reach 
the  distributing  corpuscles. 

It  is  possible  that  the  larva  eats  the  egg-film,  but  if  so  it  is  drawn 
into  the  mouth  so  gradually  and  with  such  skill  that  it  is  impossible 
to  detect  the  operation.  Therefore,  I  suggest  that  the  process  may 
be  akin  to  osmosis.  The  action  is  so  gradual,  so  smooth  and  unin- 
terrupted that  I  can  think  of  no  other  way  to  describe  it. 

At  first  the  young  wasp  lives  only  on  liquid  foods.     During  the 


66  INSECT  BEHAVIOR 

first  few  hours  of  its  life  its  mandibles  are  of  a  very  rudimentary 
character,  in  fact  scarcely  distinguishable  until  the  grub  is  a  day  or 
more  old — and  are  developed  gradually  to  be  in  readiness  later  when 
substantial  parts  of  the  spider  must  be  eaten.  The  fact  that  at  birth 
the  grub  possesses  no  adequate  appendages  for  chewing  suggests  an 
interesting  question:  How  does  the  tender  creature  make  the  first 
incision  through  the  mature  wall  of  the  spider's  abdomen?  Perhaps 
the  parent  wasp  pricks  it  and  uses  the  minute  drop  of  fluid  that  oozes 
from  the  wound  as  mucilage  with  which  to  secure  the  position  of  her 

egg- 

The  grub  feeds  for  six  days — during  this  time  it  goes  about  its 
meal  in  a  thorough  manner  so  that  in  the  end  not  a  hair  of  the  stored 
spider  remains.  Further  the  larva  has  changed  greatly  in  size.  At 
birth  it  measures  four  millimeters,  now  it  is  seventeen  millimeters 
long  and  ready  to  spin  its  cocoon. 

Spinning  is  a  laborious  process  requiring  three  whole  days.  A 
slight  network  of  silk  is  first  thrown  about  the  cell,  within  which 
an  inner  cocoon  of  a  far  more  substantial  character  is  then  con- 
structed. It  is  somewhat  longer  than  the  grub,  torpedo-shaped  and 
reddish  brown  in  color,  which  is  due  to  the  varnish,  so  commonly 
employed  by  the  larvae  of  Hymenoptera,  showing  through  from  the 
inside. 

The  cocoon  is  in  no  way  remarkable,  in  fact  it  is  quite  simple.  I 
have  seen  other  larvae  build  more  elaborate  ones  in  a  day,  yet  the 
dauber  requires  seventy  odd  hours  for  so  simple  an  operation.  Its 
nature  is  sluggish  from  the  outset,  and  throughout  its  immature  life 
it  is  slow  about  its  affairs.  The  egg  requires  three  days  to  hatch,  the 
grub  feeds  six  days,  therefore  it  logically  follows  that  spinning  should 
be  a  leisurely  process.  Consequently,  the  grub  takes  its  time  and 
is  none  the  worse  for  it. 

Seven  days  after  spinning,  pupation  takes  place.    The  creature  now 


THE  OXE-BAXDED  DAUBER  67 

lies  motionless  in  the  usual  quiet  state  that  accompanies  this  condition. 
Colorless  and  stately,  lying  upon  its  back  with  folded  arms  in  its 
tomb  of  masonry,  the  pupal  corpse  awaits  a  reincarnation  that  in 
twenty  days  brings  forth  a  perfect  insect. 

Stupid  affairs  of  the  wasp  world  are  generously  heaped  upon  the 
dauber.  Before  me  lies  an  oddly-shaped  nest  of  her  making  wrhich 
I  have  opened  for  inspection.  It  contains  twelve  cells  and  as  many 
cocoons,  ten  of  which  have  been  burst  open  by  the  young  wasps  who, 
alas,  lie  dead  and  shriveled  in  their  cells.  Their  heads  face  the 
mortar-plugged  doors  of  the  prison,  which  bear  marks  of  frantic 
efforts  to  escape,  yet  each  has  died  of  starvation,  unable  to  reach  the 
outer  world. 

Herein  lies  the  reward  of  stupidity.  The  dauber,  whose  life  seems 
made  up  of  errors,  chose  for  her  nest  the  first  mortar  that  she  chanced 
to  find.  It  was  not  soft  gray  mud  from  a  puddle,  or  the  sandy  orange 
surface  of  the  clearing,  but  a  pasty  yellow  clay.  It  kneaded  ad- 
mirably when  soft  and  fresh  but  in  hardening  turned  to  rock.  The 
offspring  grew  normally  within,  spun  their  cocoons  and  passed  suc- 
cessfully to  finished  insects,  but  were  unable  to  emerge.  They  ham- 
mered and  gnawed  and  scraped  at  the  mortar;  the  nest  bore  evidence 
of  the  effort  put  forth,  but  all  in  vain.  The  mortar  resisted  and  the 
young  wasps  died.  Thus  on  the  very  eve  of  their  emergence  the 
dauber's  offspring  were  obliterated  by  her  stupidity.  I  wonder, 
even  if  there  were  a  tiny  glimmer  of  intelligence  in  her  little  dome, 
whether  she  would  see  the  error  of  her  ways? 


CHAPTER  VIII 

THE  BLUE  HUNTRESS 

Chlorion  neotropicus,  Kohl 

CLOSE  to  the  out-house,  whose   rough  frame  supports  the 
nursery  of  the  blue  huntress,  lies  a  heap  of  rich  red-orange 
clay,  thrown  up  from  a  pit  on  the  trail  to  the  forest.    It  at- 
tracts a  dozen  busy  mason-wasps  who  arrive  from  far  and 
near  to  gather  up  the  pliable,  ready-made  mortar  and  bear  it  away 
to  their  nests.    We  are  concerned  only  with  a  single  member  of  the 
laboring  crowd.    She  is  at  once  distinct  in  size.    Her  rich  metallic 
color  attracts  our  attention  and  holds  it  over  eleven  less  comely  ones. 
The  cement  which  she  is  gathering  is  pliable  like  putty,  but  filled 
with  tiny  bits  of  stones  that  make  its  contents  similar  to  that  of  very 
fine  concrete.    These  tiny  stones,  which  are  large  rocks  to  the  insect, 
lend  themselves  admirably  to  the  needs  of  her  nest.     They  lend  a 
rough,  rugged  appearance  to  the  three-celled  nursery,  but  form  an 
impregnable  barrier  against  a  host  of  enemies. 

The  building  material  is  laid  on  in  irregular  heaps.  They  dry 
very  rapidly  as  the  work  progresses,  giving  the  nest  the  appearance  of 
a  bit  of  fairy  hill  country  covered  with  a  thousand  disorderly  loads, 
spilled  helter-skelter  from  as  many  tiny  dump  carts.  The  wasp  cares 
little  for  outside  appearances,  which  are  of  no  account.  She  is  con- 
cerned chiefly  with  finishing  the  interior,  which  is  a  far  more  serious 
matter. 

Within,  the  cells  are  quite  as  smooth  as  they  are  rough  without,  a 
condition  necessary  in  view  of  the  delicate  contents  they  are  to 

68 


Spider  prey  of  the  blue  huntress,  showing  egg  of  the  wasp  attached  to  its  abdomen.     Greatly  enlarged 


Pupa  of  the  blue  huntress,  showing  T-shaped  jacks,  which  support  the  creature's  abdomen,  thus  protecting  it 

legs.     Greatly  enlarged 


THE   BLUE   HUNTRESS  69 

shelter.  The  slightest  projecting  bit  of  stone  work,  even  a  sharp 
grain  of  sand  overlooked,  might  injure  the  tender  bodies  of  the  in- 
sect's" offspring.  Thus  we  see  her  tamping  a  tiny  pebble  or  a  bit  of 
hardened  mortar,  until  it  sinks  into  the  smooth  wall  of  the  chamber. 
Over  and  over,  she  inspects  her  work,  scraping,  brushing,  tamping, 
until  the  cradle  bears  no  resemblance,  except  that  of  color,  to  the 
coarse,  sticky  substance  from  the  pit.  Her  nest  reminds  me  of  a 
callow  suburban  home,  terra  cotta  and  jagged  stones.  Her  taste  is 
not  cultured,  but  we  may  excuse  her  quite  readily.  She  specifies  these 
droll  materials  for  a  vital  reason. 

The  huntress  is  a  skilled  worker — she  is  a  prodigy,  requiring  but 
a  single  tool  to  fashion  the  mortar  nursery.  The  tip  of  her  abdomen 
is  a  veritable  tool  chest  all  in  one,  a  universal  appliance  with  which 
the  work  is  done.  True,  she  gathers  and  carries  material  writh  her 
mandibles,  but  the  house  itself  is  wrought  by  the  last  segment  of  her 
body.  It  is  a  modeler's  gouge,  with  which  she  measures  the  cells, 
decides  their  contour,  smooths  their  walls  and  fashions  the  entrances. 
Throughout  the  building  one  finds  tiny,  triangular  indentures,  where 
the  tool  has  left  its  impression. 

The  finished  nest  consists  of  three  tubes,  placed  one  upon  another. 
They  are  open  at  one  end,  where  the  entrances  are  slightly  funnel- 
shaped  like  the  mouths  of  flower  vases.  The  tubes  or  cells  measure 
thirty-four  millimeters  in  diameter.  There  is  variation  to  a  slight 
degree,  but  the  measurements  are  the  average  of  several  nests.  The 
insect  works  energetically,  completing  the  work  in  five  days.  One 
cell  is  constructed,  provisioned  and  an  egg  deposited,  before  a  second 
one  is  commenced. 

As  soon  as  a  cell  is  finished,  the  wasp  sets  out  in  search  of  pro- 
visions with  which  to  assure  the  successful  life  of  her  offspring.  She 
travels  the  open  sunny  trails,  or  the  dark  floor  of  the  forest.  One  is  as 
good  as  another,  provided  there  are  dead  leaves  or  fallen  branches 


70  INSECT   BEHAVIOR 

that  shelter  her  prey  from  less  agile  creatures  than  herself.  We  see 
her  alight  upon  the  ground  and  search  diligently  under  every  leaf 
and  branch  that  chances  in  her  path.  Her  antennae  are  curled  over, 
so  that  the  end  of  each  forms  a  perfect  loop.  She  thrusts  them  ahead 
of  her  and  depends  upon  their  sensitive  pores  to  locate  the  big  tawny 
spiders  that  constitute  her  prey.  She  is  always  nervously  alert,  her 
body  tense  and  ready  at  an  instant's  notice  to  spring  back  out  of 
danger.  As  she  works,  her  big,  steel  blue  wings  quiver  continually 
as  though  with  excitement  over  the  possibilities  of  each  new  leaf  and 
shelter  that  she  explores. 

Her  course  is  irregular.  Here  she  searches  for  perhaps  a  minute, 
followed  by  a  longer  investigation  some  fifty  feet  away.  Now  the 
hunt  leads  her  back  to  the  starting  point  and  later  to  the  intervening 
ground,  which  is  searched  minutely.  At  other  times  she  walks  in  a 
zigzag  fashion  for  a  great  distance,  even  though  unsuccessful  in  the 
end.  It  is  a  surprise  to  me  that  she  finds  her  elusive  and  protectively 
colored  prey  at  all.  You  wonder  why?  Then  search  among  the 
leaves  for  the  spider  that  serves  to  provision  her  nest.  You  will 
scarcely  find  one,  even  in  a  whole  day's  hunt,  yet  the  huntress  is  a 
dominant  insect,  seldom  defeated  in  her  quest. 

At  length  the  spider  is  found  lurking  beneath  a  brittle  leaf.  Her 
antennae  telegraph  the  information  to  a  tiny  brain  and  instantly  the 
wasp  springs  back  as  though  surprised.  A  second  later  she  recovers 
and  thrusts  herself  into  the  spider's  den.  Her  body  bends  under 
her  so  that  the  deadly  sting  protrudes  almost  beyond  the  head.  At 
the  first  movement  from  the  spider,  she  springs  back  again  with 
quivering  wings.  The  manoeuvre  is  repeated  over  and  over  until 
her  prey  is  at  length  forced  unconsciously  into  a  convenient  position. 
Then,  like  a  flash,  she  is  upon  the  unfortunate.  Her  sting  plunges 
deeply  into  the  creature's  nerve  center  and  instant  paralysis  results. 

The  spider  is  not  killed  outright.    In  that  case  it  would  decompose 


THE   BLUE   HUNTRESS  71 

and  become  dangerous  fare  for  the  young  wasps.  Instead,  it  is 
simply  paralyzed.  It  will  never  move  again  to  protest,  or  protect 
itself.  Perhaps  it  may  react  automatically  with  a  slight  quivering  of 
the  legs  when  touched,  but  henceforth  it  will  yield  to  whatever  fate 
has  in  store  for  it.  The  victim  will  awake  from  unconsciousness  only 
as  a  part  of  another  living  creature,  when  spider  substance  has  been 
eaten  to  build  the  body  of  a  wasp. 

The  spider  is  a  larger  creature  than  the  wasp  herself,  yet  she 
manages  to  fly  laboriously  to  her  nest,  carrying  her  victim  by  one 
of  its  palpi,  clasped  between  her  mandibles.  To  gain  access  to  her 
nest,  she  must  enter  the  outhouse  through  a  slatted  window,  the  lowest 
part  of  which  is  three  feet  from  the  ground.  Once  she  missed  the 
opening  and  tumbled  with  the  spider  headlong  to  earth.  She  was 
undismayed  by  the  fall,  never  once  relinquishing  her  hold,  but  I 
was  struck  by  the  difficulty  she  experienced  in  starting  once  more 
for  the  opening.  It  required  the  combined  strength  of  legs  and  wings 
to  drag  the  creature  up  the  perpendicular  wall  of  the  building  to  the 
slats  of  the  window. 

Once  within,  the  spider  is  dragged  to  the  waiting  cell,  where  it  is 
left  with  head  facing  the  entrance.  A  yellowish  white  egg,  projectile 
shape,  is  now  deposited  upon  the  side  of  its  abdomen.  This  accom- 
plished, the  wasp  returns  to  the  outside  of  the  nest.  Now  comes  a 
thorough  personal  clean-up  before  continuing.  The  forelegs  are 
drawn  through  her  mouth  and  rubbed  briskly  over  her  head  and 
antennas.  The  hind  legs  are  used  in  cleaning  the  wings  and  abdomen 
and  during  the  process  the  wasp  stands  almost  upon  her  head.  In  a 
few  minutes  she  is  clean  and  bright.  Doubtless  the  scrubbing  re- 
freshes her,  as  a  bath  puts  new  vigor  into  a  tired  man  who  has  worked 
faithfully  for  his  family  and  returned  home  with  the  sweat  of  labor 
still  upon  him. 

But  her  work  is  not  over  with  the  storing  of  the  spider.    She  has  yet 


72  INSECT   BEHAVIOR 

to  close  the  cell  with  a  seal  that  cannot  be  easily  broken.  The  job 
must  be  done  with  care,  and  quickly.  A  flaw,  ever  so  tiny,  in  the 
masonry,  may  jeopardize  the  helpless  inmates.  Wasplets  are  tender 
morsels,  fine  fare  for  many  a  parasite.  The  huntress  must  guard  the 
results  of  her  labor.  I  watched  this  interesting  process,  which  re- 
quired an  hour  from  the  time  the  spider  was  dragged  into  the  cell. 
It  was  only  a  tiny  doorway,  ten  millimeters  in  diameter,  yet  during 
those  sixty  minutes,  thirty  loads  of  clay  were  brought  to  the  nest  and 
packed  with  minute  care  into  the  entrance.  The  tiny  trowel  and 
scraper,  the  tamper  and  smoother,  all  combined  in  the  tip  of  her 
energetic  little  body,  must  have  been  worn  indeed  when  the  task  was 
finished.  But  there  was  no  sign  of  fatigue.  In  fact,  I  believe  she 
rejoiced  at  the  close  of  a  day,  well  spent  in  the  interests  of  her  race, 
without  a  thought  for  her  own  spent  body,  for  such  is  the  great  spirit, 
altruistic  even  though  unconscious,  that  rules  the  insect  world. 

The  last  cell  provisioned  and  sealed,  the  wasp  abandons  her  nest. 
She  deserves  a  rest  and  a  feast  of  nectar.  Henceforth,  nature  will 
take  charge  of  her  offspring  that  she  may  spend  her  declining  days 
unburdened. 

Within  the  cell,  the  egg  hatches  in  forty-eight  hours.  In  place  of 
the  tiny  albumen  filled  projectile,  we  have  a  soft  white  grub.  It  is 
footless  and  quite  unfitted  for  anything  but  the  consumption  of  food. 
It  possesses  no  sting  like  the  parent  huntress,  and  could  not  compete 
in  battle  with  the  most  primitive  insect,  yet  it  feeds,  immune  from 
danger,  upon  the  spider  that  lies  limply  within  the  cell.  Like  a 
foundling,  the  wasp  in  its  infant  state  is  reared  by  a  foster  parent. 
Like  the  child,  it  lives  only  upon  liquids,  drawing  them  from  the 
huge  bosom  of  its  spider  wet-nurse.  As  the  draining  goes  on  the 
spider's  body  shrivels  accordingly.  In  forty-eight  hours  the  pap  is 
exhausted,  but  now  the  grub  is  strong  enough  to  partake  of  solid  food. 


~     ~ 
~    o 


J-i 

" 


c.  o. 
e    S 


THE   BLUE   HUNTRESS  73 

Its  mandibles  are  capable  of  masticating  what  remains  of  the  feast. 
In. short,  it  sips  the  cream  first  and  eats  the  porridge  afterwards. 

After  five  days  of  continuous  gorging,  the  larva  treats  itself  to  a 
short  rest  before  spinning  its  cocoon.  During  the  five  days,  the  spider 
has-  vanished  so  completely  from  the  cell  that  only  a  microscope  re- 
veals a  few  uneaten  hairs.  These  adhere  to  the  larva's  tacky  skin, 
and  thus  escape  the  stomachward  journey.  I  have  never  seen  such 
a  hog!  Long  after  the  feast  is  over,  when  the  dishes  have  been  licked 
clean,  so  to  speak,  the  glutted  one  continues  to  Fletcherize  upon 
the  air. 

The  act  reveals  how  hard  and  fast  are  the  instinctive  rules  govern- 
ing the  insect's  behavior.  The  larva  hatches  upon  the  spider's  body. 
As  soon  as  its  mandibles  become  strong  enough,  they  commence  to 
tear  and  chew  automatically.  A  bit  more  or  a  bit  less  provender  in 
the  cell  is  of  no  consequence  whatever.  Once  started,  the  jaws  con- 
tinue to  work  for  a  certain  set  length  of  time  that  allows  for  variation 
in  the  bulk  of  the  stores.  Thus,  if  the  spider  be  a  bit  large,  it  will 
be  consumed  readily  enough.  If  a  bit  small  the  larva  will  simply 
continue,  as  I  have  said,  to  Fletcherize  upon  the  air  until  the  time 
limit  set  upon  the  active  period  of  its  mandibles  is  up.  The  insect 
is  an  automaton,  a  slave  to  a  power  that  is  not  intelligence. 

As  an  experiment,  I  introduce  two  spiders  into  a  cell  where  one  is 
the  normal  provender.  The  larva  consumes  nearly  all  of  the  feast, 
grows  to  an  abnormal  size,  but  eventually  dies.  This  would  appear 
to  contradict  the  existence  of  an  invariable  set  of  rules  governing  the 
insect's  life,  but  such  is  not  the  case.  I  have  interfered  in  the  normal 
course  of  events  and  artificially  changed  those  rules  at  the  outset  by 
doubling  the  amount  of  provisions  in  the  cell.  The  wasp's  life  is  like 
a  chemical  compound,  the  ingredients  of  which  correspond  to  these 
rules  and  depend  upon  one  another  for  the  ultimate  result.  Thus 


74  INSECT  BEHAVIOR 

if  we  alter  the  quantity  of  one  ingredient  the  desired  result  is  not 
obtained. 

The  experiment  has  in  no  way  disproved  that  the  creature's  life 
progresses  by  hard  and  fast  rules.  On  the  other  hand,  it  confirms  the 
statement,  and  further,  points  out  that  each  rule  depends  upon  the 
invariability  of  another  for  the  ultimate  success  of  the  wasp.  It 
also  tells  us  that  feeding  is  governed  by  the  amount  of  provisions  in 
the  cell.  Each  mouthful  stimulates  a  certain  number  of  strokes  from 
the  mandibles.  Thus,  when  the  normal  provender  is  consumed  by 
the  larva,  it  still  continues  to  chew  until  the  stimulus  is  gone.  In  the 
cell  containing  two  spiders,  the  poor  wasplet  found  no  end  of  good 
things.  It  ate  one  spider.  Its  mandibles  continued  toward  the  limit 
of  their  working  hours  and  came  bump  into  the  second  spider.  The 
stimulus  was  renewed,  and  its  jaws  commenced  to  work  again,  event- 
ually dragging  the  unfortunate  larva  into  death  at  the  hands  of  in- 
digestion. 

Thus  we  see  the  reason  for  hard  and  fast  rules  among  insects.  They 
are  entirely  dependent  upon  them  for  their  existence.  Even  so  slight 
a  variation  as  my  experiment  provided,  proves  this  to  my  satisfaction. 
I  varied  the  rule  in  one  small  particular  with  the  result  that  the  larva 
was  led  unconsciously  to  its  own  destruction. 

To  go  back;  the  larva  upon  finishing  its  spider  rests  for  a  short 
period  before  commencing  its  cocoon.  This  rest  may  be  necessary 
because  there  is  nothing  else  to  be  done  until  the  spinning  fluid  of 
which  the  cocoon  is  to  be  made,  commences  to  flow.  Once  started,  a 
network  of  strands  is  thrown  across  the  cell.  They  pass  for  the  most 
part  under  the  spinner  so  that  the  grub  rests  upon  a  net,  stretched 
midway  between  the  top  and  bottom  of  the  chamber.  Later,  upon 
this  preliminary  support,  a  neat  tubular  cocoon  is  spun.  It  is  rounded 
at  both  ends,  grayish  yellow  in  color,  glossy  and  rather  transparent. 
It  measures  eight  by  seventeen  millimeters,  and  only  partly  fills  the 


THE   BLUE   HUNTRESS  75 

roomy  cell.  As  a  final  touch  the  interior  is  lightly  coated  with  a 
pale,  smooth  varnish.  The  cocoon  is  finished  in  two  days,  after  which 
the  larva  excretes  a  mass  of  waste  matter  in  one  end.  This  accom- 
plished, it  lies  quietly  awaiting  pupation,  which  follows  in  eight 
days. 

The  pupa  is  yellowish  white  and  beautifully  folded  so  that  its  re- 
markably long  posterior  legs  do  not  extend  beyond  the  tip  of  its 
abdomen.  Its  head  is  armed  with  four  spikes.  Upon  either  side  of 
four  of  the  six  abdominal  segments  there  is  a  "jack,"  or  protruding 
T-shaped  support,  and  protruding  from  the  opposite  sides  of  the 
lateral  segment  is  a  pair  of  club-shaped  appendages. 

At  first  I  took  these  strange  objects  to  be  the  remains  of  ancestral 
legs.  I  thought  them  inherited  rather  than  acquired  characters,  but 
continued  observation  of  the  pupa  within  its  cocoon  proved  the  con- 
trary. They  have  been  acquired  in  order  that  the  insect's  heavy  abdo- 
men may  be  kept  leveled  or  centered  within  the  cocoon,  no  matter 
how  it  is  shaken  about  or  turns  of  its  own  accord. 

This  is  very  important  to  the  insect.  It  is  not  that  the  pupa  would 
be  injured  by  contact  with  the  cocoon  wall,  but  rather  that  the  weight 
of  its  own  abdomen,  which  is  joined  to  the  remainder  of  its  body  by  a 
very  narrow  waist,  would  have  to  be  borne  by  the  creature's  tender 
legs.  In  such  a  case  they  would  become  partly  crushed  and,  owing 
to  their  great  delicacy  at  this  period,  would  not  develop  properly. 
When  the  legs  have  become  strong  and  have  received  their  steel-blue 
pigment,  all  the  supporting  appendages  shrivel  and  are  completely 
lost.  This  takes  place  three  days  before  the  huntress  emerges  from 
her  cocoon.  The  supports  are  inflated  with  a  watery  fluid  which 

disappears  as  soon  as  a  breach  occurs  in  the  pupal  skin.    One  mav  be 

P— 

cut  off  without  seriously  injuring  the  wasp,  but  the  removal  of  all 
causes  deformed  legs  owing  to  the  abdomen  sagging  upon  them. 


76  INSECT  BEHAVIOR 

Emergence  from  the  cell  as  a  perfect  insect  takes  place  twenty- 
one  days  after  pupation.  If  the  parent  wasp  lived  she  might  witness 
the  home  building  of  her  children,  thirty-eight  days  after  she  de- 
posited them  as  eggs  in  cells  of  her  own  workmanship. 


A  cabbage  butterfly  depositing  an  egg 

This  common  white  insect  is  responsible  for  enormous  annual  loss,  its  offspring  destroying  great  quantities  of 
cabbage  throughout  the  summer  months.    Like  many  of  our  pests  it  is  an  introduced  species 


CHAPTER  -IX 

CONTROLLED    PUPATION 


1 


"^HERE  is  a  tree  in  the  Guiana  forest  which,  for  lack  of  a 
better  name,  I  call  the  vermilion-nut.  This  tree  ranks  high 
in  the  scale  of  giants.  It  towers  above  one,  reaching  more 
than  a  hundred  feet  above  the  forest  floor,  where  it  throws 
out  its  rather  flattened  boughs  that  bear  a  thick  mass  of  foliage,  and 
in  April,  a  vermilion  fruit.  This  fruit  is  lime-shaped,  two  inches 
in  length  by  one  and  one-quarter  inches  wide,  and  consists  of  a  moder- 
ately tough  pubescent  vermilion  shell,  guarding  the  soft,  greenish 
inner  pulp  that  surrounds  the  true  nut.  The  pulp  is  soft  and  quite 
sweet,  but  incipient,  and  the  nut  is  as  hard  as  a  fresh  almond  and 
slightly  over  twice  as  large.  Even  to  botanists  its  name  is  unknown. 

Troups  of  howling-monkeys  make  daily  visits  to  these  trees,  gorg- 
ing themselves  for  hours  on  the  juicy  pulp  and  throwing  the  shells, 
bearing  their  teeth  marks,  to  the  ground  below.  One  must  either  lie 
upon  the  back  or  suffer  a  cramped  neck  to  observe  them  feeding  in 
the  top-most  branches.  Even  then  they  are  often  screened  from  one's 
sight  by  the  masses  of  heavy  foliage  that  characterize  the  vermilion- 
nut. 

Other  animals  find  the  food  to  their  liking  also.  Agouti,  smaller 
species  of  monkeys,  and  a  host  of  wild  bees  feed  daily  beneath  the 
everlasting  twilight  of  these  branches.  One  might  spend  a  year 
studying  the  creatures  that  feed  upon  the  fruit,  which  is  often  scat- 
tered abundantly  among  the  rotting  vegetation  on  the  ground  for  a 
hundred  feet  in  every  direction. 

In  the  latter  part  of  April,  I  came  upon  a  band  of  howlers  feast- 

77 


78  INSECT   BEHAVIOR 

ing  in  one  of  these  trees.  They  were  easily  one  hundred  and  twenty- 
five  feet  from  the  ground,  yet  quite  unconscious  of  the  dizzy  height, 
they  reached  here  and  there  for  the  fruit,  seldom  clinging  to  the 
branches  with  other  than  the  hind  legs.  They  ate  with  great  relish 
and  greed,  plucking  far  more  than  they  could  possibly  eat.  Conse- 
quently many  nuts  were  dropped  quite  untouched,  and  wasted. 
Curious  as  to  the  quality  of  the  fruit,  I  picked  one  up  and  split  it 
apart.  To  my  surprise  it  contained  eleven  light  yellow  maggots,  that 
writhed  about  actively  and  tried  to  escape  from  their  late  prison. 
They  had  eaten  the  soft  pulp  entirely  away,  leaving  only  a  mass  of 
brown  excreta  and  the  inner  nut,  which  was  free  and  rattled  about 
when  I  replaced  the  shell  which  had  been  cut  away.  Thus,  by  chance, 
I  discovered  the  subject  of  this  chapter  in  its  strange  cradle  among 
the  tree-tops,  where  it  has  doubtless  fed  in  its  larval  state  since  the 
first  vermilion-nut  blossomed  in  the  branches  of  its  parent  This  is 
a  new  species  of  fly  belonging  to  the  family  Trepetidae,  and  the  genus 
Spilographa. 

When  and  how  the  mature  insect  deposits  her  egg  within  the  nut 
is  beyond  me.  It  would  be  necessary  to  live  in  the  loftiest  branches 
to  ascertain  such  a  fact.  One  glance  at  a  vermilion-nut  tree  would 
stand  as  evidence  of  its  infeasibility.  One  thing  we  do  know;  the 
insect  is  a  fly,  as  shown  by  the  larva,  a  typical  fly  maggot,  with  eleven 
segments,  counting  the  head.  It  tapers  from  a  well-rounded  segment 
at  the  posterior  end,  almost  to  a  point  at  the  head,  which  is  supplied 
with  two  hooks  turned  downwards  like  the  claws  of  a  cat.  It  is  trans- 
parent yellowish  white  and  through  its  entire  body  one  may  trace  a 
pair  of  respiratory  tubes  with  one  set  of  openings  in  the  head  and 
the  other  in  the  last  segment  of  the  body.  These  orifices,  two  in  front, 
two  behind,  stamp  the  creature  as  a  young  or  larval  fly. 

The  eggs  are  probably  deposited  when  the  fruit  is  still  soft  and 
immature  or  perhaps  the  scent  of  the  tree's  blossoms  beckons  to  the 


CONTROLLED    PUPATION  79 

insect.  I  can  but  surmise.  Later  the  eggs  give  place  to  tiny  wiggling 
larvae,  whose  movements  depend  upon  contractions  of  their  muscles, 
for  they  are  devoid  of  feet.  They  feast  like  gluttons  upon  the  nascent 
flesh  of  the  ripening  fruit  until  it  comes  time  to  pupate. 

From  what  we  know  of  many  other  flies,  we  have  seen  that  it  is 
natural  for  them  to  pupate  within  the  ground,  or  at  least  in  a  position 
from  which  they  may  work  their  way  to  the  light  of  day  when  nature 
has  transformed  them  into  perfect  insects.  The  larval  flesh  fly  bur- 
rows below  her  carrion  to  transform  in  the  damp  soil  beneath,  the 
house  fly  in  its  bed  of  manure  finds  escape  an  easy  matter,  the  mosquito 
transforms  in  the  water,  but  what  of  our  flies  born  within  a  tough- 
shelled  nut  in  the  highest  forest  branches?  How  are  they  to  release 
themselves  from  such  a  prison  after  the  feast  is  over?  As  we  have 
seen,  they  reach  the  ground  by  falling,  when  the  nut  is  plucked  by 
some  roaming  monkey,  or  as  it  falls  anyway  when  ripe,  carrying  its 
living  burden  earthward.  But  that  is  not  answering  the  question.  The 
larvae  must  burrow  into  the  forest  soil  to  transform  and  issue  suc- 
cessfully as  a  perfect  insect.  How,  then,  is  this  feast  accomplished? 

The  nut  which  I  cut  open  contained  eleven  larvae.  They  appeared 
to  be  full  grown  and  ready  to  pupate,  at  any  rate,  there  was  no  more 
pulp  left  for  them,  and  if  they  were  hungry  they  must  eat  again 
that  which  had  been  digested  once.  No,  they  simply  wiggled  about 
frantically  as  though  searching  for  an  opening  and  swarmed  to  the 
hole  I  had  cut. 

I  remove  two  of  them  to  tubes  of  soil  slightly  dampened.  The 
remainder  are  locked  once  more  in  their  prison.  In  the  tubes  con- 
ditions are,  as  nearly  as  I  can  make  them,  like  those  of  the  forest  floor. 
The  larvae  move  here  and  there  from  fright  in  their  new  environ- 
ment for  a  minute  or  two,  but  presently  one  thrusts  its  pointed  head 
into  the  soil  and  commences  to  burrow.  Soon  it  is  followed  by  the 


8o  INSECT   BEHAVIOR 

other  larvae  in  their  respective  tubes.     In  twenty  minutes  all  have 
disappeared  below  the  surface. 

Two  days  later  I  remove  the  material  from  the  tubes  in  search  of 
the  larvae.  They  have  burrowed  slightly  over  half  an  inch  below  the 
surface  and  all  have  transformed  into  little  yellow  kegs  with  ten  red 
hoops  running  around  them.  Under  the  lens  these  hoops  appear  to 
be  tiny  bands  of  stitches  like  those  in  the  cover  of  a  baseball.  In 
these  pupae  we  have  convincing  evidence  that  our  fly  naturally  trans- 
forms below  the  ground,  especially  so  in  view  of  the  fact  that  the 
larvae  left  within  the  nut  are  still  strictly  larvae  in  every  sense  of  the 
word. 

I  remove  two  more  of  the  imprisoned  ones  from  the  nut  to  freshly 
prepared  tubes  of  earth.  Two  days  later  I  have  the  same  result  from 
my  experiment.  Those  within  the  tubes  have  transformed  to  pupae, 
but  those  still  imprisoned  in  the  vermilion-nut  remain  in  the  maggot 
form.  I  keep  the  prisoners  in  their  cell  from  April  2Oth  until  the 
1 2th  of  May.  Still  there  is  no  change  from  the  larval  form,  yet  any 
day  I  remove  one  to  a  tube  of  earth  and  forty-eight  hours  later  re- 
cover it  as  a  pupa!  It  is  a  strange  condition  indeed,  but  I  think  I 
see  its  significance. 

When  I  open  the  fruit  on  the  tenth  day  of  May,  I  note  that  the 
true  nut  within  has  sprouted  ever  so  slightly.  Each  day  the  cotyledons 
of  the  new  tree  are  swelling  within  the  shell  that  holds  them,  push- 
ing upwards  in  response  to  the  light  above.  Were  the  nut  lying  nat- 
urally upon  the  moist  floor  of  the  forest,  the  young  tree's  progress 
would  be  even  faster.  At  length  the  pressure  becomes  too  great  for 
the  nut's  outer  shell  to  bear.  It  yields  to  the  vortex  of  a  new  life, 
splits  open,  and  at  the  same  time  the  imprisoned  larvae  find  the  long- 
waited-for  exit  to  the  friendly  mould  of  the  forest. 

Here  is  a  condition  among  insects  previously  unknown  to  me.  It 
is  a  remarkable  adaptation  to  the  condition  of  the  creature's  strange 


- 


Male  and  female  paper-wasps  hatching  from  the  cells  of  a  nest,  in  July.    Enlarged  four  times 


Paper-wasp  worker  with  unusually  large  pellet  of  wood-pulp  preparing  to  enlarge  the  nest.    Enlarged  four  times 


CONTROLLED    PUPATION  81 

habitat,  that  has  brought  about  a  deviation  from  the  rule.  In  short, 
the  young  flies  may  hasten  or  postpone  pupation  at  will!  I  would 
have  hesitated  to  set  forth  such  a  statement,  even  as  a  remote  possi- 
bility, were  it  not  for  my  experiments  that  cannot  be  denied.  One 
learns  to  expect  the  unexpected  in  nature,  but  who  would  go  so  far 
as  to  accuse  her  of  running  even  so  tiny  a  creature  as  this  nascent 
fly,  without  a  schedule?  She  is  forced  to  surrender  here  to  conditions 
self-imposed.  If  her  children  within  the  vermilion-nut  lie  impris- 
oned without  food  for  a  fortnight  or  more,  it  matters  not.  When  re- 
lease comes  they  are  none  the  worse  for  their  experience.  If  they 
are  spilled  roughly  on  the  ground  from  a  freshly  broken  nut  a  month 
before  their  brothers,  so  much  the  better.  They  have  no  set  time  for 
pupation.  They  will  become  flies  just  the  same.  Thus  Nature  has 
endowed  them  with  ability  to  meet  successfully,  the  strange  circum- 
stances in  which  she  herself  has  placed  them. 

Let  us  see  what  has  happened  to  the  larva  that  has  burrowed  be- 
neath the  surface  of  the  ground.  Why  must  such  an  active  creature 
entomb  itself  again  upon  being  liberated  from  its  original  prison? 

Unlike  ourselves,  animals  or  birds,  insects  pass  through  a  series  of 
stages,  one  might  say,  almost  by  jumps.  At  first  we  have  an  egg,  quite 
helpless,  but  deposited  with  due  care  and  forethought  by  its  provident 
bearer.  In  a  day  or  so,  this  helpless  egg  has  become  a  ten-ringed 
maggot  with  a  head,  appendages  for  drawing  in  its  food  and  possessed 
of  a  primitive  but  efficient  set  of  organs.  It  is  not  an  actual  hatching 
as  we  see  it  in  a  hen's  egg  that  has  brought  this  strange  creature  into 
the  world,  but  a  fading  of  egg  into  maggot.  There  is  no  empty  shell 
when  the  process  is  finished,  no  specter  of  the  creature's  former  self. 
The  process  is  like  that  of  a  moving  picture,  which  fades  before  one's 
eyes  from  one  scene  to  the  next,  which  is  widely  different. 

In  its  newly  acquired  form,  the  insect  feeds,  as  we  have  seen,  upon 
the  vermilion-nut  pulp,  remaining  unchanged  except  in  size,  until 


82  INSECT   BEHAVIOR 

fate  releases  it  upon  the  moist  forest  floor,  when  with  a  haste  that  is 
almost  frantic  it  immediately  imprisons  itself  once  more,  this  time 
in  the  ground  wherever  it  chances  to  find  itself.  Forty-eight  hours 
later,  we  discover  it  as  a  tiny  yellow  keg,  banded  with  red  stitches, 
as  though  it  had  buried  itself  for  good  in  a  self-fashioned  coffin. 

Has  the  insect  become  so  accustomed  to  the  blackness  of  prison  life 
that  it  cannot  live  in  a  world  of  sunlight?  Must  it  live  the  life  of  a 
mole  because  it  has  only  once  seen  the  brightness  of  day?  No,  there 
is  a  far  deeper  reason  than  these,  that  sends  it  so  hastily  into  the 
ground.  It  is  about  to  undergo  its  last  and  greatest  transformation, 
one  during  which  it  will  be  once  more  utterly  helpless  against  the 
slightest  odds.  It  must  lie  very  still,  as  though  in  death,  lest  the 
beautiful  process  within  be  interrupted  and  the  design  shattered. 

Up  to  now,  the  insect  has  resembled  its  ancestral  family,  less  highly 
developed  worm-like  creatures  of  another  day.  Just  as  we  have  de- 
veloped from  less  perfect  creatures,  so  has  the  fly.  Within  the 
little  yellow  keg  a  wonderful  change  is  in  process. 

At  first  the  maggot,  so  recently  an  active  definite  creature,  is  seized 
upon  by  a  host  of  nature's  strangest  forces.  We  cannot  see  them  or 
give  them  any  definite  form.  Nevertheless  they  are  there,  like  a 
great  group  of  wreckers,  carpenters,  masons,  painters  and  decorators. 
The  larva  or  maggot,  the  ancestral  form,  is  torn  down  and  reduced 
to  a  disintegrated  mass  of  fluid.  From  this  utter  wreck  of  what  was 
so  lately  a  crawling,  organized  creature,  the  final  insect  is  resur- 
rected. From  old  tissues,  new  ones  spring,  from  what  was  old  and 
out  of  date,  a  more  modern  creature  is  erected.  The  yellow  keg  is  no 
longer  a  coffin,  but  a  factory  wherein  a  host  of  raw  materials  are 
to  be  transformed  into  the  finished  product! 

The  process  is  comparable  to  tearing  down  an  old-fashioned  house 
and  erecting  a  modern  one  on  the  old  foundations.  Much  of  the 
old  material  is  used,  and  that  which  must  be  replaced  by  new,  is 


CONTROLLED    PUPATION  83 

burned  or  otherwise  disposed  of.  So  it  is  with  the  tissues  of  the 
maggot.  From  the  old  house  we  save  the  plumbing,  the  wiring  and 
the  kitchen  range,  which  corresponds  in  the  maggot  to  the  repro- 
ductive glands,  the  nervous  system  and  the  heart,  which  are  left  in- 
tact, or  at  most  altered  and  attended  to. 

At  length  it  becomes  time  for  the  painters  and  decorators.  Nature 
employs  a  vast  army  of  these.  In  the  keg,  after  ten  days,  the  milky 
white  and  partly  transparent,  but  otherwise  perfect  insect  commences 
to  receive  its  color.  It  appears  first  in  the  eyes  with  an  influx  of 
emerald  green  pigment  studded  with  golden,  microscopical  dots, 
which  are  followed  in  forty-eight  hours  by  the  appearance  of  black 
patterns  upon  the  legs  and  wings,  due  to  more  or  less  dense  hairs 
upon  these  appendages  into  which  the  color  gradually  flows.  Upon 
the  back  of  the  head  there  is  a  pattern  of  hairs  and  another  of  longer 
ones  upon  the  thorax,  while  the  abdomen  likewise  suddenly  appears 
clouded  with  pubescence.  Further  than  this  no  ground  color  or 
markings  can  be  seen,  owing  to  the  color  being  much  like  the  shell 
of  the  keg  itself. 

In  another  forty-eight  hours,  fourteen  days  after  pupation,  the  fly 
emerges  by  splitting  the  head  of  the  pupal  keg  in  two  equal  parts. 
This  is  a  simple  operation,  as  the  shell  is  not  too  substantial,  but 
the  new-born  fly  has  yet  another  task,  before  it  will  be  free.  It  has 
yet  to  dig  a  passage  from  its  tomb  to  the  light  of  day.  It  must  be 
done  quickly,  lest  the  wings  fill  and  dry  too  small  and  their  use- 
fulness be  lost. 

For  this  purpose  the  insect  is  supplied  with  a  battering  ram,  which 
protrudes  between  the  eyes  at  birth  from  the  pupal  case.  It  is  a  trans- 
parent sack-like  appendage  which  may  be  expanded  or  contracted 
at  will  by  the  fly.  It  contains  no  apparatus  of  any  kind,  but  is  ap- 
parently the  forehead  of  the  insect  capable  of  expansion.  To  watch 
the  operation  of  this  strange  appendage  is  remarkable.  First,  it 


84  INSECT  BEHAVIOR 

swells  like  a  toy  balloon  when  air  is  blown  into  it,  until  it  protrudes 
two  or  more  millimeters  in  front  of  the  insect's  head,  pushing  the 
sand  or  dirt  in  front  of  it  as  it  increases.  This  is  followed  by  a 
rapid  deflation  of  the  ram,  which  leaves  an  indentation  into  which 
the  fly  struggles  with  great  effort.  Now  the  first  operation  is  re- 
peated, the  second  indentation  made  and  again  the  insect  wedges  it- 
self into  it.  Thus,  after  an  hour,  if  the  fly  is  fortunate,  it  reaches  the 
surface  of  the  ground,  where  it  rests  for  a  time  to  recover  its  strength, 
before  launching  into  a  new  and  sunlit  world  once  more  to  search  out 
the  vermilion-nut,  this  time  as  a  nursery  for  its  own  offspring. 


; 

>    j.*T!    C* 


CHAPTER  X 

CAXXIBAL  WASPS 

Philanthus  gibbosus 

IN  the  glaring  July  sun,  seething  in  a  dizzy  sea  of  rising  heat 
waves,  the  cannibal  wasps  have  built  their  city.  The  tennis 
court,  but  let  us  forget  the  human  world,  in  the  eyes  of  the  in- 
sects, is  a  great  sandy  plateau,  dotted  in  a  hundred  places,  with 
tiny  hills  of  sand  that  mark  the  excavations  of  their  metropolis. 

It  is  a  barren  land  where  mud  huts  bleach  in  a  sun  that  knows  no 
mercy  and  yet  strangely  enough,  where  the  lives  of  its  inhabitants  are 
filled  with  endless  work  and  gigantic  energy. 

If  you  can  imagine  a  tropical  climate  without  trees  and  where  the 
creatures  that  people  it  possess  greater  energy  than  those  of  a  temper- 
ate zone,  then  you  will  have  a  fair  idea  of  the  conditions  existing  in 
the  topsy-turvy  land  of  the  cannibal  wasp.  * 

The  insects  are  gregarious,  but  a  separate  burrow,  or  mine,  is  con- 
structed by  each  female  belonging  to  the  general  colony. 

These  tunnels  are  the  homes  of  the  wasps,  mines  in  which  the 
domestic  duties  are  carried  on.  They  are  excavated  in  various 
fashions,  twisting  and  turning  according  to  the  conditions  of  the 
ground.  In  all,  the  burrows  may  reach  twenty-four  inches  in  length, 
terminating  in  an  elongated  cell  or  chamber,  twice  the  width  of 
the  passage  leading  to  it.  One  or  two  short  branches,  also  terminating 
into  roomy  chambers,  may  be  found  at  various  points  near  the  end 
of  the  shaft.  These  cells  are  nurseries  where  the  young  wasps 

are  reared  and  of  which  we  will  hear  more  later. 

85 


86  INSECT  BEHAVIOR 

Beside  the  entrance  hole  to  the  burrow,  a  second  tunnel,  about  two 
inches  in  length,  is  sometimes  excavated,  which  serves  as  a  sentry 
box,  in  which  the  insect  rests  and  guards  the  entrance  to  the  main 
nest.  It  is  amusing  to  see  a  wasp  from  the  colony  lose  its  bearings 
and  attempt  to  enter  the  wrong  nest,  when  the  rightful  owner  rushes 
from  her  sentry  box  and  pounces  upon  the  intruder.  Then  amid 
loud  buzzings,  which  are  doubtless  oaths  of  a  fearful  nature,  the  two 
roll  about  until  the  intruder  is  driven  off. 

But  let  us  go  back  to  the  building  of  the  burrow,  which  is  a  gigantic 
task  for  so  small  a  creature.  She  must  be  engineer,  laborer,  drill  and 
steam  shovel  if  her  race  is  to  survive,  and  this  is  no  small  burden  for 
such  delicate  shoulders  to  bear. 

But  in  a  wasp  city  there  is  never  a  complaint,  never  a  strike  for 
higher  wages,  but  always  a  superb  spirit  of  altruism  and  a  wealth  of 
strength  that  defends  the  race  against  extinction.  In  a  way,  instinct 
triumphs  over  intelligence  here. 

At  the  entrance,  one  finds  a  heap  of  dirt  excavated  from  the  bur- 
row, which  is  carefully  piled,  in  order  that  it  will  not  run  back 
into  the  doorway  and  double  the  labor  of  the  well-planned  dwelling. 

On  arriving  at  her  tunnel,  the  miner  alights  at  the  far  edge  of  the 
sand  heap.  From  here  she  moves  rapidly  forward,  kicking  the  sand 
back  the  while,  thus  forming  a  distinct  trough  leading  to  the  hole. 
This  clever  method  of  approach  is  to  prevent  sand  from  rolling  into 
the  nest,  which  would  be  the  case  should  she  come  blustering  directly 
into  the  entrance. 

To  compare  the  weight  of  the  sand  heap  with  that  of  the  wasp 
will  be  interesting.  For  this  purpose  the  diggings  from  an  average 
tunnel  are  scooped  up  and  placed  upon  a  delicate  scale.  It  registers 
about  two  ounces.  Now  we  place  the  wasp,  on  the  scales  and  find 
that  its  weight  in  the  same  measure,  is  one  four-hundredth  part  of  one 
ounce. 


ie  cannibal  and  her  diggings.     In  excavating  her  tunnel,  the  insect 
sand  eight  hundred  times.    Life  size.    From  a  mounted  specimen. 


A  complete  model  of  a  cannibal  wasp's  burrow.  This  model,  secured  by  pouring  molten 
lead  into  a  nest,  clearly  illustrates  the  shape  of  the  tunnel  with  its  extra  tube  cr  sentry 
box  at  the  left.  One-third  natural  size. 


CANNIBAL  WASPS  87 

In  other  words,  the  wasp  in  excavating,  has  removed  her  weight 
in  sand  eight  hundred  times.  Now  let  us  compare  her  work  in  pro- 
portion with  that  which  a  man  would  have  to  do  to  accomplish  a 
similar  feat.  Taking  a  man  weighing  one  hundred  and  fifty  pounds 
and  multiplying  by  eight  hundred,  which  are  the  same  figures  used 
in  the  case  of  the  wasp,  we  get  one  hundred  and  twenty  thousand 
pounds,  or  sixty  tons.  The  insect  then  removes  the  equivalent  of 
sixty  tons  of  earth  to  make  her  nest.  This  she  does  with  no  tools 
except  her  forelegs,  and  the  gigantic  task  is  completed  in  four  days. 
Had  we  the  same  strength  and  endurance,  the  Panama  Canal  might 
have  been  completed  in  a  week  or  two! 

When  the  excavation  is  finished,  the  insect  at  once  turns  her  atten- 
tion to  storing  the  subterranean  cells  with  proper  food  for  her  off- 
spring, and  here  we  shall  bring  to  light  the  cannibalistic  instincts  of 
these  mining  wasps. 

The  majority  of  the  solitary  wasps  feed  their  young  upon  inch- 
worms,  spiders,  flies,  or  insects  of  an  entirely  different  order  from 
themselves.  But  not  so  the  miners;  who  in  some  cases  deliberately 
hunt  out  members  of  their  own  family,  paralyzing  them  with  a  drive 
of  the  sting  and  dragging  them  into  the  tunnels  for  their  young  to 
feast  upon! 

As  many  as  a  half-dozen  victims  may  be  packed  into  a  single  cell. 
Tiny  humble  bees,  green  and  blue  flower  bees,1  and  sometimes  unfor- 
tunate miners  that  have  been  executed  for  daring  to  place  a  foot  in 
the  wrong  doorway. 

In  a  week  the  cells  are  packed  from  end  to  end  with  victims  of  the 
cannibal's  pitiless  nature.  The  array  is  more  gruesome  than  the 
corpses  lying  in  a  morgue,  yet  the  insect  gloats  over  her  industry  of 
murder,  rushing  eagerly  in  to  inspect  the  contents  of  the  cell,  over 

1  Ceratinadae. 


88  INSECT  BEHAVIOR 

and  over,  before  laying  her  glistening  oily  yellow  egg  upon  the  mass 
of  helpless  flesh. 

In  two  days  the  young  cannibals  wriggle  from  the  eggs,  footless, 
whitish  maggots  and  helpless  against  the  slightest  odds.  Yet  nature 
has  provided  for  them  in  such  a  manner  that  they  may  attach  them- 
selves to  superior  creatures,  who  must  lie  motionless  and  submit  to 
their  suckling  mouths  until  the  last  cells  of  life  pass  into  the  bodies 
of  the  cannibals! 

A  single  egg  is  laid  upon  the  contents  of  each  cell,  and  normally 
seven  days  are  required  by  the  young  to  gorge  themselves  into  a  state 
of  torpor  which  lasts  until  the  following  spring.  Then  a  wonderful 
transformation  takes  place.  The  motionless,  fatty  larva  commences 
to  assume  a  definite  form. 

Within  its  milky  skin,  disintegrated  tissues  and  layers  of  cells  have 
been  whirled  by  nature's  magic  hand  into  definite  parts  and  organs 
of  the  nascent  creature.  Legs  unfold  like  budding  leaves,  a  narrow- 
ing of  the  waist  separates  the  thorax  from  the  abdomen  and  delicate 
wings  "sprout"  from  the  center  of  the  back. 

Then  comes  color,  darkening  the  head  and  thorax  and  throwing 
yellow  bands  about  the  abdomen,  and  finally  comes  the  gift  of  motion, 
which  leaves  only  a  layer  of  earth  between  the  cannibal,  the  sun- 
light and  another  generation  of  innocents  to  become  her  victims. 

Crimes  cannot  always  go  unpunished.  There  must  be  justice,  even 
in  the  insect  world.  This  slaughter  of  the  innocent  flower  bees  must 
be  avenged  or  regulated  and  nature's  reprisal  is  cunning  and  severe. 

There  is  another  wasp-like  creature,  a  true  fly  in  reality,  that  plays 
her  part  in  this  gruesome  drama.  Nature  has  given  her  a  flight  that 
resembles  a  wasp's,  to  afford  protection  from  minor  enemies,  but  this 
is  not  the  most  remarkable  of  her  gifts.  It  is  her  mission  in  life  to 
hold  these  cannibals  of  the  insect  world  in  check,  and  she  performs 
her  duty  with  precision. 


A  wasp  of  the  sphecid's  size  compared  to  a  small  rove  beetle.  Although  four  times  life  size  in  the  picture, 
this  insect  is  a  formidable  creature  in  its  natural  size.  Note  the  tongs  upon  the  legs  which  in  the  sphecid 
assist  in  carrying  the  prey. 


~ 


-: 


Sphecid  wasp  dragging  a  paralyzed  cicada  to  her 
burrow,  after  the  homeward  flight. 


Common   cicada,   upon  which  the  sphecid  wasp 
preys. 


CANNIBAL  WASPS  89 

While  the  cannibal  is  abroad  in  search  of  a  victim,  this  creature, 
which  we  will  call  the  checker-fly,1  because  of  the  peculiar  pattern 
upon  her  abdomen,  takes  her  life  in  her  hands  and  slips  into  the 
den  of  the  murderer. 

Now  to  understand  this  action  we  must  first  examine  a  checker- 
fly  in  the  laboratory.  Dissection  brings  a  wonderful  fact  to  light. 
In  the  fly's  abdomen  we  find  no  eggs,  as  one  might  expect,  but  in  their 
place  ten  living  larvae!  The  microscope  shows  them  to  be  whitish 
maggots  clustered  together  in  a  ring,  and  through  their  transparent 
bodies  one  may  see  the  expanding  and  contracting  of  embryonic 
muscles. 

The  checker-fly  then  gives  birth  to  her  young  alive!  But  why? 
She  is  a  lowly  rung  in  the  ladder  of  insect  life,  while  the  cannibal, 
a  member  of  the  highest  order  of  insects,  is  gifted  with  nothing  more 
unusual  than  egg  laying! 

The  explanation  is  simple.  When  the  checker-fly  enters  the  bur- 
row, she  heads  straight  for  the  cell,  in  order  to  bear  her  young  upon 
the  meat  stored  up  by  the  wasp  for  her  own  offspring.  Thus  she 
saves  herself  the  trouble  of  providing  a  home  and  food  for  them. 

We  must  know  that  the  wasp  is  nearly  four  times  as  large  as  the 
fly  and  greatly  superior  in  strength.  Now  should  the  fly  and  the  wasp 
both  lay  eggs,  the  ultimate  result  would  be  at  once  apparent. 

The  eggs  of  both  insects  would  hatch  about  the  same  time,  but 
the  young  cannibals  would  soon  grow  much  larger  than  the  flylets. 
The  strongest  individuals  survive,  and  were  it  not  for  nature's  care 
in  such  matters,  the  young  checker-flies  would  perish. 

What  takes  place  is  plain.  The  parent  fly  bears  her  young  alive 
and  they  start  at  once  feeding  and  groxving  within  the  cell.  In  two 
days  the  wasp's  eggs  hatch,  but  the  young  checker-flies  have  now 

1 A  species  of  Tachininae.  This  sub-family  includes  some  of  the  most  highly 
beneficial  species  of  flies,  such  as  the  Red-tailed  Tachina  (Winthemia  4-pustulata), 
a  parasite  of  the  Army  worm. 


90  INSECT  BEHAVIOR 

gained  sufficient  strength  and  size  to  push  aside  and  starve  the  new- 
born wasps! 

Thus  nature  modifies  the  birth  rate  of  the  cannibals,  sending  these 
checkered  enemies  to  destroy  them,  lest  some  day  they  exterminate 
the  useful  little  flower  and  humble  bees,  whose  mission  in  life  it  is 
to  blend  the  pollens  of  a  billion  blossoms  and  make  our  world  a 
land  of  plenty. 


Comparative  wing  expanse  of  cicada  (\eh)  ar>d  sphecid  wasp  (right) 


Hole  in  cicada  through  which  the  larval  sphecid 
entered  its  host 


Young  sphecid  wasp  two  days  old  feeding  upon  a 
paralyzed  cicada 


CHAPTER  XI 

THE  SPHECID'S  DUTY 

Spheclus  speciosus 

WHEN  July  has  blended  its  last  hot  days  into  August 
and  the  air  vibrates  with  the  monotonous,  irritating 
song  of  the  cicada,  it  is  then  that  one  member  of  the  in- 
sect world,  the  great  golden  digger,  is  hardest  at  work. 
Though  the  most  formidable  member  of  our  eastern  American  wasps, 
being  the  largest,  and  possessed  of  a  most  powerful  sting,  it  is  perhaps 
more  peaceable  and  less  easily  irritated  than  many  of  the  smaller 
members  of  the  Hymenoptera  family. 

Solitary  wasps,  of  which  the  golden  digger  is  one,  are  invariably 
more  peaceful  and  easier  to  work  with  than  social  species,  for  a  very 
simple  reason.  Solitary  individuals  are  almost  all  preying  species, 
creatures  who  require  the  services  of  their  stings  in  paralyzing  their 
victims.  They  reserve  their  poison  and  the  energy  required  in  in- 
jecting it,  until  it  is  time  to  gather  provender  for  the  coming  genera- 
tion of  their  kind.  Such  wasps  sting  in  self  protection  only  when 
captured,  and  scarcely  ever  in  defense  of  their  nests. 

Social  wasps  and  bees  seldom,  if  ever,  sting  their  prey  and  many 
of  them  are  not  even  of  predatory  habits.  The  sting  is  therefore  un- 
necessary in  capturing  or  preparing  food  for  their  offspring  and  is 
used,  as  we  know,  chiefly  in  defense  of  the  nest,  which  is  the  common 
property  of  a  number  of  individuals. 

The  sphecid's  service  to  mankind  in  killing  countless  numbers  of 
the  noxious  cicadas  makes  this  great  wasp  a  popular  one  with  those, 

all  too  few,  who  understand  its  highly  beneficial  function. 

91 


92  INSECT  BEHAVIOR 

As  in  all  insects,  the  wasp's  first  vital  duty  upon  leaving  its  cocoon 
is  to  mate  and  deposit  her  eggs,  which  in  due  time  are  to  bring  forth 
the  diggers  of  the  following  season.  Her  life  story  is  most  interesting. 

Towards  the  middle  of  the  day,  when  the  cicadas  are  singing  in 
every  tree,  the  sphecid  may  be  seen  flying  swiftly  to  a  spot  from 
whence  a  song  is  issuing.  For  a  minute  she  disappears  among  the 
foliage,  then  suddenly  the  song  ceases  abruptly,  giving  place  to  a 
cry  of  agony  and  fright.  The  wasp  has  seized  the  unsuspecting 
cicada,  and  its  terrible  sting  has  been  driven  in,  instantly  paralyzing 
and  throwing  the  unfortunate  insect  into  a  comatose  condition,  from 
which  it  never  recovers. 

The  wasp  and  cicada  will  often  fall  to  the  ground  together, 
struggling  violently,  the  ill-fated  bug  giving  vent  to  discordant  death 
cries.  From  here  the  wasp  carries  its  burden  to  the  nest,  which  is 
often  a  difficult  object  to  accomplish.  The  cicada  is  heavier  than 
the  wasp  herself,  which  is  a  condition  rarely  met  with  among  the 
preying  Hymenoptera,  and  to  carry  the  victim  to  the  burrow  often 
requires  much  time  and  patience  on  the  part  of  the  sphecid. 

If  the  wasp  and  cicada  fall  from  the  foliage  of  a  tall  tree,  all  goes 
well.  The  wasp  recovers  before  reaching  the  earth  and  flies  to  the 
nest  without  difficulty.  Usually,  however,  the  two  strike  the  ground 
in  a  noisy  struggle,  where  the  sphecid  accomplishes  her  work  of 
paralyzing  the  cicada,  often  in  a  tiny  cloud  of  dust.  When  this 
happens  the  wasp  cannot  lift  her  dead  weight  victim  into  the  air. 
Try  as  she  may,  the  precious  meat  will  not  budge  from  the  earth  and 
one  wonders  how  the  journey  to  the  nest  will  be  accomplished. 

It  has  been  stated  that  in  such  a  case,  the  wasp  drags  the  cicada 
overland,  but  this  I  have  found  to  be  untrue.  The  sphecid's  course  is 
very  simple  and  interesting. 

She  drags  her  burden  to  the  nearest  tree,  mounts  to  a  distance 
of  twenty  feet  or  more  and  from  this  lofty  perch  launches  herself 


Queen  paper-wasp  in  the  act  of  depositing  an  egg  which  may  be  seen  just  emerging  from  the  insect's  body 

Enlarged  seven  times 


o 

fe 


THE  SPHECID'S  DUTY  93 

into  the  air  with  the  cicada,  which  is  now  quiet  and  helpless.  At  first 
she  tumbles  like  a  wounded  aeroplane,  but  at  length  recovers,  rights 
herself  and  thus  gains  sufficient  momentum  to  fly  without  halt  to 
the  nest. 

The  nest  consists  of  a  sloping  burrow,  continuing  under  the  ground 
for  about  eight  inches  in  a  straight  line.  A  sharp  turn  is  usually  made 
at  this  point  and  the  tunnel  carried  on  for  twelve  inches  more.  At 
the  extreme  end  there  is  an  elongated  cell,  large  enough  to  hold  a 
single  cicada.  Branches  from  the  main  passage  are  often  excavated, 
and  occasionally  one  of  the  cells  at  the  ends  of  these  branches  will 
contain  two  cicadas.  It  has  been  stated  that  these  cells  containing 
two  victims  bring  forth  much  larger  wasps  than  those  containing  one, 
and  as  the  female  wasp  is  much  larger  than  the  male,  it  was  thought 
by  a  well-known  entomologist  that  the  cells  containing  the  greater 
amount  of  provisions  produced  the  females  and  those  containing  a 
lesser  amount,  the  males.  However,  it  does  not  seem  probable  that 
an  insect  possesses  the  power  of  distinguishing  her  eggs  to  the  extent 
of  telling  which  are  to  bring  forth  the  males  and  which  the  females. 

When  a  cell  contains  its  store  of  cicada  meat,  a  single  whitish  egg 
is  laid  under  the  middle  leg  of  the  victim.  After  this  the  burrow  is 
closed  up  by  the  wasp  and  her  duties  are  finished.  The  eggs  hatch 
in  two  days,  and  the  larvae,  as  the  young  grub-like  sphecids  are  called, 
start  at  once  to  suck  the  nourishment  from  the  bodies  of  the  cicadas, 
later  entering  the  hosts'  bodies,  where  they  attain  full  size  in  seven 
or  eight  days. 

Now  a  rough  cocoon  is  spun  by  each  inside  of  its  respective  cicada, 
wherein  it  later  transforms  to  a  pupa,  the  stage  corresponding  to  the 
chrysalis  of  a  butterfly. 

In  this  soft,  helpless  condition  it  remains  all  through  the  winter, 
until  the  following  summer.  Then,  when  the  cicadas  are  calling 
once  more,  the  long  buried  cocoon,  from  which  the  hollow  shell  of 


94 

host  has  long  since  rotted  away,  splits  open.  Out  crawls  the  powerful 
giant  wasp,  she  brushes  herself  thoroughly  and  waits  for  strength  to 
dig  her  way  out. 

In  a  few  hours  she  has  made  her  way  laboriously  to  the  surface  of 
the  ground.  Here,  all  laden  with  mud  and  the  sweat  of  her  effort, 
she  cleans  and  scrubs  and  rubs  the  dirt  from  her  limbs.  She  draws 
her  feet  through  her  mouth  and  with  this  droll  fluid  polishes  her 
eyes.  Last,  she  scrapes  her  feelers  clean,  curls  them  back  and  forth, 
spits  upon  them,  rubs  them  until  they  shine  like  metal.  Having  thus 
made  her  toilet,  she  is  off,  expert  of  wing  at  her  virgin  flight.  She 
goes  in  a  straight  line  out  of  sight,  in  search  of  a  male  to  become  her 
mate. 


Cells  of  a  paper-wasp's  nest,  showing  heads  of  young  insects,  and  silken  caps  spun  at  a  later  date.    Four  times 

life  size 


Unlike  the  large  globular  nests  of  the  hornets,  those  of  the  paper-wasp's  are  simply  masses  of  uncovered  cells. 

Life  size 


CHAPTER  XII 

THE  ORIGINAL  PAPER-MAKERS 

T~  p  ~"^HE  societies  of  the  paper  wasps,1  like  those  of  other  social 
g  insects  of  the  family,  consist  of  three  kinds  of  individuals, 

•  males,  females  and  workers.  The  colonies  only  exist  for  a 
single  season,  the  males  and  workers  dying  in  the  fall.  The 
females  or  queens  hibernate  and  each  starts  a  new  community  in  the 
spring.  The  queen  is  the  largest  in  the  colony  and  her  one  duty, 
after  the  first  few  weeks  of  spring,  is  egg  laying.  The  males  or 
drones  are  created  for  the  one  purpose  of  fertilizing  the  eggs  of  the 
queen  and  after  performing  this  duty  they  are  frequently  killed  and 
thrown  from  the  nest  by  the  workers.  These  so-called  workers  are, 
in  reality,  undeveloped  females,  who  are  unable  to  reproduce  in  a 
beneficial  way,  as  their  eggs  invariably  produce  drones.  Thus  they 
are  unable  to  assist  in  increasing  the  numbers  of  working  individuals 
in  the  colony  and  the  heavier  \vork  must  therefore  fall  upon  these 
otherwise  useless  members. 

Let  us  start  with  the  queen  mother,  the  only  survivor  of  last  year's 
colony,  who  has  safely  passed  through  the  winter  in  an  impregnated 
and  torpid  condition  and  who  must  now  lay  the  foundations  of  another 
great  insect  city. 

When  in  the  spring  she  lays  the  foundations  of  her  future  empire, 
she  has  not  a  single  worker  at  her  disposal,  and  with  her  own  hands 
and  teeth  she  must  lay  the  corner-stone  of  her  future  metropolis. 
She  must  herself  build  the  first  combs  and  produce  from  her  own 
womb  their  first  inhabitants,  which  in  their  infant  state,  she  must  feed 
and  educate  before  they  can  assist  her  in  the  great  design.  At  length, 

1  Polistes  pallipes. 

95 


96  INSECT  BEHAVIOR 

she  receives  the  reward  for  her  perseverance  and  labor;  and  from 
being  a  solitary  unconnected  individual,  in  the  summer  is  enabled  to 
rival  the  queen,  who  gave  her  birth,  in  the  number  of  her  children 
and  subjects,  and  in  the  empire  of  which  they  are  inhabitants.  Even 
at  this  time,  when  she  has  so  numerous  an  army  of  helpers,  the  in- 
dustry of  this  creature  does  not  cease',  but  she  continues  to  set  an 
example  of  diligence  to  the  rest  of  the  colony.  If  in  any  way  the 
queen  mother  perishes,  before  the  other  females  are  hatched,  the 
workers  lose  their  instincts,  cease  their  labors  and  die. 

The  number  of  females  in  a  paper  wasp  colony  is  quite  consider- 
able. They  are  hatched  about  the  latter  part  of  July  or  during  the 
first  part  of  August,  at  the  same  time  and  in  about  the  same  numbers 
as  the  males.  In  September  and  October,  they  fly  from  the  nest 
and  after  mating,  the  males  live  but  a  short  time.  Of  all  the  females, 
very  few  survive  the  winter  to  start  the  new  empires  when  the  vernal 
sun  brings  the  insect  world  to  life  again. 

To  the  workers  falls  the  entire  care  of  the  young  and  other  members 
of  the  colony.  They  must  not  only  supply  the  food,  which  consists 
of  honey  and  chewed-up  insects,  but  they  must  also  protect  the  nest 
from  outside  intruders.  These  neuters  must  be  ready  and  willing  at 
all  times  to  do  reconstruction  work  upon  the  rapidly  growing  nest. 
Almost  daily  there  are  new  cells  to  be  built,  walls  to  be  strengthened, 
openings  to  be  closed  and  all  manner  of  things  which  it  is  only  proper 
for  a  worker  to  do.  Of  all  these  operations  no  other  is  so  interesting 
as  the  process  by  which  the  wasp's  paper  is  made.  It  is  manufactured 
of  wood  pulp  or  other  ligneous  fiber,  which  is  scraped  by  the  worker 
from  old  weathered  boards,  fence  rails  and  other  unpainted  wood 
which  has  weathered  for  a  number  of  years.  I  once  found  a  pole 
which  supported  a  bird  house,  so  thoroughly  scraped  by  paper  wasps 
and  so  frequently  visited  by  them  that  it  was  kept  in  a  roughened 
condition  all  summer.  This  pole  must  have  supplied  the  pulp  for 


Cells  of  the  paper-wasp  with  caps  removed  to  show  heads  of  pupae  nearly  ready  to  emerge  as  perfect  insects. 

Greatly  enlarged 


THE  ORIGINAL  PAPER-MAKERS  97 

many  nests  in  the  neighborhood,  and  even  now  is  used  year  after  year 
by  insects  of  this  family. 

The  tiny  particles  of  wood  fiber  are  mixed  by  the  wasp  with  a 
glutinous  substance,  which  is  apparently  secreted  by  the  worker  her- 
self. She  rolls  the  whole  mass  between  her  forefeet  and  masticates 
it  with  her  mandibles,  until  a  small  gray  pellet  has  been  formed,  and 
with  this  she  flies  to  the  nest.  The  pellet  is  then  dropped  in  the 
proper  place  and  left  until  a  portion  of  it  adheres  to  the  edge  of  the 
cell  in  course  of  construction.  When  this  has  been  accomplished,  the 
insect  draws  the  pulp  from  a  ball  or  pellet,  into  a  long  thin  line,  to  the 
opposite  side  of  the  nest.  From  here  she  returns  to  the  starting  point 
and,  placing  her  tong-like  jaws  over  the  paper  thread,  closes  them 
and  simply  walks  slowly  backwards  away  from  the  point  of  contact, 
thus  flattening  it  out  into  a  long  gray  ribbon,  which  is  easily  shaped 
in  the  form  of  a  low  hexagonal  cell. 

In  this  manner  several  layers  of  paper  ribbon  are  applied,  each 
layer  above  the  other,  until  the  cell  is  of  proper  depth.  It  is  then 
ready  for  the  delicate  white  egg  which  the  queen  lays,  almost  at  its 
very  bottom.  The  egg  is  fastened  to  the  paper  wall  by  a  glutinous 
substance,  which  is  probably  the  same  secretion  that  is  used  in  making 
the  paper,  and  it  is  almost  impossible  to  remove  it,  without  leaving 
a  portion  of  its  tender  shell  adhering  to  the  inner  wall  of  the  cell. 

In  the  course  of  a  few  days  the  eggs  hatch  out  into  soft  footless 
maggots,  like  all  young  Hymenoptera,  and  it  is  at  this  period  of  their 
lives  that  they  are  subject  to  the  attacks  of  a  very  curious  beetle  para- 
site, known  as  the  Xenos.  The  young  of  this  insect  is  a  tiny  active 
creature  which  burrows  into  the  body  of  the  young  wasp.  There  it 
lives,  feeding  upon  the  body  of  its  host  during  its  hypermetamorpho- 
sis.  If  it  is  to  be  a  male,  it  transforms  into  a  chrysalis  and  soon  after 
this  hatches  out  from  the  body  of  the  wasp  to  live  its  short  adult  life, 
which  lasts  from  fifteen  minutes  to  three  days.  If  a  female,  however, 


98  INSECT  BEHAVIOR 

it  never  reaches  the  chrysalis  state,  but  when  the  maggot  host  itself 
changes  into  one,  the  apparently  immature  Xenos  pushes  one  end  of 
its  body  out  between  two  of  the  host's  abdominal  segments  and  there 
gives  birth  alive  to  a  great  many  tiny  beetles,  in  the  earliest  and  most 
undeveloped  stage  of  their  lives. 

Owing  to  the  position  of  the  comb,  when  the  young  wasp  emerges 
from  its  egg,  it  is  suspended  head  downwards  in  the  cell.  It  is,  how- 
ever, attached  to  the  cell  at  its  posterior  end  and  remains  so  until 
full  grown  and  ready  to  spin  its  cocoon.  At  this  period  it  becomes 
detached  but  the  bottom  of  the  silken  cocoon,  which  has  now  been 
spun,  forms  a  capstone  to  the  previously  open  cell  and  prevents  the 
youngster  from  tumbling  out.  In  this  position  the  young  wasp  trans- 
forms to  the  pupal  state,  in  which  it  remains  for  some  time  before 
issuing  as  a  perfect  insect  to  take  up  the  work  of  the  colony. 

After  this  event  the  cell  is  thoroughly  cleaned  out  by  the  workers 
and  used  over  again  by  the  queen.  The  entire  period  from  the  time 
that  the  egg  is  laid  until  the  full  grown  wasp  issues  from  its  cocoon, 
is  about  five  weeks;  thus  it  will  be  seen  that  the  same  cells  may  be 
used  several  times  during  a  single  season. 

The  last  brood  of  the  year  consists  mostly  of  queens  and  drones 
and  after  these  have  been  hatched  the  workers  of  the  colony  soon 
die.  The  inside  of  the  cells  may  then  be  found  to  contain  curious 
brownish  skins,  cast  off  by  the  chrysalids  and  which  the  workers  did 
not  have  time  to  remove  before  the  cold  weather  arrived. 

Unlike  the  large  globular  nests  of  the  hornets,  those  of  the  paper 
wasps  are  simply  a  mass  of  uncovered  cells,  ranging  in  numbers  from 
fifty  to  three  hundred.  These  are  suspended  by  a  single  central  stem 
from  the  undersides  of  large  overhanging  stones  or  from  beams  in 
old  barns  and  sheds. 

These  insects  are  undoubtedly  beneficial  from  the  fact  that  they 


•&     C 

4-        C 


THE  ORIGINAL  PAPER-MAKERS  99 

have  been  known  to  prey  upon  the  destructive  cabbage  caterpillar  l 
in  the  vicinity  of  Washington  and  also  in  Connecticut.  Howard,  in 
his  "Insect  Book,"  describes  their  actions  as  follows:  "The  wasps 
would  hover  above  a  plant  and  then  alight  and  walk  about  it,  but 
finding  nothing,  would  continue  to  the  next  plant,  and  so  on  to  the 
next.  In  the  sunny  center  part  of  the  field  the  cabbage  caterpillars 
were  exterminated,  but  in  the  shady  portions  next  to  a  patch  of  woods, 
they  wrere  present  in  great  numbers.  Wasps  do  not  see  small  objects 
clearly.  They  find  their  prey  more  by  sense  of  touch  than  by  sense 
of  sight,  and  as  they  prefer  the  sunshine  they  unconsciously  ignored 
the  abundant  caterpillars  in  the  shade." 

Kirby  has  left  us  the  following  extraordinary  account  of  the  manner 
in  which  the  workers  care  for  the  young  and  helpless  members  of  the 
community.  These  observations  apply  to  the  common  yellow  jacket 
or  hornet,  but  many  of  the  statements  hold  true  in  the  case  of  the 
paper  wasps,  although  I  have  not  as  yet  been  able  to  verify  them  all. 
"The  workers  are  the  most  numerous,  and  to  us  the  only  troublesome 
part  of  the  colony,  upon  whom  devolves  the  main  business  of  the  nest. 
In  the  summer  and  autumnal  months,  they  go  forth  by  myriads  into 
the  neighboring  country  to  collect  provisions;  and  on  their  return  to 
the  common  den,  after  reserving  a  sufficiency  for  the  nutriment  of  the 
young  brood,  they  divide  the  spoil  with  great  impartiality;  part 
being  given  to  the  females,  part  to  the  males  and  part  to  those  workers 
that  have  been  engaged  in  extending  and  fortifying  the  community. 
This  division  is  voluntarily  made,  without  the  slightest  symptom  of 
compulsion.  Several  wasps  assemble  around  each  of  the  returning 
workers,  and  receive  their  respective  portions.  It  is  curious  and  in- 
teresting to  observe  their  actions  upon  this  occasion.  As  soon  as  a 
wasp  that  has  been  filling  itself  with  the  juice  of  fruits,  arrives  at  the 
nest,  it  perches  upon  the  top,  and  upon  disgorging  a  drop  of  it's  sac- 

1  Pontius  rapae. 


ioo  INSECT  BEHAVIOR 

charine  fluid,  is  attended  sometimes  by  two  at  once,  who  share  the 
treasure.  The  first  drop  being  thus  distributed,  a  second  and  some-, 
times  a  third  is  produced,  which  falls  to  the  lot  of  the  others. 

"Wasps  do  not,  as  a  rule,  store  up  honey,  but  it  is  found  in  the  cells 
of  some  European  species  as  well  as  in  those  of  America. 

"Another  principal  enjoyment  of  the  workers  is  enlarging  and  re- 
pairing the  nest.  They  work  with  great  celerity;  and  though  a  large 
number  are  occupied  at  the  same  time,  there  is  not  the  slightest  con- 
fusion. Each  individual  has  its  portion  of  work  assigned  to  it,  ex- 
tending from  an  inch  to  an  inch  and  a  half,  and  is  furnished  with  a 
ball  of  ligneous  fiber,  scraped  by  its  powerful  jaws  from  posts,  rails 
and  the  like.  The  workers  also  clean  the  cells  and  prepare  them  to 
receive  another  egg,  after  the  first  has  passed  through  all  the  stages 
of  its  life  and  is  now  a  perfect  insect  working  with  the  rest." 

There  is  good  reason  for  thinking  that  wasps  have  sentinels  placed 
at  the  entrances  of  their  nests,  which,  if  you  can  seize  and  destroy, 
the  remainder  will  not  attack  you.  This  has  been  confirmed  by  the 
author.  If  a  nest  of  wasps  be  approached  without  alarming  the  in- 
habitants, and  all  communication  be  suddenly  cut  off  between  those 
out  of  the  nest,  and  those  within  it,  no  provocation  will  induce  the 
former  to  defend  it  for  themselves,  but  if  one  escapes  from  within, 
it  comes  with  a  very  different  temper  and  appears  commissioned  to 
avenge  public  wrongs.  In  fact,  very  few  incoming  bees  or  wasps 
will  attack  the  intruder.  Perhaps  it  is  because  the  insect  who  is  re- 
turning to  the  nest  sees  what  is  going  on  about  its  home,  while  the 
one  coming  from  inside  the  nest  is  confronted  suddenly  by  an  unusual 
form  when  it  reaches  its  usual  point  of  exit.  It  becomes  alarmed 
not  only  for  itself  but  for  the  safety  of  its  colony.  What  follows  is 
only  too  well  known  to  the  student  of  such  insects.  When  the.  workers 
make  their  rush  they  are  prepared  to  sacrifice  their  lives  in  the 
execution  of  their  orders. 


THE  ORIGINAL  PAPER-MAKERS  101 

The  first  cold  weather,  after  the  queens  have  entered  their  winter 
quarters,  produces  an  effect  upon  them  similar  to  that  which  is  pro- 
duced upon  the  woodchuck  and  other  animals  subject  to  torpor.  At 
first  a  partial  benumbment  takes  place,  but  the  insect,  if  touched,  is 
still  capable  of  moving  its  organs.  As  the  cold  increases,  all  the 
animal  functions  cease.  The  insect  breathes  no  longer  and  has  no  need 
of  a  supply  of  air;  its  nutritive  secretions  cease,  no  more  food  is  re- 
quired, and  it  has  all  the  external  symptoms  of  death. 

Thus  we  will  leave  the  few  survivors  of  a  once  great  insect  empire, 
perhaps  huddled  behind  the  picture  moulding  in  our  bed-room,  in- 
significant now  to  be  sure,  but  planning  perhaps  in  their  insect  heads, 
every  cell,  every  gallery,  and  every  passage  which  is  to  be  built  when 
the  new  colonies  are  founded  in  the  first  warm  days  of  April. 


CHAPTER  XIII 

INSECT  AND  OTHER  STRATEGISTS 

INSECTS,  like  all  other  creatures  of  this  earth,  from  sponges  to 
man,  must  partake  of  food,  for  without  it  there  would  be  no  life. 
It  is  a  simple  thing  to  say,  but  for  some  insects  of  the  lower 
orders,  to  procure  their  proper  nourishing  food  would  be  quite 
a  different  affair,  were  they  not  carefully  assisted  by  that  almost  in- 
tangible thing  called  instinct,  taught  in  the  school  of  nature.  To  be 
sure  there  are  many  of  the  higher  insects,  as  the  bees,  ants  and  wasps, 
who  are  fortunate  in  possessing  the  power  of  rapid  motion,  unfailing 
protection  and  well-developed  senses,  and  who  would  seldom  be 
hampered  in  the  quest  of  food,  but  how  would  the  lower  orders  of 
insects  fare,  were  it  not  for  the  marvelous  stratagems  that  nature  has 
taught  them?  Indeed,  they  would  not  fare  at  all,  for  if  they  were 
deprived  of  these  instinctive  strategic  methods  of  obtaining  their 
daily  sustenance,  such  insect  races  would  soon  become  a  thing  of  the 
past.  Should  events  of  this  nature  come  to  pass,  then  even  the  bal- 
ance of  nature  might  be  seriously  affected. 

Although  many  cases  might  be  shown  in  which  insects  and  their 
near  relatives  have  been  known  to  live  by  their  stratagems,  I  shall 
endeavor  only  to  describe  the  methods  employed  by  four  of  the  most 
interesting  groups. 

Through  the  long  summer  days  these  marvelous  things  are  fre- 
quently before  our  very  eyes,  yet  they  pass  unnoticed,  so  accustomed 
are  we  to  neglect  that  which  is  the  subject  of  daily  occurrence.  The 
webs  of  spiders  for  instance:  What  if  we  had  never  known  of  this 
marvel!  Would  it  seem  any  more  incredible  to  find  an  animal  spin- 

IO2 


Epeira  insularis 
An  orb-building  spider  laying  her  eggs.    They  are  afterwards  covered  in  a  sphere  of  silk.    Greatly  enlarged 


INSECT  AND  OTHER  STRATEGISTS  103 

ning  out  long  silken  threads;  weaving  these  threads  into  nets  more 
perfect  than  any  ever  made  by  human  hand  and  then  suspending  them 
with  the  best  judgment  where  the  wished-for  prey  is  most  abundant? 
Indeed  it  would  not  be  more  wonderful,  but  in  this  case,  as  in  so 
many  others,  we  neglect  the  actions  of  the  tiny  creatures,  which  in 
the  larger  ones  would  excite  our  admiration  and  endless  attention. 
In  fact,  the  minuteness  of  the  creature  renders  web-building  even 
more  wonderful  in  the  eyes  of  those  who  see  nature  as  she  really  is. 

The  spiders  might  well  be  termed  the  kings  of  strategists,  for  their 
beautiful  nets  of  glistening  silk  are  among  the  most  wonderful  of 
creations.  The  spiders  are  divided  into  many  groups,  but  the  orb- 
builders,  the  platform-builders  and  those  individuals  who  build  no 
webs  at  all  belong  to  the  most  interesting  families. 

The  first  group1  constructs  those  exquisite  geometrical  figures,  so 
wonderful  and  complicated  and  so  common  that  wre  seldom  stop  to 
realize  their  beauty.  They  hang  their  webs  in  window  corners,  door- 
ways, between  branches  of  trees  and  in  many  other  convenient  situa- 
tions where  their  prey  is  likely  to  be  abundant.  The  silken  threads 
which  compose  the  webs  of  the  orb-builders,  are  extremely  sticky, 
consequently  an  insect  seldom  gains  its  freedom  when  once  entangled 
in  these  death  traps. 

Many  of  the  orb-builders  sit  motionless  in  the  center  of  their  webs 
while  waiting  for  their  prey,  but  the  cunningest  of  them  hide  at  a  dis- 
tance within  a  tiny  bower  of  leaves,  which  are  carefully  shaped  and 
then  basted  together  with  soft  white  silk  by  the  spider.  From  the 
very  center  of  the  web,  the  creature  spins  two  long  delicate  threads 
which  run  into  the  opening  of  the  bower.  These  it  clasps  in  its  front 
feet  and  through  them,  the  slightest  motion  of  an  entangled  insect  is 
transmitted  to  the  hiding  cannibal. 

1  Epeiridae. 


104  INSECT   BEHAVIOR 

The  platform-building  group1  constructs  large  stages  of  silk  in  all 
sorts  of  situations,  but  they  are  particularly  fond  of  window-sills 
where  their  huge  webs  are  often  found.  At  one  end  of  the  stage  a 
large  silken  tube  is  constructed  in  which  the  owner  hides  and  from 
which  it  darts,  upon  seeing  an  insect  alight  upon  the  platform.  The 
silk  of  these  spiders  is  not  so  sticky  and  would  seldom  serve  to  entan- 
gle an  insect;  thus  it  will  be  seen  that  the  platform-builders  construct 
the  flat  white  stages  chiefly  to  attract  their  prey,  that  they  may  dart 
from  their  hiding  place,  seize  and  devour  it  at  leisure. 

The  third  and  fourth  groups2  embrace  some  of  our  largest  and  most 
powerful  harmless  spiders.  These,  however,  do  not  build  webs,  but 
simply  move  about  through  the  grass  in  fields  or  in  other  places  fre- 
quented by  their  favorite  insect  food.  In  fact,  they  literally  stalk 
their  game,  creeping  up  stealthily  and  then  springing  upon  it  from  a 
distance  of  several  inches. 

Occasionally  these  spiders  will  construct  a  flimsy  silken  tube  under 
a  stone,  but  the  majority  dig  deep  burrows  in  the  fields  which  they 
inhabit  and  their  big  hairy  heads  may  be  frequently  seen  squinting 
from  the  mouths  of  their  subterranean  homes. 

One  of  the  most  interesting  cases  of  insect  strategy  is  the  method  by 
which  the  oil  beetle3  succeeds  in  placing  its  young  within  the  nests 
of  bumble  bees,  upon  whom  they  are  parasitic  when  young.  The  oil 
beetle  is  well  named  from  the  fact  that  it  has  the  curious  ability  of 
discharging  a  noxious  oily  fluid  when  attacked  by  an  enemy. 

Towards  the  latter  part  of  summer  these  big  blue-bodied  insects 
may  be  seen  clumsily  walking  and  tumbling  among  the  early  fall 
flowers  which  the  bumble  bees  are  sure  to  visit  in  their  search  for 
nectar.  One  unfamiliar  with  these  two  insects  would  not  suspect  the 


1  Agalenidae. 

2  Drassidae  and  Lycosidse. 


Meloidae. 


I.    A  spider  which  used  an  empty  cicada's  shell  as  a  hiding  place  while  waiting  for  victims  to  enter  its  web 


An  example  of  spider  strategy.    The  web  of  this  spider,  Agalena  naevia,  was  watched  from  day  to  day  for  a 

period  of  two  months.    Ninety-eight  insects  were  taken  from  the  web,  carefully  dried  and  ground  up,  making 

in  all,  the  pile  upon  which  the  spider  rests.    Only  the  day  catches  were  removed  from  the  web.    The  list  of 

insects  caught  would  include  moths,  butterflies,  bees,  wasps,  flies,  bugs,  grasshoppers  and  numerous 

other  orders.    As  an  example  of  successful  strategy  in  the  capture  of  food  it  is  unique 


INSECT  AND  OTHER  STRATEGISTS  105 

close  relation  which  exists  between  their  simultaneous  reappearances, 
for  the  oil  beetle  is  out  on  business  which,  unhappily  enough,  will 
prove  detrimental  to  the  welfare  of  the  bee's  future  household.  The 
beetle's  reason  for  climbing  among  the  flowers  is  to  lay  her  eggs  upon 
their  blossoms;  an  intruder  to  be  sure  upon  the  property  which  in  all 
nature  seems  justly  and  only  that  of  the  hard-working  bees.  In  the 
course  of  a  few  days  the  beetle's  eggs  hatch  out  into  tiny  six-legged 
creatures,  utterly  unlike  their  parents.  Later  when  the  Bumble  bee 
comes  to  gather  her  store  of  honey,  these  active  little  insects  jump 
upon  her  back  and,  clinging  fast  to  her  hair,  are  carried  to  the  nest, 
where  first  they  eat  the  bee's  own  eggs  and  later  the  food  which  she 
has  stored  up  for  her  young. 

Another  instance  of  the  stratagems  of  insects  in  procuring  their 
prey  is  that  of  a  remarkable  insect  called  the  ant  lion.1  It  is  widely 
separated  from  the  race  of  insects  which  includes  the  oil  beetles,  but  it 
is  perhaps  the  most  interesting  of  all  preying  insect  creatures.  It  is,  in 
reality,  the  young  of  a  certain  nerve-winged  insect,  somewhat  resem- 
bling a  dragon  fly.  It  is  about  an  inch  in  length,  and  the  outline  of  its 
body  is  more  or  less  triangular,  the  widest  point  being  at  the  tail  end. 
It  has  six  powerful  legs  and  the  mouth  is  supplied  with  two  incurved 
jaws  which  give  the  insect  a  frightful  appearance.  Its  sole  food  con- 
sists of  the  juices  of  other  insects,  particularly  ants,  but  on  seeing  the 
lion  for  the  first  time,  it  hardly  seems  possible  that  it  could  ever  secure 
a  single  meal.  Its  pace  is  slow  and  tedious,  but  worst  of  all  it  can 
walk  in  no  other  direction  than  backwards!  What  chance  would  it 
have  with  a  nervous,  fast-moving  ant?  It  could  not  give  chase,  and 
to  stay  motionless  would  be  equally  ridiculous,  for  its  grim  appear- 
ance would  be  sufficient  to  impress  upon  all  insect  wanderers,  the 
prudence  of  keeping  at  a  respectful  distance!  The  ant  lion's  appetite 

1  Myrmeleonidae. 


io6  INSECT   BEHAVIOR 

is  tremendous  and  it  will  seldom  partake  of  food  unless  it  has  first  had 
the  joy  of  killing  it. 

Here  again  the  insect  accomplishes  by  artifice  what  its  ordinary 
unaided  efforts  would  have  been  unequal  to.  It  digs  in  dry  loose 
sand  a  conical  pit  in  the  bottom  of  which  it  lies  concealed,  and  there 
seizes  those  unfortunate  ants  which,  chancing  to  stumble  over  the 
edge,  are  precipitated  down  the  sloping  sides  into  the  lion's  waiting 
jaws.  Sometimes  the  ant  is  able  to  stop  half  way  down,  regain  its  foot- 
ing and  scramble  madly  for  the  top.  No  sooner  does  the  ant  lion  per- 
ceive this  than,  shaking  off  its  inactivity,  it  ludicrously  shovels  sand 
upon  its  head  with  its  front  feet  and  hurls  it  vigorously  upon  the  body 
of  the  escaping  ant.  This  heavy  shower  from  below  invariably  starts 
the  sides  of  the  pit  to  slide  under  the  unfortunate  insect's  feet  and  at 
length  it  is  carried  down  to  the  greedy  devourer  in  the  bottom  of 
the  pit. 

The  methods  employed  by  the  ant  lion  in  building  its  pitfall  are 
extremely  interesting  and  I  must  not  fail  to  mention  the  fact  that  we 
have  a  species  of  this  remarkable  insect  occurring  quite  commonly  in 
the  United  States.  Many  accounts  have  been  written  of  their  curious 
habits,  both  in  this  country  and  in  Europe.  The  following  is  an 
extract  from  a  paper  written  many  years  ago  by  Reaum,  and  is  an 
admirable  description  of  an  ant  lion's  energy  in  constructing  its  pit: 

"Its  first  concern  is  to  find  a  soil  of  loose  dry  sand,  in  the  neighbor- 
hood of  which,  indeed,  its  provident  mother  has  previously  taken  care 
to  place  it,  and  in  a  sheltered  spot  near  an  old  wall,  or  at  the  foot  of  a 
tree.  This  is  necessary  on  two  accounts:  The  prey  most  acceptable 
to  it  abounds  there,  and  no  other  soil  would  suit  for  the  construction 
of  its  snare.  Its  next  step  is  to  trace  in  the  sand  a  circle,  which,  like 
the  furrow  with  which  Romulus  marked  out  the  limits  of  his  new 
city,  is  to  determine  the  extent  of  its  future  abode.  This  being  done, 
it  proceeds  to  excavate  the  cavity  by  throwing  out  the  sand  in  a  mode 


The  fishing  net  of  a  hydropsychid 
The  maker  of  the  snare  is  shown  at  the  right.    These  creatures  swarm  in  brooks.    Greatly  enlarged 


INSECT  AND  OTHER  STRATEGISTS  107 

not  less  singular  than  effective.  Placing  itself  in  the  inside  of  the 
circle  which  it  has  traced,  it  thrusts  the  hindpart  of  its  body  under  the 
sand  and  with  one  of  its  forelegs  serving  as  a  shovel,  it  charges  its  flat 
and  square  head  with  a  load,  \vhich  it  immediately  throws  over  the 
outside  of  the  circle  with  a  jerk  strong  enough  to  carry  it  to  the  dis- 
tance of  several  inches.  This  little  manoeuvre  is  executed  with  sur- 
prising promptitude  and  address.  A  gardener  does  not  operate  so 
quickly  or  so  well  with  his  spade  and  his  foot,  as  the  ant  lion  with  its 
head  and  leg.  Walking  backwards  and  constantly  repeating  the  proc- 
ess, it  soon  arrives  at  the  part  of  the  circle  from  which  it  set  out.  It 
then  traces  a  new  one,  excavates  another  furrow  in  a  similar  manner, 
and  by  a  repetition  of  these  operations,  at  length  arrives  at  the  center 
of  its  cavity.  One  circumstance  deserves  remark — that  it  never  loads 
its  head  with  the  sand  lying  on  the  outside  of  the  circle,  though  it 
would  be  as  easy  to  do  this  with  the  outer  leg,  as  to  remove  the  sand 
within  the  circle  by  the  inner  leg.  But  it  knows  that  it  is  the  sand  in 
the  interior  of  the  circle  only  that  is  to  be  excavated,  and  it  therefore 
constantly  uses  the  leg  next  to  the  center.  It  will  readily  occur,  how- 
ever, that  to  use  one  leg  as  a  shovel  exclusively  throughout  the  whole 
of  such  a  toilsome  operation,  would  be  extremely  wearisome  and  pain- 
ful. For  this  difficulty  our  ingenious  pioneer  has  a  resource.  After 
finishing  the  excavation  of  one  circular  furrow,  it  traces  the  next  in  an 
opposite  direction;  and  thus  alternately  exercises  each  of  its  legs 
without  tiring  either!" 

There  is  one  other  insect,  a  Caddice  worm,1  well  worthy  of  a  place 
among  these  instinctive  strategists.  This  creature  lives  under  the 
water.  It  is  a  true  fisherman  in  every  sense  of  the  word,  for  it  catches 
its  food  by  constructing  a  silken  net  in  the  current  of  the  stream  which 
it  inhabits.  The  mesh  of  this  net  is  almost  perfect  in  its  symmetry, 
each  strand  of  silk  being  fastened  at  a  right  angle  with  the  one  next 

1  Hydropsychidae. 


io8  INSECT  BEHAVIOR 

to  it.  They  are  funnel-shaped  affairs  and  the  insect  is  cunning 
enough  to  always  place  it  so  that  the  running  water  enters  through  the 
largest  end,  thus  keeping  the  net  tight  and  in  one  position.  The  insect 
spends  the  majority  of  its  time  under  stones  or  pieces  of  old  water- 
logged wood,  visiting  its  net  when  in  need  of  food,  and  finally  leaves, 
the  water  after  many  months,  in  the  form  of  a  filmy-winged  insect 
known  as  a  Caddice  fly. 

How  marvelous  it  all  is,  that  nature  has  supplied  each  and  every 
one  of  her  creatures,  not  only  with  a  method  of  finding  their  proper 
food,  but,  as  in  the  cases  which  I  have  just  described,  she  has  shown 
them  how,  by  artifice,  they  may  capture  with  ease  and  no  loss  of 
energy,  their  desired  articles  of  diet. 


Ants  surrounding  and  pillaging  a  larger  one  bearing  a  pupa.    Twice  life  size 


Brown  ants  transporting  aphids  to  their  underground  nest 

One  ant  may  be  seen  gently  lowering  an  aphid  to  a  waiting  porter  whose  head  protrudes  from  the  ground. 

third  ant  looks  on  from  above.    Enlarged  twice 


_2      O 

s< 


--  i 

.  '  — 

-E  -= 

.-:  = 

U.  O 


—     r: 

~=     = 


CHAPTER  XIV 

OBSERVATIONS  ON  ANTS 

AS  far  back  as  one  may  search  through  the  entomological 
literature  of  the  past,  there  will  be  found  records  of  ant 
behavior.  Ever  since  man  has  been  civilized  to  the  degree 
of  recording  events,  he  has  realized  how  wonderful  is  the 
highly  organized  social  life  of  these  insects. 

So  much  has  been  said  in  fact,  regarding  their  actions,  that  it  has 
become  difficult  indeed  to  record  anything  new,  and  all  but  impossi- 
ble to  relate  any  of  their  known  activities  in  a  new  enough  manner 
to  be  entertaining. 

It  is  strange,  however,  that  no  one  has  attempted  to  bring  us  face  to 
face  with  ants  in  their  daily  life,  in  such  a  way  that  it  is  unnecessary 
to  depend  upon  the  imagination  for  the  actual  picture.  Poets  and 
artists  have  sketched  them  and  sung  their  praises,  scientists  have  gone 
minutely  into  the  significance  of  their  behavior,  yet  who  has  honestly 
given  the  camera  its  chance? 

With  this  idea  in  view  I  have  gathered  together  the  material  for 
this  chapter.  However  meagre  the  results,  they  have  been  dearly 
bought  by  many  failures  and  experiences  that  can  be  only  realized  by 
one  who  has  worked  in  the  field  of  insect  photography. 

Let  us  wander  out  for  a  time  into  the  lowly  world  of  ants,  down 
among  the  grass  and  earth,  or  perhaps  in  the  heart  of  some  aged  and 
broken  tree  of  other  days.    Let  us  live  among  these  creatures  them- 
selves, watch  their  activities  and  perhaps  discover  something  new. 
There,  at  the  base  of  the  old  maple,  where  its  trunk  enters  the 

ground,  is  a  tiny  pile  of  wooden  pellets.    Some  five  feet  above,  a  car- 

109 


i  io  INSECT   BEHAVIOR 

penter  ant *  thrusts  her  head  from  a  crack  in  the  ancient  bark.  In 
her  jaws  is  a  bit  of  wood  debris  from  the  work  of  enlarging  the  nest 
within,  where  other  individuals  of  her  kind  are  cutting  away  the  fiber 
with  their  powerful  jaws. 

The  ant  that  we  are  watching  is  only  a  cog  in  the  great  machine 
that  makes  up  the  colony  and  her  part  of  the  work  is  simply  gathering 
these  wood  chips  and  carrying  them  to  the  outside  of  the  tree.  Here 
she  either  drops  or  transfers  them  to  other  porters  who  carry  them 
some  distance  away  from  the  spot  where  the  nest  is  being  constructed. 

Several  porters  are  also  assigned  to  the  task  of  removing  the  pellets 
which  are  dropped  at  the  base  of  the  tree,  and  if  we  were  to  watch 
long  enough,  the  pile  which  first  attracted  our  attention  would  grad- 
ually be  removed  until  no  evidence  of  activities  within  the  tree 
remained. 

The  work  of  enlarging  the  home  may  be  carried  on  by  ten  individ- 
uals or  a  thousand,  without  affecting  the  regular  routine  of  the  ant 
city.  As  we  watch  the  crack  in  the  bark  for  the  head  of  the  porter 
with  her  endless  wood  pellets,  other  ants  are  seen  hurrying  in  and  out, 
ants  of  several  sizes,  bearing  a  variety  of  burdens.  Occasionally  one 
stops  to  give  the  characteristic  greeting  by  crossing  or  touching  feelers 
with  a  fellow  worker,  a  sort  of  "Same  Lodge,"  as  it  were,  but  the 
general  appearance  about  the  entrance  is  one  of  haste,  and  reminds  me 
of  the  Grand  Central  Station  a  minute  or  so  before  the  departure  of  a 
popular  commuters'  train. 

Here  is  an  ant  bearing  a  tiny  whitish  grub-like  object,  dead  but 
good  eating  nevertheless  for  the  hungry  ones  within.  Closely  follow- 
ing upon  her  footsteps  is  a  big  powerful  member  of  the  colony  strug- 
gling towards  the  entrance  in  the  bark,  with  the  entire  springing  leg 
of  a  grasshopper.  It  weighs  as  much  or  more  than  the  ant  herself  and 
the  spines  upon  it  must  have  caused  her  no  end  of  trouble,  yet  she  has 

1  Camponotus  pennsylvanicus. 


South  American  leaf-cutter  ants,  paralyzed  and  dying  after  being  attacked  by  a  smaller  species.    Note  the  por- 
tions of  leaves  which  the  victims  were  carrying  when  attacked.    Much  enlarged 


A  group  of  ants,  all  linked  together,  but  dead  and  motionless  when  the  picture  was  taken.    Greatly  enlarged 


OBSERVATIONS   ON   ANTS  in 

struggled  on  (who  knows  from  where?)  with  that  bit  of  food,  faithful 
to  her  queen  and  colony. 

Into  the  darkness  of  the  nest  she  plunges,  now  assisted  by  another 
worker.  She  disappears  through  tunnels  and  alleyways  and  finally 
lands  her  dainty  morsel  in  some  store  room  far  in  the  depth  of  the  tree. 
All  this  she  has  done  in  utter  darkness  and  it  is  strange  that  she  should 
be  able  to  work,  unaffected,  either  by  glaring  sunlight,  which  she  has 
just  left,  or  the  blackness  of  the  nest. 

Now  let  us  look  within  the  nesting  tree  and  see  the  multitude  of 
insect  life  that  inhabits  its  endless  tunnels  and  galleries.  A  complete 
colony  contains  one  or  two  fertile  queens,  whose  sole  duty  is  the 
laying  of  eggs  and  without  whose  influence,  the  lesser  personages  of 
the  tribe  would  soon  lose  their  instincts  and  die.  Besides  these  regal 
insects  there  are  a  multitude  of  creatures  known  as  "Workers,"  unde- 
veloped females  in  reality,  upon  whose  shoulders  the  main  labor  of 
the  community  rests.  Then  there  are  the  young  males,  and  females, 
the  weaker  sex,  to  become  royal  mothers  after  they  have  left  the  old 
home  in  what  is  known  as  the  "Marriage  Flight"  with  the  young 
males. 

New  colonies  are  started  in  this  way  by  the  younger  generation, 
who  at  maturity  are  actually  driven  from  home  by  the  workers.  The 
young  males,  however,  never  enter  the  new  nest.  Weak  and  unable 
to  provide  for  themselves,  they  soon  die  of  starvation  or  fall  easy  prey 
to  their  many  enemies.  Thus  does  Nature  dispense  with  these  useless 
members  when  the  "Marriage  Flight"  is  ended. 

The  young  queens  are  independent,  strong  and  well  equipped  to 
take  care  of  themselves,  as  indeed  they  must  be,  for  each  must  lay  the 
foundations  of  a  new  colony.  Their  first  action  is  to  rid  themselves 
of  their  no  longer  useful  wings,  which  they  do  with  enthusiasm,  sever- 
ing them  close  to  the  body  with  their  own  jaws!  When  this  has  been 
accomplished  the  fertile  insect  crawls  into  some  tiny  crack  or  cavity 


ii2  INSECT   BEHAVIOR 

and  lays  her  first  eggs.  This  first  brood  of  antlings  must  be  fed  and 
tended  by  the  queen  herself,  until  upon  reaching  maturity  they  are 
able  to  take  up  the  labor  for  their  sovereign.  Brood  after  brood  are 
hatched  and  reared  and  as  each  ant  becomes  a  finished  product  she 
assumes  her  part  of  the  responsibility.  Thus,  by  the  end  of  a  season, 
the  young  queen  becomes  indeed  a  royal  mother  of  a  loyal  army  of 
supporters,  workers  and  soldiers. 

Interesting  and  wonderful  are  the  ants  known  as  the  slave  makers,1 
species  that  actually  organize  raids  upon  the  nests  of  ants  of  another 
species  for  the  purpose  of  stealing  their  eggs  and  kidnapping  their 
young.  At  the  start  of  such  a  raid,  some  little  resistance  is  usually 
offered  by  the  tribe  that  has  been  attacked,  but  owing  to  the  sudden 
and  unexpected  nature  of  these  bombardments,  the  slave  makers  are 
often  successful.  They  are  fearless  and  strong  and  quite  willing  to 
die,  if  need  be,  in  attempting  to  secure  an  egg  or  antling  from  the 
pillaged  nest. 

Sometimes  the  defending  insects  will  form  a  circle  about  the  nest, 
which  serves  to  keep  the  enemy  off,  until  other  members  of  the  colony 
have  had  time  to  snatch  up  eggs  and  young  and  make  for  safety  by 
some  back  door  or  passageway.  But  ants  that  have  nearly  made  good 
their  escape  are  often  chased,  cornered  and  robbed  of  their  precious 
burdens  by  the  alert  and  watchful  slave  makers. 

When  the  raid  has  been  brought  to  a  successful  end,  the  attacking 
party  returns  with  its  booty  to  the  home  nest  where  it  is  welcomed, 
perhaps  cheered  by  the  non-combatant  members  of  the  colony. 

The  supply  of  stolen  eggs  and  young  are  now  raised  to  maturity, 
after  which  in  the  case  of  one  species,  they  become  subjected  to  abso- 
lute slavery.  The  reflex  of  this  habit  upon  the  Slave  Makers  is  just 
what  one  would  expect;  deterioration.  The  entire  work  of  a  nest  is 
often  put  upon  the  shoulders  of  the  slaves  and  in  some  cases,  the  war- 

1  Formica  sanguinea  and  Polyergus  rufescens,  both  slave-making  species. 


Carpenter  Ants  proceeding  to  battle.     Dead  specimens.     Slightly  enlarged. 
Warrior  Carpenter  Ant  with  severed  head  of  an  enemy  still  clinging  to  it.    Greatly  enlarged. 
A  train  of  Army  Ants.    At  least  five  hundred  thousand  individuals  in  the  train. 
Leaf  Cutter  Ants  of  South  America  showing  heads  and  abdomens  eaten  out  by  a  smaller 
species  of  ant.    Three  times  life  size. 


OBSERVATIONS   ON   ANTS  113 

riors  of  a  colony  will  not  even  feed  themselves,  but  depend  upon  the 
slaves  to  keep  them  from  starving. 

There  is  another  species  of  slave  makers,  whose  case  is  quite  at 
variance  with  the  insect  mentioned  above.  This  ant  expends  as  much 
energy  in  home  building  and  other  work  as  it  does  in  kidnapping. 
Consequently  its  home  is  in  a  healthier  condition  than  that  of  its 
dependent,  indolent  cousin,  even  though  its  architecture  is  a  cross 
between  the  ideas  of  slave  and  master. 

But  time  will  undoubtedly  develop  this  ant  into  becoming  more 
and  more  indolent,  as  it  becomes  more  accustomed  to  depending  upon 
its  slaves.  Indolence  means  the  breaking  down  of  its  once  strong 
home  and  instincts.  Time  may  even  obliterate  it. 

Let  us  leave  these  creatures  already  on  the  downward  path  to  their 
fate.  There  are  other  ants  to  be  considered,  insects  that  have  learned 
to  better  themselves. 

There  is  a  tiny  family  of  true  bugs,  known  as  Aphids,  often  bright 
red  or  green  in  color,  which  gather  in  great  clusters  upon  the  stems 
and  leaves  of  plants.  They  are  equipped  with  a  sharp  sucking 
apparatus  with  which  to  draw  the  sweet  sap  from  the  plants  upon 
which  they  live.  Strange  as  it  may  seem,  many  kinds  of  ants  have 
learned  to  extract  the  sweet  liquid  from  the  bodies  of  these  little 
insects  without  injuring  them  in  any  way.  This  operation  is  per- 
formed by  stroking  the  aphid  very  gently  with  the  feelers  and  jaws. 
A  stimulus  is  set  up  by  the  stroking,  whereby  the  aphid  exudes  a 
minute  drop  of  honey  dew,  which  is  greatly  relished  by  the  ant.  So 
much  have  ants  become  associated  with  aphids  that  they  are  generally 
known  as  ants'  cows,  and  wherever  the  little  creatures  are  found 
clustered  upon  a  plant,  one  is  almost  sure  to  see  the  attending  ants 
fussing  about  and  tenderly  protecting  them. 

Under  normal  conditions,  most  of  the  aphids  die  as  cold  weather 
approaches,  and  this  the  ants  appear  to  be  aware  of.  With  them  they 


ii4  INSECT   BEHAVIOR 

perform  one  of  their  most  interesting  habits.  The  first  frosty  wind 
that  suggests  the  coming  of  winter,  sends  the  ants  scurrying  to  their 
respective  herds.  The  tiny  cattle  are  tenderly  gathered  up  and  born 
away  uninjured  to  the  ants'  subterranean  nests.  Here  they  are  placed 
upon  exposed  roots  below  the  frost  line,  that  the  ant  colony  may  enjoy 
a  fresh  supply  of  honey  throughout  the  winter,  when  for  the  most 
part,  the  insect  world  is  cold  and  dead. 

Even  more  wonderful  is  the  fact  that  ants  have  been  observed  to 
gather  the  eggs  of  aphids  in  the  fall,  carry  them  into  their  nests  for  the 
winter  and  in  the  following  spring,  place  the  young  cattle  which 
emerge  from  them  upon  their  natural  food  plants.  Here  they  were 
allowed  to  remain  during  the  summer  in  exchange  for  the  honey-sap 
which  they  extracted  from  the  plants. 

Among  such  masses  of  insects  as  people  the  ant  world,  one  naturally 
finds  a  series  of  happenings,  quite  similar  to  the  events  in  the  world 
as  we  know  it.  Where  great  numbers  of  creatures  are  found  living 
together,  no  matter  what  they  are,  or  how  low  they  may  be  in  the  scale 
of  life,  there  are  sure  to  be  disagreements  between  certain  members 
of  the  race.  How  these  troubles  originate  is  not  for  me  to  say,  but  it 
is  true  in  the  ant  world,  as  in  ours,  that  great  upheavals  often  occur, 
usually  between  colonies  of  the  same  species.  Starting  perhaps 
between  two  or  three  individuals,  these  disagreements  often  end  in 
general  warfare  between  the  two  factions. 

These  ant  struggles  are  true  wars,  where  only  death  can  decide  the 
issue,  for  they  fight  hand  to  hand,  or  better,  jaw  to  jaw,  until  one  has 
destroyed  the  other.  The  battle  is  composed  of  hundreds  of  warriors, 
each  fighting  loyally  and  frantically  until  its  last  spark  of  life  is 
extinguished. 

Few  people  have  been  fortunate  enough  to  witness  one  of  these 
wars,  yet  by  a  strange  turn  of  fate,  the  author  came  abruptly  upon  the 
tail  end  of  a  furious  battle  which  had  probably  been  going  on  during 


Young  brown  ants  tenderly  cared  for  by  their  nurses.    Twice  life  size 


Young  brown  ants  brought  up  beneath  a  sun-warmed  stone.    Twice  life  size 


OBSERVATIONS   ON   ANTS  115 

most  of  the  previous  night.  This  fight  took  place  between  two 
colonies  of  carpenter  ants,1  in  the  eaves  of  an  outbuilding  and  work- 
shop. When  the  doors  of  the  shop  were  opened  in  the  morning  great 
numbers  of  black,  mangled  bodies  were  seen  upon  the  floor,  covering 
an  area  nearly  six  feet  in  diameter.  The  creatures  had  been  battling 
in  the  eaves  above  the  door,  and  in  the  fury  of  the  struggle  had 
dropped  to  the  floor  below. 

There  were  legs  and  feelers,  several  heads  and  broken  bodies  lying 
about  in  profusion,  and  here  and  there  were  little  groups  of  ants,  all 
dead,  but  still  linked  together  in  a  death  grip.  Other  mangled  bodies 
still  writhed  in  agony.  There  was  one  huge  warrior  with  the  severed 
head  of  an  enemy  still  clinging  to  its  feeler,  and  a  few  couples  were 
still  fighting  furiously  upon  the  floor. 

One  could  hear  a  distinct  clicking  and  snapping  as  the  powerful 
knife-like  jaws  opened  and  closed  upon  the  unfortunate  victims.  I 
even  saw  one  little  ant  with  every  limb  gone  and  its  feelers  both  cut 
off,  still  bravely  fighting  upon  its  back,  with  a  much  larger  and  quite 
unharmed  antagonist.  Above,  in  the  eaves,  small  groups  of  warriors 
looked  down  upon  the  aftermath,  as  though  staring  with  satisfaction 
upon  the  scene  of  carnage  which  they  had  left. 

It  brought  home  to  me,  as  no  insect  event  has  ever  done  before,  how 
like  us  these  creatures  are!  One  offends,  and  the  whole  innocent  race 
suffers,  some  only  slightly  to  be  sure,  but  others  pay  with  their  life 
and  blood  for  the  wrong  of  another! 

The  leaf-cutting  ants 2  of  tropical  America  during  their  foraging 
excursions  are  frequently  attacked  by  a  smaller  species  of  ant  that 
easily  conquer  them,  thereafter  eating  out  the  abdomen  and  head  of 
their  captives.  This  pugnacious  ant  is  a  tiny  creature,  measuring 

1  Camponotus  pennsylvanicus. 

2  These  insects  belong  to  the  genus  atta.     They  grow  a  fungus,  Rozites  gongylo- 
phosa,  upon  fragments  of  leaves,  which  serves  as  food  for  the  colony. 


n6  INSECT   BEHAVIOR 

three  millimeters  in  length,  and  it  is  remarkable  that  they  are  so  easily 
able  to  vanquish  the  large  and  powerful  leaf-cutters  that  measure 
eight  millimeters  in  length  and  possess  long  legs  and  powerful 
mandibles. 

The  method  of  attack  is  interesting.  Grasping  their  large  oppo- 
nents by  the  middle  of  the  tarsi,  the  minute  warriors  bend  their  bodies 
inward,  and  with  head  lowered  hang  on  with  great  strength  and 
force.  Two  or  more  attack  the  leaf-cutter  at  once  and  apparently  put 
it  into  such  a  state  of  panic  that  no  resistance  is  offered.  It  is 
probable  that  the  leaf-cutters  could  easily  rid  themselves  of  these  pests 
were  it  not  for  the  fact  that  they  are  first  beaten  by  their  own  fright. 

Observation  of  this  strange  state  of  affairs,  existing  between  these 
two  species  of  ants,  led  to  the  following  experiments,  which  I  believe 
are  worthy  of  recording.  For  the  purpose  of  experiment,  two  vials 
of  liquid  were  produced  by  grinding  some  of  the  dead  leaf-cutters  in 
a  mortar,  to  which  a  few  drops  of  boiled  water  were  added.  This 
was  let  stand  for  several  hours  before  being  strained  for  use. 

For  the  first  experiment  a  drop  of  solution,  produced  from  the 
heads  and  bodies  of  the  leaf-cutters,  was  injected  into  the  body  of  a 
vigorous  wasp,  a  creature  many  times  larger  and  stronger  than  an  ant. 
The  insect  immediately  showed  signs  of  stupor,  twitched  heavily  and 
rubbed  its  forelegs  over  its  head  continually  for  several  minutes,  then 
recovered  and  flew  to  the  window  pane.  A  second  injection  of  the 
same  fluid,  and  a  very  heavy  one,  produced  the  same  result,  followed 
by  recovery  and  the  insect  walking  away  when  liberated!  There  is 
evidently  no  poison  then,  in  the  heads  or  bodies  of  the  leaf-cutters, 
which,  it  will  be  remembered,  are  the  only  parts  eaten  by  the  smaller 
ants. 

As  a  second  experiment,  a  drop  of  liquid  made  from  the  thorax  of 
the  leaf-cutter  was  injected  into  a  fresh  wasp.  This  resulted  in  the 
insect's  being  completely  overcome  for  perhaps  half  a  minute,  fol- 


OBSERVATIONS  ON  ANTS  117 

lowed  by  part  recovery,  then  a  second  spell  of  weakness,  more  severe 
than  the  first,  violent  twitching,  then  rolling  upon  the  back.  A 
second  injection  of  the  same  fluid  resulted  in  death  within  half  a 
minute. 

From  the  above  it  is  plain  why  the  attacking  ants  leave  the  thorax 
of  the  leaf-cutters  untouched,  as  it  contains  material  highly  poisonous 
to  the  smaller  insects. 

Continuing  the  work  of  experiment,  a  solution  was  produced 
from  the  entire  bodies  of  the  smaller  ants.  A  drop  of  this  fluid 
administered  to  a  wasp  between  the  second  and  third  pairs  of  legs 
produced  immediate  paralysis  of  these  organs.  Another  injection 
given  just  in  front  of  the  forelegs  produced  the  same  result  in  that 
pair.  Now,  if  the  small  ants  are  closely  watched  during  their  attacks 
upon  the  leaf-cutters,  they  will  be  seen  to  attach  themselves  first  to  the 
unfortunate  insect's  legs.  Here  they  cling  for  a  few  seconds  before 
gradually  working  their  way  towards  the  head  of  their  prey. 

At  length  they  arrive  at  this  point  and  remain  doggedly  clinging  to 
the  mandibles  or  mouth  parts  of  the  larger  ant.  From  what  we  have 
observed  the  following  is  a  possible  explanation  of  what  takes  place: 

The  third  experiment  has  shown  that  whatever  part  is  injected  with 
the  small  ant's  poison,  becomes  subject  to  paralysis  in  a  very  short 
time.  The  smaller  ant  attacks  the  head  of  the  leaf-cutter  and  the 
latter,  as  we  have  observed,  makes  no  effort  to  use  its  mandibles  upon 
its  tiny  persecutor.  The  smaller  ant's  course  is  plain.  It  attacks  the 
leaf-cutter's  head;  paralysis  of  the  muscles  governing  the  mandibles 
and  biting  parts  results  and  the  larger  insect  can  do  nothing  to  protect 
itself  against  a  number  of  the  smaller  ones,  who  soon  drag  it  to  their 
lair! 

Before  closing  this  chapter  on  various  phases  of  ant  behavior,  that 
I  have  been  able  to  record  from  time  to  time,  it  is  fitting  that  I  set 


u8  INSECT  BEHAVIOR 

down  a  few  notes  on  the  strange  army  ants  of  South  America.1 

These  insects  roam  the  dimly  lighted  jungles  in  vast  armies,  travel- 
ing about  from  day  to  day  like  bands  of  gypsies.  As  they  progress, 
carrying  eggs  and  young  with  them,  they  hunt  out  and  capture  all 
insect  life  that  chances  in  their  path.  The  booty  is  torn  to  pieces  and 
then  borne  to  their  nest,  where  the  queen  and  nurses,  with  the  tribe's 
precious  eggs  and  young,  together  with  a  number  of  guards,  remain  in 
safety  until  the  return  of  the  warriors.  Scouts  are  doubtless  sent 
ahead  from  day  to  day,  whose  duty  it  is  to  find  a  safe  shelter  for  the 
main  army,  which  follows  shortly  afterwards. 

At  six  o'clock  one  morning  my  attention  was  attracted  by  a  long  thin 
line  of  army  ants  moving  hurriedly  across  the  compound.  Tracing 
their  line  of  march  I  soon  found  them  to  be  moving  in  a  zigzag  course 
to  a  hole  underneath  some  blocks  of  concrete  that  had  originally 
served  as  foundations.  Evidently  they  had  been  moving  for  several 
hours,  perhaps  during  the  night,  for  a  distinct  path  two  inches  or 
more  in  width  had  been  trodden  smooth  by  them. 

Here  and  there  a  leaf  or  twig  hindered  their  progress  and  at  other 
places  a  depression  in  the  ground  called  for  the  unnecessary  expendi- 
ture of  energy.  To  overcome  these  difficulties,  a  wonderful  sense  of 
duty  was  displayed  by  certain  members  of  the  tribe,  who  formed  solid 
living  bridges,  over  which  the  others  passed.  Sometimes  but  a  few 
were  necessary  to  bridge  the  obstacle,  but  in  other  places,  dozens  and 
dozens  of  individuals  linked  themselves  together  to  form  the  bridge 
and  complete  the  road  as  a  smooth,  comfortable  highway  for  their 
tribe. 

The  ants  traveled  from  five  to  eight  abreast,  never  in  a  wider 
column,  and  the  moving  army  reached  from  the  concrete  blocks  clear 
across  the  compound  and  thence  out  of  sight  into  the  underbrush,  a 

1  These  observations  were  made  in  the  jungle  near  Bartica,  British  Guiana,  in 
May,  1916. 


A  snowy  tree  cricket  singing 

These  insects  produce  their  song  by  rasping  their  delicate  wings  together  which  causes  them  to  vibrate  and  pro- 
duce the  sound 


OBSERVATIONS  ON  ANTS  119 

distance  of  at  least  three  hundred  feet.  This  is  not  unusual.  They 
move  thus  for  hours  at  a  time  and  their  numbers  are  enormous.  I 
estimate  that  this  particular  army  contained  at  least  half  a  million 
individuals. 

The  Army  ant  remains  in  no  regular  home.  They  are  a  crowd  of 
gypsies,  that  travel  throughout  their  lives,  living  upon  the  land  and 
carrying  their  possessions  with  them.  In  the  line  of  march,  one 
sees  thousands  of  nurses  carrying  eggs,  larvae  and  pupae.  They  are 
usually  in  the  center  of  the  column,  guarded  on  either  side  by  workers 
of  various  sizes  and  soldiers  with  tremendous  heads  and  mandibles, 
shaped  like  elephant  tusks  and  gleaming  like  ivory.  Now  and  again 
a  lieutenant  rushes  back  along  the  line,  sometimes  charging  through 
the  thick  of  the  column  as  though  keeping  order  or  searching  for  a 
member  out  of  step  that  might  hinder  the  march.  All  is  magnificent 
order  and  system,  like  a  huge  splendidly  organized  army  of  soldiers, 
efficient  to  a  man  and  disciplined  into  machine-like  unity  of  action. 

By  mid-day  the  army  was  in  its  new  quarters,  encamped  and  ready 
for  the  next  march  or  hunt.  Meanwhile,  until  the  order  comes  to 
move,  there  is  much  to  be  done.  There  are  hundreds  of  eggs  and 
young  to  be  cleaned  and  cared  for.  They  must  be  guarded  and  fed 
and  kept  warm  lest  injury  result  and  the  future  of  the  tribe  be  endan- 
gered. 

As  they  clean  and  brush  the  youngsters,  the  nurses  gather  in  great 
clusters  throughout  the  camp,  one  upon  another,  sometimes  twenty 
deep  and  scattered  everywhere  among  this  living  mass  one  sees  the 
gleam  of  adolescent  insects.  All  about  them  move  other  members  of 
the  clan,  passing  in  and  out  among  the  company  streets,  each  bent 
upon  some  important  bit  of  work  that  collectively  forms  the  superb 
organization  before  us. 

They  accomplish  one  great  task  at  a  time,  eliminating  and  neglect- 
ing all  others,  which  at  other  times  would  claim  their  attention.  A 


120  INSECT  BEHAVIOR 

harvestman1  walks  calmly  about  among  the  seething  multitudes.  He 
is  undisturbed  and  quite  ignored  even  by  the  soldier  ants  that  sur- 
round the  nurses  and  rest  in  clusters  upon  the  walls  of  the  cavern.  A 
wasp  has  her  burrow  within  the  lines  also,  but  she  flies  in  and  out, 
bearing  prey  for  her  wasplets  at  will.  The  entrance  to  her  burrow 
is  within  half  an  inch  of  a  solid  phalanx  of  resting  ants.  Many 
others  are  moving  hastily  over  the  diggings  thrown  out  from  her 
nest,  but  none  enters  her  domain. 

They  are  a  moral  crowd  indeed,  these  army  ants.  Tomorrow  they 
may  seethe  forth  in  a  terrible  invasion  and  before  them  all  insects  will 
fall.  They  will  be  invincible,  merciless,  but  the  order  of  today  for- 
bids slaughter!  Within  their  very  camp  other  creatures  move  about 
at  will,  yet  the  ants  obey  that  strange  supreme  command  to  rest.  Fate 
is  with  the  wasp  and  harvestman. 

All  is  quiet  and  serene  about  the  camp.  There  are  no  signs  of  out- 
side activity  until  late  in  the  afternoon.  Then,  about  five  o'clock,  six 
lines  of  scouts  issue  from  the  cavern.  One  line  travels  out  to  the  posts 
of  Kalacoon  house,  another  to  the  west,  over  the  compound  in  the 
direction  from  whence  the  army  appeared.  Two  more  parties  go  to 
the  south  and  again  two  to  the  west  Each  of  these  lines  extends  for 
perhaps  fifty  feet.  They  form  in  single  file,  or  at  times  two  abreast, 
and  occasionally  a  line  may  be  seen  returning,  while  others  still 
advance. 

These  are  doubtless  scouting  parties,  searching  out  the  ground  to 
be  hunted  or  traveled  next.  There  are  no  warriors  among  them  until 
late  in  the  evening,  and  then  only  individuals  scattered  here  and  there 
by  the  wayside,  taking  no  part  in  the  activities  of  their  brothers.  The 
scouts  are  of  two  sizes,  both,  I  presume,  workers. 

Within  the  nest,  the  nurses,  and  somewhere,  hidden  from  the 
common  horde,  the  queen  still  rests,  attended  by  her  special  ants  in 
1 A  species  of  Phalangidea,  commonly  called  Daddy-Long-Legs. 


The  typical  dragon-fly  face,  showing  the  insects'  high-  A  robber  fly  with  its  prey.    This  insect  is  gifted  with 

ly  developed  eyes  and  negligible  antennae  or  comparatively  clear  eyesight.    Greatly  enlarged 

feelers.    Greatly  enlarged 


OBSERVATIONS  OX  AXTS  121 

waiting.  I  wonder  what  the  scouts  have  found,  what  they  have  noted 
and  communicated  in  their  mysterious  way  to  the  commander  of  this 
supreme  army.  It  is  growing  dark  without  and  the  scouts  abroad 
grow  less  numerous.  One  by  one  the  stars  appear  and  I  wait  as 
anxiously  as  an  expectant  enemy  for  the  morrow  and  the  outcome  of 
the  gigantic  plan  already  formulating  among  those  seething  hordes  in 
the  encampment. 

At  dawn  on  the  following  day,  I  found  the  army  at  its  work  of 
slaughter.  Walking  by  the  forest  trail,  I  was  suddenly  arrested  by 
a  strange  sound.  It  wras  not  the  sharp  noise  of  snake  or  lizard  startled 
by  my  approach,  nor  the  scratching  of  some  hungry  ant-bird.  It  was 
a  faint,  but  steadily  increasing  crackling  murmur,  unlike  all  other 
jungle  sounds. 

Stopping  to  listen,  with  ear  bent  to  the  brush,  my  eye  caught  sight 
of  a  line  of  warrior  ants.  Their  heads  were  huge  rounded  knobs, 
bearing  curving  mandibles  far  out  of  proportion  to  the  remainder  of 
their  bodies.  Glancing  back  along  this  line  of  soldiers,  I  soon  under- 
stood the  meaning  of  that  strange  cracking  murmur,  for  there  just 
behind  these  pickets  rolled  the  main  hordes  of  the  army  ants. 

Hundreds  and  thousands,  countless  myriads  of  them  rushing  ahead 
behind  their  leaders.  Some  were  in  rows,  others  in  bands,  chains  and 
semi-circles.  Among  them  were  warriors  of  two  sizes,  but  these 
were  outnumbered  a  hundred  to  one  by  the  workers  of  the  tribe,  who 
rushed  along  with  the  others. 

Every  blade  of  grass,  every  stone  and  twig  and  leaf  was  searched 
and  researched  by  these  fierce  creatures  in  their  mad  onward  journey. 
They  came  to  a  large  stump  and  seethed  up  it  in  a  solid  mass  like  thick 
flowing  molasses ;  up  one  moment,  down  the  next  and  on  to  another 
object,  whatever  it  might  be.  Thousands  of  others  mounted  to  the 
leaves  of  flowers  and  the  foliage  of  small  trees,  sending  down  a  shower 
of  panic-stricken  insects  to  the  waiting  crowds  below. 


122  INSECT  BEHAVIOR 

No  living  thing  turned  to  give  battle.  Outnumbered  a  thousand  to 
one  none  could  combat  such  overwhelming  odds.  Ahead  of  the 
army  rushed  dozens  of  insects,  driven  from  their  habitats  and  fleeing 
like  animals  before  a  forest  fire.  Some  would  escape  by  a  miracle, 
but  the  rule  was  a  few  short  hops  or  springs  and  then  death  at  the 
hands  of  the  multitude.  There  were  roaches  and  crickets,  big  cater- 
pillars and  beetles,  ants  of  other  species,  bugs  and  huge  centipedes  and 
great  numbers  of  spiders  all  fleeing  for  their  lives. 

Roaches  and  spiders  were  sought  in  particular.  They  appeared  to 
be  first  choice.  They  were  torn  to  shreds  at  once  and  carried  away  in 
still  squirming  pieces  to  the  nests.  Caterpillars,  if  hairless,  were  also 
in  favor,  then  spiders,  bugs  and  so  on  down  the  list  to  the  less  palatable 
creatures. 

What  I  had  heard  at  first  was  not  the  roar  of  the  army  itself,  but 
rather  the  fleeing  host  of  other  insects  driven  from  their  lairs.  I  saw 
one  large  spider  escape  death  by  a  hair's  breadth,  by  jumping  at  the 
instant  of  capture  from  a  leaf  into  the  air  and  there  hanging  by  a 
silken  thread  until  the  danger  had  passed.  Other  insects  that  occa- 
sionally escaped  were  crickets  and  grasshoppers,  their  powerful 
springing  legs  carrying  them  beyond  the  line  of  march.  A  curious 
fact  was  that  the  ants  never  crossed  the  more  deeply  trodden  footpath 
in  the  center  of  the  trail,  consequently  those  refugees  who  were  for- 
tunate enough  to  pass  this  line,  were  safe,  and  escaped  unmolested. 

A  large  roach  endeavored  to  escape  by  crossing  the  main  front  of 
the  army.  The  creature  made  several  powerful  jumps,  but  each 
time  it  touched  the  ground  in  order  to  make  another  spring,  its  legs 
were  grasped  by  the  fearless  ants  until  at  length  their  added  weight 
became  too  great  for  the  roach  to  lift.  In  the  end  it  fell,  after  a  brave 
effort  to  be  free,  and  was  instantly  torn  to  bits  and  carried  to  the  rear. 

Upon  being  captured  and  divided,  the  unfortunate  victim  is  at  once 
carried  back  through  the  lines  to  the  temporary  nest  of  the  colony. 


Photomicrograph  through  the  eye-windows  of  a  fly,  of  an  ex- 
ternal object,  placed  extremely  close  to  the  eye 

A  photomicrograph  through  the  same  eye,  of  the  same  object, 

moved  a  very  slight  distance  further  from  the  eye-windows,  but 

not  so  far  as  to  be  out  of  focu-,  when  viewed  alone 


OBSERVATIONS  ON  ANTS  123 

One  sees  an  unbroken  line  of  these  returning  warriors,  each  with  its 
dainty  bit  of  the  spoils.  If  the  captive  is  too  large  for  one  ant  to 
carry  conveniently,  it  is  distributed  in  steaks  and  hams  and  then 
brought  to  the  den  by  a  dozen  individuals.  I  saw  one  ant  struggling 
towards  the  nest  with  a  large  span-worm.  It  was  far  too  heavy  for 
her  to  transport  alone  and,  perceiving  this,  a  second  individual 
stopped  to  give  assistance.  After  some  difficulty,  these  two  insects 
slung  the  worm  between  their  legs,  stretched  it  to  its  full  length  and 
by  grasping  it  in  their  mandibles  proceeded  to  the  rear. 

Another  ant  with  the  body  of  a  wood  roach  was  assisted  by  a  worker 
who  held  the  carrier's  abdomen  high  in  the  air  out  of  the  way  of  her 
burden,  all  the  way  to  the  nest. 

In  observing  the  movements  of  the  army  I  became  so  absorbed,  that 
the  ants  surrounded  me  without  my  being  aware  of  it.  They  threw 
their  lines  here  and  there  through  the  jungle  for  a  distance  of  two  or 
three  hundred  feet  in  every  direction,  and  while  I  was  in  no  danger, 
I  could  not  get  beyond  their  rear  guards  without  being  attacked  and 
severely  bitten.  As  I  crossed  through  them  with  all  haste,  they 
swarmed  upon  my  shoes  and  socks,  biting  and  stinging  wherever  they 
could  get  through  to  the  skin. 

The  attack  of  these  vile  little  creatures,  whom  I  learned  to  hate 
worse  than  anything  else  in  the  jungle,  was  so  painful  and  poisonous 
that  I  shall  never  forget  it.  It  brought  home  to  me,  how  horrible 
must  have  been  the  deaths  of  those  poor  black  men  of  Africa,  who,  in 
punishment,  were  tied  hand  and  foot  and  left  in  the  path  of  the  army 
ants! 

It  is  a  strange  fact  that  many  other  insects  were  attracted  rather 
than  frightened  away  by  the  army's  movements.  There  were  various 
species  of  preying  wasps,  who,  finding  their  favorite  victims  of  cater- 
pillars and  spiders  abundant,  and  already  hunted  from  cover  for  them, 
were  quick  to  take  advantage  of  conditions.  They  would  hover  above 


i24  INSECT  BEHAVIOR 

the  army  like  hawks,  suddenly  diving  like  lightning  upon  some  dainty 
morsel  with  which  to  provision  their  nests. 

Likewise  there  were  flocks  of  birds,  thus  gaining  a  living  at  the 
expense  of  the  ants  who  drove  forth  their  favorite  insects.  Some 
were  tiny  species,  impertinent  and  talkative  and  sombre  in  color, 
others  were  larger,  decked  with  crests  of  snow  white  plumes.  One 
learned  to  associate  these  birds  and  insects,  for  where  a  flock  of  one 
was  heard  the  other  was  sure  to  be  also. 

For  many  hours  I  watched  this  army'at  its  deadly  work.  Then  at 
length  the  fury  of  their  drive  diminished.  One  by  one  the  warriors 
made  their  way  to  the  temporary  den  in  the  heart  of  a  rotting  forest 
giant  and  by  afternoon  no  signs  of  activity  remained  upon  the  forest 
floor. 

Would  that  I  might  have  seen  within  that  aged  and  broken  tree, 
for  there,  no  doubt,  a  royal  banquet  was  in  progress.  Perhaps 
another,  more  fortunate  than  I,  may  some  day  tell  us  what  goes  on, 
when  the  tired  warriors  return  laden  to  their  queen.  My  notes  are 
but  a  drop  in  the  bucket,  and  the  army  ants  have  still  much  to  tell  us. 


'A  harvestman  walks  calmly  about  among  the  seething  multitudes."    (Page  90.)    Greatly  enlarged 


The  ivory-colored  eggs,  massed  in  the  feathers  or  fur  of  the  respective  host,  hatch  within  twenty-four  hours.    A 

cluster  of  greenbottle's  eggs.    Greatly  enlarged 


CHAPTER  XV 

THE  SIGHT  OF  INSECTS 

OFTEN  we  have  wondered  to  what  extent  the  sense  of  sight 
is  developed  in  insects.  It  has  been  asked  again  and 
again.  It  has  been  argued  from  every  possible  standpoint, 
but  for  all  that  it  has  been  answered  slovenly,  and  in  an 
unsatisfactory  manner. 

Casual  observations  of  the  insect  world  tend  rather  to  convince  us 
that  its  people  are  alert  to  movements  and  dangers,  and  therefore  clear 
of  vision.  We  observe  the  male  of  a  species  searching  for  his  mate. 
Perhaps  she  is  a  foot  or  more  away,  hidden  behind  thick  foliage.  Her 
color  blends  perfectly  with  her  surroundings,  yet  how  easily  after  a 
move  or  two  he  discovers  her  and  quickly  greets  her  with  his  love. 

Again  we  hear  a  tree  cricket,  shouting  his  melody  into  the  summer 
night.  Stealthily  we  creep  up,  step  by  step,  to  the  spot  from  whence 
the  tune  arises  only  to  have  it  cease  abruptly  at  the  instant  of  dis- 
covery. 

And  so  we  might  sight  a  thousand  cases  where  apparently  insects' 
vision  aids  them  in  a  successful  life.  The  bug  searching  its  mate,  the 
cricket  avoiding  discovery,  the  fly  escaping  its  everlasting  and  greatest 
enemy,  the  swat,  and  so  on  indefinitely. 

But  it  is  strange  how  modern  instruments  and  facilities  for  proper 
study,  knock  one's  pet  theories  in  the  head.  They  rather  take  the 
romance  out  of  things.  Surely  they  leave  no  room  for  imagination, 
but  after  all  the  truth  is  best. 

Insects  possess  sight,  it  is  true,  but  in  most  cases  it  is  not  in  a  highly 

125 


ia6  INSECT  BEHAVIOR 

developed  state.  In  order  to  understand  what  follows  we  must  first 
become  acquainted  with  the  typical  insect  eye. 

It  is  not  the  organ  we  generally  think  of,  as  one  sees  it  in  the  head 
of  a  man,  a  beast  or  bird,  but  a  compound  and  vastly  different  object. 
It  is  true  that  upon  examining  an  insect  closely  we  observe  two  large 
eyes,  one  set  on  either  side  of  the  head,  but  if  we  were  to  magnify  the 
outer  shell  or  cornea  of  these  protrusi9ns,  we  would  find  that  what 
appears  to  be  a  single  eye  is,  in  reality,  made  up  of  many  hundreds  of 
smaller  facets  or  microscopical  windows,  the  whole  resembling  in 
every  detail  the  exterior  of  a  piece  of  honeycomb. 

Behind  each  of  these  facets  is  an  independent  eye  element  of  a  com- 
plex nature  connected  with  the  optic  nerve,  so  that  each  tiny  window 
sees  that  part  of  the  external  object  that  is  directly  in  front  of  it.  In 
other  words,  whatever  the  insect  sees  is  separated  into  as  many  parts 
as  there  are  facets.  To  begin  with,  then,  we  learn  that  insects  prob- 
ably see  things  in  mosaic  patterns. 

Let  us  now  take  a  fresh  insect  and  place  that  part  of  its  eye  bearing 
these  tiny  facets,  under  the  microscope.  Through  the  instrument  we 
observe  a  honeycomb  sash,  in  which  the  cuticular  windows  are  set, 
and  which  appear  to  be  quite  transparent. 

By  the  aid  of  a  photomicrographic  apparatus,  that  is  to  say,  an 
arrangement  by  which  we  may  photograph  through  a  microscope,  we 
now  mount  a  minute  object  so  delicately  in  front  of  the  already 
mounted  eye,  that  by  peering  into  one  end  of  the  apparatus,  we  may 
actually  see  an  external  object  through  the  eye  of  an  insect.  We  are, 
so  to  speak,  inside  the  fly,  looking  out. 

For  this  object  a  feather  from  the  head  of  a  humming  bird  was 
chosen.  By  reason  of  its  very  minute  size  and  convenient  fan-shaped 
structure  it  proved  ideal  to  illustrate  the  qualities  of  focus  in  the 
insect's  eye. 

In  figure  64  we  see  the  result  of  the  first  photographic  experiment, 


Attracted  by  a  special  odor,  the  mother  flies  come  to  deposit  their  eggs.    A  greenbottle  laying  eggs  upon  the 

head  of  a  dead  sparrow. 


The  eggs  are  deposited  away  from  the  light,  among  the  feathers,  in  wounds  or  in  the  mouth  of  the  host.    Green- 
bottle  laying  eggs  in  a  starling's  bill.    Both  much  enlarged 


THE  SIGHT  OF  INSECTS  127 

in  which  the  feather  was  placed,  the  smallest  fraction  of  an  inch 
beyond  the  eye  window.  It  is  clear  and  in  perfect  focus,  even  show- 
ing the  smallest  scales  of  the  feather  in  fine  detail.  In  each  successive 
experiment  the  feather  was  moved  perhaps  one  micron  further  from 
the  eye,  the  result  being  that  its  plumes  rapidly  lost  focus  until  all 
detail  was  gone.  This  was  in  no  way  due  to  the  use  of  a  too  powerful 
lens,  as  proved  by  the  fact  the  feather  remained  in  fair  focus  when  by 
itself  at  a  similar  distance  from  the  lens,  only  becoming  blurred  when 
viewed  through  the  cuticular  windows  of  the  eye. 

From  these  not  over-difficult  experiments  we  have  the  following 
facts  concerning  the  power  of  sight  in  insects.  In  the  first  place  they 
see  objects  in  mosaic  patterns.  Objects  are  seen  in  clear  focus  only 
when  extremely  close  to  the  eye.  At  greater  distances,  only  the  out- 
line of  the  object  is  visible  and  beyond  a  few  inches  things  doubtless 
pass  into  mere  shadows  with  intervening  patches  of  light. 

Further  the  experiments  tell  us  that  an  insect  cannot  always  depend 
upon  its  eyes.  To  find  its  mate,  and  to  sustain  life,  by  securing  food, 
it  must  rely  upon  the  sense  of  smell.  But  what  of  the  fly  who  even 
with  its  defective  eyesight,  still  avoids  your  swat  so  easily?  True,  he 
cannot  see  you  in  clear  outline,  but  remember  that  you  appear  to  him 
as  a  gigantic  shadow  more  reaching  than  that  cast  by  a  range  of  lofty 
mountains.  When  you  make  your  swat,  this  great  shadow  topples 
toward  him  with  fearful  speed,  but  Nature  has  supplied  the  creature 
with  eyes  that  exaggerate  and  a  speed  that  excels  a  falling  avalanche. 
^  Now  it  might  be  argued  that  these  experiments  were  not  really  per- 
formed with  the  actual  eye  of  an  insect,  but  simply  with  the  outer 
coating  of  that  organ,  and  therefore  prove  nothing.  Perhaps,  in  part 
such  a  statement  wrould  be  true,  yet  is  it  not  the  outermost  window 
that  governs  the  quality  of  sight?  A  man  might  possess  perfect 
vision,  yet  were  he  to  stand  with  his  face  against  a  dirty  window  his 


128  INSECT  BEHAVIOR 

eyes  would  avail  him  nothing  and  he  would  be  ignorant  of  the  details 
of  what  passed  without. 

And  so  with  the  insect,  I  believe  it  is  the  glass  in  the  tiny  honey 
comb  sash  that  governs  its  sight;  and  through  these  minute  windows 
the  photographs  illustrating  this  article  were  taken.  Whether  we 
observe  this  through  a  microscope,  as  we  have  done,  or  with  a  hand 
glass  or  the  naked  eye,  we  will  arrive  at  the  same  results  that  we  have 
already  seen  by  our  experiments. 

Doubtless  some  insects  see  more  clearly  than  others.  Crickets 
jump  at  the  slightest  movement  of  an  object  many  feet  away  and 
appear  to  be  so  gifted.  The  robber  fly  1  captures  its  prey  upon  the 
wing,  darting  after  it  as  it  passes  by,  but  of  all  these  creatures  who 
use  their  eyes  to  advantage,  the  dragon  flies  are,  in  the  opinion  of  the 
writer,  the  only  insects  who  depend  more  upon  their  eyes  than  any 
other  of  their  sense  organs. 

Dragon  flies  are  primarily  predacious  creatures,  feeding  chiefly 
upon  mosquitoes,  gnats,  house  flies  and  other  alert  and  winged  insects. 
They  dart  upon  their  prey  with  the  ease  and  swiftness  of  a  hawk,  often 
from  a  great  distance,  seldom  missing  their  unfortunate  quarry.  A 
glimpse  at  the  typical  dragon  fly  race,  strengthens  the  theory  that  they 
are  possessors  of  accurate  eye  sight.  The  eyes  are  huge,  covering  two- 
thirds  of  the  creature's  head,  while  the  antenna?  or  feelers,  which  are 
the  usual  sense  organs  of  direction  in  insects,  are  scarcely  noticeable, 
hair-like  appendages.  To  connect  these  primary  features  with  the 
creature's  habits,  can  only  lead  to  one  conclusion — that  the  dragon 
flies  are  possessed  of  clear  eye  sight  and  are  exceptions  to  the  general 
rule. 

1Asilidae.     See  Fig.  66. 


re  -. 

I-  J> 

a  N 

ex  35 


o    g 

o     !> 

%    *- 


S    o 

•fi  > 


CHAPTER  XVI 

HOW  THE  GREENBOTTLE  DOES  ITS  DUTY 

Sarcophagida 

AS  we  stroll  by  the  roadside  this  bright  morning,  a  breath  of 
air  brushes  ever  so  slightly  across  our  path.     It  is  a  breeze 
at  first  scented  with  blooming  roses  and  wistaria,  perfume 
gathered  from  who  knows  where,  and  born  by  chance  to  our 
nostrils.     In  an  instant  it  passes  on  as  mysteriously  as  it  came,  leaving 
us  bewildered  by  its  change  to  the  offensive.     It  is  no  longer  pleasing. 
Somewhere  within,  it  hits  a  tiny  blow  that  says  decay.     A  moment 
ago  we  had  forgotten  that  such  a  thing  were  possible,  but  we  are 
awakened  now  quite  rudely.    Even  today,  when  Nature  displays  her 
beauty  in  a  thousand  different  colors  and  voices  her  mood  in  as  many 
varied  songs,  there  is  such  a  thing  as  decay. 

Exploring  the  realm  of  thought  for  a  moment,  we  wonder  why  the 
shell  of  what  was  life,  no  matter  how  tiny,  no  matter  how  great,  if  left 
uncovered,  offends  us.  There  must  be  an  explanation  to  this,  for 
Nature  does  not  create  a  condition  or  a  state  without  a  reason.  Being 
human,  and  therefore  curious,  we  hunt  about  with  this  thought  in 
mind,  first  for  the  source  of  the  odor.  Its  function  we  shall  look  into 
later. 

Lying  stiffly  by  the  roadside,  the  result  of  human  folly  and  igno- 
rance we  find  the  offending  corpse,  a  tiny  squirrel  with  lustrous  coat, 
marred  only  by  the  wound  that  caused  its  death.  A  broken  stick  and 
an  empty  shotgun  shell  close  by  tell  the  story  of  the  crime,  sufficient 
evidence  to  convince  if  not  convict. 

Turning  over  the  little  animal,  we  find  a  surging  mass  of  maggots, 

129 


130  INSECT  BEHAVIOR 

a  sea  of  life  thriving  upon  death.  They  are  the  offspring  of  the 
greenbottle  flies  that  hover  about.  Here  indeed  is  food  for  thought. 
A  repulsive  sight  perhaps,  but  let  us  forget  about  that  part  of  it,  in 
order  to  realize  the  beauty  of  what  Nature  is  accomplishing. 

Nature  has  long  since  learned  that  she  cannot  rely  upon  Man  to 
restore  the  life  that  he  has  taken  nor  even  to  erase  his  crime  by  burying 
the  corpse,  yet  she  cannot  tolerate  the  sight  of  death.  If  she  did  our 
land  would  be  strewn  with  the  mummies  of  ages.  She  cannot  bury 
her  creatures  unaided.  Instead  she  sends  broadcast  her  tainted 
messengers,  who  marshal  others  to  her  aid.  Thus  we  see  her  reason 
for  the  odor  of  decay. 

Attracted  by  this  special  odor,  the  mother  flies  come  from  far  and 
near  to  deposit  their  eggs,  thus  securing  the  future  of  their  race. 
Hundreds  upon  hundreds,  thousands  upon  thousands  are  deposited 
and  hatched  until  a  great  army  is  mobilized  upon  whom  Nature  may 
rely.  In  a  short  time  that  which  was  but  a  mass  of  something  dead 
and  repulsive,  becomes  the  separate  bodies  of  myriad  living  creatures. 
Every  atom  of  the  squirrel  disappears  and  becomes  a  part  of  a  new 
life.  True,  the  squirrel's  bones  remain,  but  they  are  mineral  matter. 
They  will  go  back  into  the  earth  where  they  belong  and  Nature  will 
have  restored  her  balance. 

Examining  one  of  the  maggots,  we  find  it  to  be  a  soft-bodied 
creature,  milk  colored,  with  a  head  somewhat  darker  than  the  rest  of 
its  body.  It  is  tapered,  like  a  kernel  of  corn  viewed  sidewise,  the  head 
appearing  at  the  narrowest  end,  and  is  capable  of  a  rapid  rippling 
motion  by  contracting  and  expanding  its  muscles.  At  birth  it  is  no 
larger  than  a  flattened  pinhead  and  at  no  time  during  its  life  is  it  sup- 
plied with  mandibles  or  other  appendages  suitable  for  tearing  or 
masticating  its  food.  The  mouth  is  soft  and  extremely  minute ;  there 
are  no  sharp  claws,  no  teeth.  In  fact  it  possesses  nothing  but  two 
weak  lips  that  could  scarcely  caress  their  host.  How  then  does  such 


r       9 

3fe 


•  — X* 

\#*^P 


Skeleton  of  a  muskrat 
How  the  young  flies  clean  up  a  dead  animal,  leaving  only  the  bones  which  go  back  into  the  earth  as  mineral  matter 


From  left  to  right  the  tubes  contain,  banana,  coral  fungus,  boletus  fungus,  sugar,  gluten,  yolk  of  egg,  white  of  egg 
and  cheese.     Each  tube  contains  ten  young  greenbottle  flies  who  were  observed  to  thrive  on  these  fresh- 
foods.     Note  liquification  of  foods  in  tubes  5,  6  and  7 


HOW  THE  GREENBOTTLE  DOES  ITS  DUTY     131 

a  weakling  surmount  the  difficulties  of  feeding  upon  the  toughened 
corpse?  To  answer  this  we  must  experiment  in  the  laboratory. 
Such  a  question  cannot  be  decided  by  theory.  We  must  secure  the 
eggs  of  the  fly,  hatch  them  under  various  conditions  and  note  what  we 
can  of  their  methods. 

For  our  purpose,  we  place  several  dead  objects  in  the  sunlight.  In 
a  very  short  while  there  are  a  dozen  flies  about  the  game.  Soon  there 
are  a  thousand  ivory  eggs,  and  in  a  day,  as  many  wriggling  offspring. 
The  first  experiment  is  a  huge  success.  We  have  a  multitude  of  eggs 
and  young.  Let  us  gather  some  and  continue. 

In  the  laboratory  we  prepare  twelve  cubes  of  fresh  raw  beef,  each 
weighing  three  grams.  Six  of  these  are  placed  in  separate  test  tubes 
with  cotton  stoppers  to  prevent  evaporation  and  a  dozen  freshly 
deposited  eggs  of  the  fly  are  added  to  each.  The  six  remaining  cubes 
of  beef  are  placed  under  a  glass  bell  as  a  control. 

In  a  short  time  the  inoculated  tubes  are  alive  with  young  flies  and 
we  notice  that  each  individual  is  constantly  surrounded  by  moisture. 
As  the  youngsters  increase  in  size  from  day  to  day,  the  puddle  in 
which  each  one  feeds  grows  in  proportion  until  at  length  after  five 
days  the  meat  within  each  tube  is  completely  liquefied  and  about  the 
consistency  of  thick  cream.  Under  the  glass  bell  conditions  are 
totally  different.  Here  the  meat  cubes  are  in  exactly  the  same  form  as 
when  placed  there  five  days  before.  Perhaps  they  are  slightly  darker 
in  color,  but  they  are  still  in  the  form  of  cubes  and  quite  as  solid  as 
ever.  There  is  nothing  which  suggests  a  liquid  state  such  as  we  see 
in  the  test  tubes  where  the  young  flies  have  been  feeding. 

Continuing  our  experiments,  we  dip  a  piece  of  blue  litmus  paper 
into  one  of  the  tubes  of  liquefied  meat.  It  turns  almost  at  once  from 
blue  into  a  faded  red.  This  is  a  simple  chemical  test  which  shows 
the  contents  of  the  tube  to  be  slightly  acid.  We  find  that  the  same 
is  true  of  the  six  inoculated  tubes.  Now  in  the  human  body  there 


132  INSECT  BEHAVIOR 

exists  a  ferment  in  the  gastric  juice  known  as  pepsin,  which  in  the 
presence  of  a  weak  acid  converts  proteids  or  tissue-forming  foods  into 
peptones,  that  they  may  be  easily  diffused  through  the  membranes  and 
used  in  the  actual  building  and  heating  of  the  body.  The  strip  of 
litmus  has  shown  us  the  presence  of  just  such  an  acid  in  each  tube  of 
liquefied  meat. 

Here  then  is  the  solution  of  the  mystery  surrounding  the  young 
flies'  method  of  feeding.  They  are  born  without  an  equipment,  suit- 
able for  actually  chewing,  but  Nature  has  supplied  them  with  a 
powerful  expectorant  capable  of  dissolving  flesh  into  bouillon.  Like 
so  many  drunkards,  they  drink  their  dinners,  but  their  intoxication 
which  comes  only  in  the  form  of  life,  rids  us  of  decay,  a  menace  to 
our  health  and  welfare. 

From  a  chemical  point  of  view,  the  young  greenbottles  digest  their 
food  in  much  the  same  manner  that  we  do,  but  being  unable  to  chew 
and  swallow  solids,  they  exude  their  pepsin  first  upon  the  food,  con- 
verting it  into  liquid,  which  is  then  easily  drawn  into  their  suckling 
mouths  and  swallowed.  Indeed  it  is  a  most  admirable  method,  one 
that  we  would  not  be  loath  to  mimic  were  our  jaws  undeveloped,  our 
mouths  toothless  and  our  limbs  unsprouted.  So  much  for  the  young 
flies'  method  of  assimilating  their  food. 

Let  us  make  the  final  experiments  so  that  we  may  realize  how  this 
insect  is  of  service  to  mankind.  There  are  fifty  thousand  species  of 
flies  and  we  cannot  condemn  them  all  like  the  filthy  house  fly  and  the 
fever  mosquitoes,  which  are  recognized  outlaws  of  humanity.  In  the 
ranks  of  this  huge  winged  army  we  find  insects  doing  good  as  well  as 
bad,  and  the  greenbottle  is  one  of  them. 

For  our  experiment  we  procure  a  banana,  two  kinds  of  fungi, 
some  granulated  sugar,  the  boiled  white  and  yolk  of  an  egg,  some 
gluten  and  a  bit  of  cheese.  It  is  a  weird  collection  to  be  sure,  but  it 
will  serve  our  purpose  very  well.  We  have  now  eight  different  food 


HOW  THE  GREENBOTTLE  DOES  ITS  DUTY     133 

materials,  fresh  and  wholesome  in  every  particular,  and  varied 
enough,  one  would  say,  to  suit  the  most  fastidious  taste.  Such  a  free 
lunch  should  tempt  the  most  abstemious. 

During  the  day  many  greenbottles  are  attracted  to  the  repast.  They 
find  the  lure  attractive  and  satisfying  to  their  own  mature  appetite, 
but  for  all  our  trouble  no  eggs  are  laid  upon  the  stores.  This  is 
indeed  mystifying.  Can  it  be  that  such  excellent  provender  is 
unworthy  of  the  fly's  offspring?  A  curious  state  of  affairs  this,  that 
such  a  puny  creature  must  reject  the  fats,  sugars,  proteids  and  other 
nutrients  capable  of  sustaining  life  in  man  himself. 

Let  us  collect  our  foods  and  place  each  in  a  separate  test  tube, 
previously  inoculated  with  a  number  of  young  flies.  The  youngsters 
are  not  half  so  particular  as  their  parents.  They  feed  happily  enough 
on  what  we  have  provided  and  the  tide  of  liquid  rises  rapidly  in  each 
tube.  The  egg,  the  fruit,  the  dry  gluten,  all  but  the  sugar  are  con- 
sumed with  relish  by  the  maggots. 

We  have  seen  that  the  mother  greenbottle  ignores  these  fresh 
foods  for  the  purpose  of  laying  her  eggs,  but  we  know  from  the 
experiment  just  performed  that  her  young  will  thrive  upon  them. 
Perhaps  this  is  common  knowledge  between  the  fly  and  ourselves,  yet 
she  selects  only  putrefying  matter  in  which  to  bear  the  fruit  of  her 
love,  that  our  world  may  be  saved  from  the  menace  of  decay. 

No  doubt  the  greenbottles  carry  germs,  no  doubt  they  bring  an 
occasional  sickness  to  those  who  come  in  contact  with  them,  but  unlike 
the  house  fly,  they  are  at  the  same  time  altruists,  working  for  the 
public  good.  Like  the  street  cleaner  and  the  hobo,  both  are  dirty, 
yet  one  is  a  menace,  while  the  other  rids  us  of  one. 


CHAPTER  XVII 

SOME  INSECT  EXPERIMENTS 

YONDER  near  the  forest's  edge,  a  neglected,  grass-grown 
wood  path  winds  its  silent  way  into  the  sombre,  shaded 
depths  of  the  virgin  growth.     In  the  center  of  the  path 
stands  a  mound  of  dry,  brown  earth,  protected  from  Na- 
ture's elements  by  the  thick,  dark  foliage  above.    The  mound  is  nearly 
three  feet  in  diameter  and  stands  some  eighteen  inches  in  height,  for 
all  the  world  like  a  miniature  volcano  in  a  setting  of  giant  trees. 
Indeed,  even  the  lava  seems  to  be  there,  pouring  downward  in  an  ever- 
changing  stream,  as  if  impatient  to  destroy  some  tiny  city  at  the 
mountain's  base.     But  this  is  not  the  eruption  of  a  fairy  Vesuvius, 
which  we  are  witnessing,  nor  is  it  even  an  unusual  sight,  but  simply 
a  great  thriving  insect  city,  wherein  live  some  forty  thousand  mound 
ants1  whose  unceasing  labors  cause  the  whole  metropolis  to  writhe 
lik  streams  of  molten  lava! 

Among  the  numerous  volumes  which  have  been  written  upon  insect 
life  we  seldom  find  one  in  which  the  ants  are  not  credited  as  being  the 
most  marvelous  of  all  insects.  The  actions  of  these  creatures  and  the 
deeds  which  they  accomplish  would  furnish  sufficient  material  to  fill 
many  a  volume  of  portly  size,  and  indeed  much  has  been  written  upon 
the  subject.  Marvelous  is  the  manner  in  which  they  feed  and  care  for 
their  young  and  wonderful  the  loyalty  of  the  subjects  to  their  queen 
and  their  city.  The  storing  of  proper  food  for  the  winter  and  the 
capturing  of  Aphids  or  "Milch  cattle,"  from  which  the  ants  extract 
a  sweet  nourishing  liquid,  are  other  interesting  examples,  all  of  which 

1  Formica  exsectoides. 

134 


Nest  of  the  mound-building  ants 
One-twelfth  natural  size 


SOME  INSECT  EXPERIMENTS  135 

tend  to  strengthen  one's  belief  in  the  intelligence  of  these  industrious 
inhabitants  of  our  world.  But  sooner  or  later,  the  very  insect  who, 
perhaps,  by  its  marvelous  actions,  has  held  our  rapt  attention,  or 
caused  us  to  exclaim  in  astonishment,  will  display,  but  a  moment 
later,  such  a  ridiculous  lack  of  logic  that  we  are  at  loss  to  understand, 
and  our  belief  in  intelligence  will  be  rudely  shaken.  But  perhaps  not 
permanently,  for  it  is  true  that  among  nearly  every  large  colony  of 
these  insects  one  will  find  an  occasional  example  wherein  an  individ- 
ual seems  really  to  leave  the  beaten  track  of  instinct  in  which  its 
forefathers  have  traveled  unwittingly  for  hundreds  and  hundreds  of 
years. 

Let  us  follow,  for  a  moment,  the  movements  of  a  single  member 
of  this  colony  of  mound-builders,  who  is  discovered  laboriously 
endeavoring  to  drag  the  remains  of  a  cricket  many  times  its  own  size 
to  the  insect  city,  some  twenty  feet  distant. 

In  the  same  circumstances,  a  man  would  have  soon  given  up  the 
task,  for  every  twig,  every  leaf  and  every  stone  in  the  path  played  a 
part  in  hindering  the  progress  of  the  hard-working  insect.  But  the 
ant  would  not  abandon  such  a  dainty  morsel  of  food,  even  had  it  been 
three  times  as  heavy,  and  indeed  she  might  have  soon  reached  her 
destination  had  I  not  cautiously  clasped  the  cricket  by  one  of  its 
antennae  or  feelers  with  a  pair  of  slender  forceps.  The  ant  was  greatly 
troubled  at  finding  her  burden  immovable,  but  she  soon  commenced  to 
investigate,  and  finally,  after  some  minutes,  came  upon  the  closed  end 
of  my  forceps.  Vainly  she  tried  to  free  the  insect  from  the  grip  of 
steel  and  finding  herself  unequal  to  the  task,  she  soon  made  off  in  the 
direction  of  the  mound.  Now  when  perhags  fifteen  inches  away,  the 
ant  suddenly  turned,  as  if  by  some  idea  or  impulse  which  must  be 
obeyed.  Going  straight  to  the  feeler,  which  was  still  held  by  the 
forceps,  she  chewed  it  free  with  her  powerful  jaws  and  once  more 
made  off,  this  time  in  possession  of  her  well-earned  burden! 


136  INSECT  BEHAVIOR 

Of  course  it  is  probable  that  upon  her  return,  the  ant  came  by 
accident  directly  to  that  part  of  the  cricket  which  was  being  held  in 
the  forceps.  Nevertheless,  it  must  be  remembered  that  this  time 
the  ant  freed  her  prize  by  chewing  through  the  cricket's  feeler,  an 
action  which  had  not,  apparently,  occurred  to  her  when  her  journey 
was  first  arrested.  Although  this  fact  is  not  a  very  remarkable  one, 
it  is  true  that  the  ant  was  efficient  in  adapting  herself  to  the  cir- 
cumstances, which  were  quite  unusual.  In  such  cases  instinct  is  sup- 
posed to  be  deficient. 

Now  let  us  watch  another  ant,  an  inhabitant  of  the  same  mound, 
who  is  also  struggling  homeward,  bearing  the  remains  of  some  dry 
and  lifeless  insect. 

After  towing  her  burden  backwards  for  perhaps  twelve  inches,  the 
insect  came  upon  a  tall  blade  of  grass,  fully  a  foot  in  height,  which 
was  growing  directly  in  her  path.  Here  I  expected  to  see  the  ant 
circumscribe  the  base  of  the  stem,  but  what  stupidity!  Instead  of 
executing  this  simple  manoeuvre,  she  climbed  first  to  the  top  and 
finally  down  again  upon  the  opposite  side  of  the  blade,  probably  with 
the  idea  that  she  had  covered  with  ease  a  considerable  portion  of  the 
homeward  journey. 

These  two  ants,  which  we  have  followed  with  their  burdens,  were 
undoubtedly  children  of  the  same  queen,  yet  while  one  was  quite 
competent  under  extraordinary  conditions,  the  other  lacked  sufficient 
power  of  perception  to  have  prevented  herself  from  accomplishing 
a  useless  feat. 

An  interesting  insect  for  experimental  purposes  is  the  Sphecid 
wasp,1  the  largest  and  most  powerful  of  our  Eastern  wasps.  This 
insect  digs  a  deep  burrow  in  sandy  soil,  at  the  end  of  which  two  or 
more  elongated  chambers  or  cells  are  constructed.  In  each  of  these, 
the  insect  places  a  single  cicada  or  "Locust"  that  has  previously 

1  Sphecius  speciosus. 


SOME  INSECT  EXPERIMENTS  137 

been  paralyzed,  but  not  killed,  by  the  wasp's  terrific  sting.  Now  she 
lays  an  egg  upon  the  breast  of  each  of  the  unfortunate  cicadas.  When 
this  has  been  done  the  burrow  is  sealed  with  earth  and  the  young 
wasps  feed  upon  the  paralyzed  insects  until  they  reach  what  is  known 
as  the  pupal  state.  In  this  form  they  spend  the  winter,  issuing  as 
perfect  insects  in  the  following  spring.  (See  chapter  XI.) 

It  is  true  that  the  cicada  is  larger  and  heavier,  even  than  the  power- 
ful Sphecid,  and  it  will  readily  occur  to  the  reader,  that  to  carry 
such  an  ungainly  burden  through  the  air,  would  be  an  extremely 
difficult  undertaking.  But  here  Nature  has  assisted  the  insect  in  ac- 
complishing her  function  by  supplying  a  pair  of  powerful  upturned 
hooks  or  tongs,  one  of  which  is  situated  upon  the  under  side  of  each 
of  the  wasp's  back  legs.  These  she  squeezes  against  the  cicada's  sides 
and  thus  secures  her  burden  during  the  overland  journey  to  the 
burrow. 

During  the  latter  part  of  August,  the  writer  captured  one  of  these* 
insects,  together  with  a  cicada,  which  it  had  recently  paralyzed.  The 
carrying  hooks  were  then  carefully  removed  from  the  Sphecid's  legs 
and  after  several  hours,  the  insect  was  replaced  beside  the  same  cicada 
which  it  had  been  carrying  when  captured.  This  was  within  a  few 
feet  of  the  burrow.  Now  a  remarkable  thing  happened.  The  wasp 
paid  not  the  slightest  attention  to  the  cicada,  but  flew  rapidly  away 
among  the  trees.  This  I  had  expected,  but  to  my  surprise  she  re- 
turned to  the  burrow  within  an  hour,  carrying  another  victim,  appar- 
ently in  her  first  and  second  pairs  of  legs.  The  cicada  was  suspended, 
tail  down,  in  a  line  perpendicular  to  the  wasp's  body;  the  two  insects 
forming  the  letter  T  while  in  the  air. 

This  is  a  most  remarkable  case,  as  the  Sphecid  left  the  instinctive 
rut  so  minutely  traveled  by  her  ancestors  and  instantly  adapted  her- 
self to  the  most  extrinsic  circumstances  imaginable. 

Equally  interesting  are  the  results  of  two  experiments  upon  differ- 


138  INSECT  BEHAVIOR 

ent  species  of  the  same  group  of  insects,  which  were  recently  observed 
at  close  range  by  the  author.  These  experiments  are  well  worthy 
of  note,  from  the  fact  that  a  vast  contrast  in  adaptability  was  discov- 
ered between  two  insect  species,  so  entirely  identical  in  their  anatomi- 
cal structure  and  so  closely  related  in  their  classification  that  they 
should  have  been  equal  to  each  other,  even  under  the  unusual  cir- 
cumstances in  which  they  were  placed.  Yet  in  one  of  these  experi- 
ments it  was  shown  that  a  certain  species  possessed  the  power  of  in- 
stantly distinguishing  between  right  and  wrong,  while  the  other  made 
plain  its  inability  to  leave  the  beaten  path  of  innate  propensity. 

As  I  have  said,  the  insects  in  question  were  both  species  of  wasps; 
one  the  common  paper  wasp  x  and  the  other  the  common  blue  mud- 
dauber.2 

Although  they  are  much  alike  in  structure,  their  habits  are  quite 
at  variance,  as  we  shall  presently  see. 

The  paper  wasps  are  a  social  species;  that  is,  they  live  in  a  colony, 
with  a  common  den,  which  in  this  case  consists  of  a  group  of  paper 
tubes  for  cells  suspended  by  a  central  stem  from  the  undersides  of 
overhanging  stones  or  more  often  from  old  beams  and  timbers  in 
barns  or  sheds.  The  paper  for  the  nest  is  manufactured  by  the  wasps 
from  wood  pulp,  which  is  scraped  from  unpainted  lumber  and  then 
mixed  with  a  glutinous  substance,  which  the  insects  possess.  A  large 
nest  will  contain  in  the  neighborhood  of  three  hundred  cells,  but  the 
great  majority  are  complete  when  one  hundred  have  been  constructed. 
In  each  of  these  cells  an  egg  is  laid  by  the  queen  and  the  young  are 
fed  by  the  other  members  of  the  colony  until  their  period  of  help- 
lessness is  at  an  end.  Their  food  consists  of  chewed  up  spiders  and 
other  insects,  mixed  with  a  certain  amount  of  nectar,  and  is  un- 
doubtedly good.  Thus  it  will  be  seen  that  the  paper  wasps  are  of  a 

1  Polistes. 

2  Chalybion  caeruleum. 


Cecropia  caterpillars  twenty-five  days  old.    Life  size  Twenty-six  day  old  cecropia  caterpillar  casting  its 

skin.    Life  size 


Caterpillars  of  the  cecropia  moth  just  after  the  second  Eggs  of 

cast.    Reduced 


an  apple  leaf.    Natural 


SOME  INSECT  EXPERIMENTS  139 

domestic  turn  of  mind,  and  quite  different  in  habits  from  their  mud- 
daubing  cousin,  who  is  a  restless,  nervous  creature  of  a  solitary  nature. 

.This  insect  constructs  from  five  to  fifteen  cells  of  rich  grey  mud, 
which,  upon  hardening,  becomes  quite  substantial.  The  nest  is  placed 
in  situations  similar  to  those  which  the  paper-making  species  select. 
Like  the  Sphecid  wasp,  the  mud-dauber  fills  each  cell  with  paralyzed 
insects,  which  in  this  case  consist  of  small  spiders.  Then,  after  laying 
a  single  egg  in  each,  she  seals  up  the  opening  with  mud  and  leaves 
the  young  wasps  to  shift  for  themselves. 

For  the  first  experiment,  a  mud-dauber's  nest  was  selected  which 
was  discovered  under  the  overhanging  roof  of  an  old  woodshed.  The 
affair  consisted  of  ten  cells,  all  but  one  of  which  had  been  sealed  by 
the  wasp,  who,  by  the  way,  quickly  appeared  upon  the  scene,  carrying 
a  small,  reddish  spider.  The  burdened  insect  flew  directly  to  the 
nest  and  after  carefully  inspecting  her  cargo,  to  make  sure  that  it 
was  in  perfect  condition  and  quite  proper  to  serve  as  food  for  her 
offspring,  she  entered  the  remaining  empty  cell.  To  store  these  spiders 
to  her  satisfaction  required  quite  some  time,  but  when  once  they  had 
been  suitably  placed  our  industrious  insect  lost  no  time  in  hurrying 
away  to  gather  more  victims.  This  manoeuvre  was  repeated  on  an 
average  of  every  seven  minutes,  but  upon  her  tenth  return  to  the  nest, 
she  carried  a  small  pellet  of  mud  instead  of  the  usual  spider.  This 
she  carefully  placed  upon  the  open  end  of  the  cell  and  after  flattening 
it  somewhat  with  her  head  and  forefeet,  flew  off  for  more. 

At  this  point  I  intervened  in  behalf  of  my  experiment,  and  as  a 
consequence  thereof,  the  sealed  portion  of  the  entrance,  and  the  spi- 
ders, were  entirely  removed  from  the  cell.  Within  a  very  few  minutes 
the  wasp  returned,  bearing  its  second  load  of  mortar,  and  this,  as 
upon  her  previous  visit,  she  cemented  to  the  opening  of  the  cell.  Now 
the  wasp  thrust  her  head  through  the  half-closed  entrance  and  after 
apparently  inspecting  the  empty  interior,  again  flew  away,  this  time,  I 


INSECT  BEHAVIOR 

thought,  in  search  of  a  new  supply  of  spiders.  But  this  was  not  the 
case,  as  we  shall  see.  I  now  left  the  immediate  locality  of  the  nest, 
fearing  that  perhaps  my  continued  presence  would  alarm  the  subject 
of  my  experiment.  In  an  hour  I  returned,  only  to  find  that  the  wasp 
had  ignored  the  fact  that  the  cell  had  been  emptied  and  had  com- 
pletely resealed  it  without  replacing  the  spiders  or  her  egg. 

In  this  case  the  insect  clearly  demonstrated  her  inability  to  notice 
even  such  a  radical  alteration  as  had  been  made  in  the  cell  contents 
during  her  short  absence.  She  simply  proceeded  to  accomplish  a 
certain  regular  course  of  inborn  events  and,  owing  to  the  fact  that  it 
did  not  occur  to  her  to  alter  any  of  these,  even  under  the  present  cir- 
cumstances, it  is  plain  that  there  existed  nothing  in  the  form  of  in- 
telligence, but  simply  innate  muscular  actions  of  a  reflective  or  un- 
conscious nature. 

But  now  let  us  turn  to  the  subject  of  my  last  experiment,  which,  it 
will  be  remembered,  was  the  closely  related  paper-making  cousin 
of  the  mud-dauber.  As  I  have  stated  before,  the  paper  wasps  do 
not  seal  up  their  cells,  nor  do  they  even  store  them  with  nourishing 
food  for  the  young.  Owing  to  this  state  of  affairs,  it  would,  of  course, 
be  impossible  to  effect  a  similar  alteration  upon  their  nest  as  upon  that 
of  the  mud-dauber.  But  the  purpose  of  my  experiments  was  not  sim- 
ply to  place  the  two  species  in  identical  circumstances,  but  to  dis- 
cover, if  when  placed  under  extraordinary  conditions,  either  would 
display  in  their  actions  any  evidences  of  intelligence;  or  in  fact  any- 
thing which  might  give  us  better  reason  for  believing  that  insects  are 
sometimes  governed  by  a  power  above  mere  instinct. 

At  the  time  of  this  experiment,  the  paper  wasps  were  adding  sev- 
eral new  cells  to  the  nest,  which  had  grown  too  small  for  the  rapidly 
increasing  colony.  These  new  cells  were  nearly  finished ;  all  but  one, 
and  of  this  perhaps  a  third  had  been  constructed  by  the  tireless  in- 
sects. As  I  reached  the  nest,  a  wasp  was  seen  working  upon  the  un- 


SOME  INSECT  EXPERIMENTS  141 

finished  cell,  but  she  soon  flew  away  in  search  of  a  new  supply  of 
pulp.  When  she  had  gone  far  enough  to  insure  my  feelings  against 
her  sting,  the  other  members  of  the  colony  were  quickly  put  aside 
and  the  cell  was  then  suddenly  finished  by  human  hand,  assisted  by 
a  small  tube  of  greyish  court-plaster. 

In  a  few  minutes  the  wasp  returned  and  flew  directly  to  the  cell 
which  I  had  so  kindly  completed  for  her.  But  she  apparently  con- 
sidered my  work  as  being  far  from  the  required  standard,  indeed  she 
must  have  thought  me  downright  fresh,  for  soon  my  carefully  made 
cell  of  court-plaster  was  cut  away  from  the  nest  and  viciously  ejected 
by  the  wasp,  who  was  now  in  a  temper  to  be  respected. 

On  the  following  day  I  returned  to  the  nest  with  another  cell, 
but  this  time  I  had  moulded  it  of  papier-mache;  thus  it  was  identical 
in  size,  color  and  texture,  with  those  which  the  wasps  construct 
themselves.  Once  more  the  wasps  were  put  out  of  the  way,  and  while 
the  one  who  had  been  allowed  her  freedom  upon  the  previous  day 
was  again  collecting  pulp  at  a  respectful  distance,  I  cut  away  the 
cell  which  was  now  nearly  finished,  and  fastened  the  papier-mache 
one  in  its  place.  Upon  her  return  to  the  nest,  the  wasp  displayed 
the  same  disgust  at  my  inability  to  construct  a  cell,  as  upon  the  oc- 
casion of  my  original  effort.  Consequently  the  object  of  my  labors 
met  a  fate  similar  to  that  which  the  first  cell  was  subjected  to! 

How  quickly  this  insect  recognized  the  uselessness  of  these  man- 
made  cells,  for  indeed  I  had  left  them  open  at  both  ends.  Yet  her 
very  near  relative,  the  mud-dauber,  was  blind  to  the  fact  that  her 
nest  cell  had  been  trifled  with  and  her  egg  removed,  which  is  an  affair 
of  much  greater  importance!  But  why  these  differences,  even  among 
insects  almost  of  the  same  flesh  and  blood?  That  is  what  we  do  not 
know;  it  is  a  question  for  which  we  have  yet  to  find  an  answer.  But 
however  that  may  be,  it  is  evident  from  the  results  of  the  experiments 
which  I  have  just  described  that  in  cases  unlikely  to  be  provided  for 


142  INSECT  BEHAVIOR 

by  instinct,  insects  will  occasionally  adopt  means  whereby  their  ob- 
jects may  be  effected.  And  if  it  be  true,  as  we  now  believe,  that  all 
instincts  arose  through  successive  generations  preserving  habits  which 
happened  to  be  of  benefit,  then  insects  must  gain  knowledge  from  ex- 
perience, which  would  appear  to  be  impossible  were  they  not  gifted 
with  a  slight  amount  of  intelligence. 


Female  cecropia  moth.    Two-thirds  life  size 


Full  grown   cecropia  caterpillar  just   before  com- 
mencing its  cocoon.    Life  size 


Newly  completed  cocoon  of  the  cecropia  moth. 
Two-thirds  life  size 


CHAPTER  XVIII 


Samia  cecropia 

WHEN   the   first  fireflies   are   sparkling  here   and   there 
among  the  fresh  dark  foliage,   and  when   the   migrant 
warblers   from   the   Southland   have   ceased   to   fill   the 
evening  air  with  their  sharp  clear  voices,  it  is  then  that 
the  great  cecropia  moths  are  on  the  wing,  hovering  silently  among 
the  newly  opened  blossoms,  for  it  is  the  first  real  sultry  night  in  June. 
During  the  day  they  have  been  creeping  forth  from  their  big  winter- 
worn  cocoons  to  dry  their  wings,  long  cramped  and  matted.     But 
now  it  is  night,  it  is  time  to  venture  abroad  into  a  new  world,  perhaps 
to  mate  and  to  start  a  new  generation,  perhaps  to  enter  the  open  net 
of  an  eager  entomologist  or  perhaps  to  feed  some  hungry,  prowling 
animal. 

Soon  after  this  first  night  of  freedom,  the  female  moth  who  has 
been  fortunate  in  avoiding  its  enemies  is  ready  to  lay  her  eggs. 
These  are  deposited  in  small  white  clusters  upon  the  underside  of  the 
leaves  of  our  cultivated  fruit  trees.  Unfortunately  we  cannot  alter 
this  law  of  nature  and  thus  the  cecropia  must  fall  in  our  estimation, 
like  so  many  other  insects,  wonderful  and  beautiful  to  look  upon,  but 
"Noxious"  as  the  sentiment-lacking  entomologist  must  class  them. 
If  the  moths  would  confine  their  attacks  to  the  larger  trees,  such  as 
the  apple  or  pear,  the  cecropia  would  do  little  or  no  damage,  as  the 
moths  lay  but  a  few  eggs  upon  a  single  tree.  However,  when  these 
occur  upon  a  small  currant  or  other  fruit  bearing  bush,  as  they  fre- 
quently do,  it  is  but  a  very  short  time  after  the  caterpillars  hatch 

143 


144  INSECT  BEHAVIOR 

out  before  the  foliage  is  entirely  consumed.  The  bush  is  then  ruined 
until  the  following  spring. 

Ten  days  after  being  deposited  upon  the  food  plant,  the  eggs  split 
open  in  the  center.  One  unfamiliar  with  the  cecropia's  life  history 
would  be  very  much  surprised  to  see  the  tiny,  black-spined  cater- 
pillars which  emerge  from  them.  At  this  age,  they  are  jet  black  and 
scarcely  a  quarter  of  an  inch  in  length.  The  body  is  armed  with 
six  rows  of  eleven  and  sometimes  twelve  stout  spines,  which,  no 
doubt,  are  terrifying  enough  to  their  natural  enemies.  When  about 
five  days  old,  a  tiny  orange  ring  appears  around  the  base  of  every 
spine.  This  is  a  sign  that  the  larva,  as  the  caterpillar  is  scientific- 
ally termed,  is  about  to  cast  its  skin.  That  is  to  say,  it  has  grown 
too  large  for  its  birthday  suit  and  therefore  must  have  a  larger  one. 

The  cast  is  intensely  interesting  to  watch,  as  the  old  dry  skin  may  be 
seen  to  split,  at  first  near  the  head  and  finally  down  the  back  until 
it  reaches  a  point  directly  above  the  last  pair  of  legs.  At  this  juncture 
the  larva  simply  crawls  out,  bearing  a  new  suit  of  the  brightest 
yellow,  with  steel  blue  spines,  leaving  the  old  black  cast-off  sticking 
to  whatever  substance  the  larva  had  fastened  it  to. 

The  cecropia  caterpillar  grows  too  large  for  its  skin  four  times 
during  its  life,  shedding  each  time,  and  the  colors  changing  some- 
what with  every  cast.  The  last  moult  takes  place  when  the  larva  is 
twenty-six  days  old.  The  body  color  is  then  a  beautiful  deep  foliage 
green  and  the  spines  are  varied  in  orange,  yellow,  and  the  brightest 
imaginable  blue.  For  eleven  days  after  this  cast  the  giant  caterpillar 
goes  on  feeding  as  before,  finally  reaching  a  length  of  nearly  five 
inches  before  starting  to  spin  its  cocoon.  Indeed  at  this  period  of 
its  life,  it  is  hard  to  imagine  that  this  great  green  worm  could  be 
connected  in  any  possible  manner  with  the  tiny,  black-spined  larva 
of  thirty-seven  days  before. 

Although  defenceless,  the  cecropia's  protection  is  complete.     Its 


THE  CECROPIA  MOTH  145 

green  coloring  mimics  its  surroundings  closely.  It  is  all  but  invisible 
at  a  distance,  even  to  the  human  eye.  To  a  bird,  it  is  probably  en- 
tirely so.  When  a  bird  comes  upon  one  of  these  caterpillars  at  close 
range,  it  knows  only  too  well  that  it  is  on  dangerous  ground,  for  the 
gaudy  color  of  cecropia's  spines  actually  serve  to  inform  it  that  the 
creature  contains  poisonous  ingredients  and  is  not  fit  to  eat. 

When  the  larva  is  ready  for  its  cocoon,  it  crawls  to  some  convenient 
spot  in  a  corner,  or  under  a  piece  of  old  lumber,  usually  in  a  more 
or  less  protected  position,  but  never  so  that  the  moth  would  be  ham- 
pered when  hatching.  When  it  reaches  its  final  destination,  from 
which  the  cocoon  is  to  be  spun,  the  larva  becomes  absolutely  motion- 
less, remaining  so  for  many  hours.  This  condition  probably  has 
something  to  do  with  the  formation  of  the  silk  in  the  creature's  glands. 
No  doubt  it  is  necessary  for  a  certain  period  to  elapse  before  the 
silk  will  flow  freely  enough  to  be  spun  into  a  cocoon. 

When  this  period  is  over,  the  larva  will  suddenly  be  seen  to  stretch 
its  head  out  as  far  as  it  can  reach,  then  touching  the  object  with 
which  it  comes  in  contact,  it  fastens  the  pure  silvery  silk  to  it.  Now 
the  insect  turns  its  entire  body  with  the  exception  of  its  last  segment. 
Then,  throwing  its  head  back  over  the  body,  it  pulls  a  thin  silken 
thread  from  its  mouth,  fastening  it  again  to  the  farthest  point  that 
can  be  reached  at  the  back.  This  operation  is  repeated  hundreds  of 
times,  in  every  direction,  until  at  length  the  larva  has  completely  cov- 
ered itself.  A  second  cocoon,  much  smaller  than  the  first  and  more 
compactly  constructed,  is  then  spun  within  the  first.  The  silk  leaves 
the  insect's  mouth  in  a  silvery  liquid,  hardening  only  when  it  comes 
in  contact  with  the  air.  This  turns  to  a  deep  reddish-brown  about 
five  days  after  the  cocoon  has  been  completed. 

Inside  the  cocoon,  the  larva  shrinks  to  about  one-third  its  normal 
size.  Then  the  skin  begins  to  dry  and  becomes  very  brittle,  finally 
splitting  down  the  back  and  thus  changing  the  larva  to  a  pupa,  or 


146  INSECT  BEHAVIOR 

chrysalis,  as  this  stage  is  commonly  called.  On  the  surface  of  the 
pupa,  the  wings  and  feelers,  legs  and  eyes  of  the  future  moth  are 
plainly  visible  through  its  reddish  skin.  In  this  form,  the  cecropia 
lies  dormant  for  thirty-nine  weeks  in  its  silken  tomb. 

Then  comes  a  day  when  the  hot  sun  of  summer  strikes  the  cocoon. 
Within,  the  pupal  skin  splits  open  and  the  silk  of  the  cocoon  parts 
at  one  end.  Its  creator  has  excreted  a  few  drops  of  fluid  which  dis- 
solve the  strands  and  thus  liberate  the  insect.  A  glorious  deep  red 
and  grey  moth  with  feathery  feelers  and  great  clear  eyes  pushes 
itself  to  the  light  of  day.  Then,  clinging  to  the  edge  of  its  weather- 
worn cocoon,  this  wonderful  insect  creation  prepares  itself  for  the 
world. 

It  stretches  and  expands  its  wings ;  waves  them  gently  to  and  fro 
in  the  welcome  sun,  until  the  moisture  of  birth  has  disappeared. 
Then  it  rests  for  a  time  until  the  sun  sets,  a  great  glowing  ball  of 
crimson.  When  night  falls  over  the  land  and  the  fireflies  are  once 
more  upon  the  wing,  the  moth  answers  the  strange  mating  call 
within.  It  flies  away  through  the  perfumed  foliage  of  the  first 
sultry  night  of  summer. 


CHAPTER  XIX 
NATURE'S  WAY  WITH  UNDESIRABLES 

WEIRD   and   imperative  upon   the   hazy  early  morning 
air    floats    the    ephemeral    perfume    of    the    blooming 
squash   plants.     Yonder  in   the  garden   a   long  narrow 
line  of  them  stretches  out,  from  one  end  of  the  dew- 
drenched  field  to  the  other,  their  great  yellow  blossoms  standing  out 
in  bold  relief  against  the  deep,  rich  green  of  their  foliage.    Weak 
indeed  is  that  weird  fragrance,  from  a  human  point  of  view,  yet  it  is 
strong  enough  to  bring  the  flowers  insect  admirers,  the  beetle  and 
the  bee,  from  far  and  near  to  their  gaping  yellow  throats. 

Simple  enough  to  be  sure,  and  as  commonplace  as  any  other  cluster 
of  color  words,  yet  in  that  little  paragraph  about  the  squash,  the 
beetle  and  bee,  there  lies  a  story,  which  is  one  of  Nature's  best. 

A  black,  shiny  beetle  darted  through  the  air,  first  this  way  then 
that,  a  carefree  fortunate  creature  indeed,  too  simple  to  understand 
such  a  thing  as  care  or  worry.  Once  or  twice  it  circled  above  the 
garden  greenery,  its  filmy  wings  glistening  in  the  sunlight.  Then 
suddenly,  as  though  pulled  by  an  invisible  cord,  it  wheeled  sharply 
and  flew  straight  into  the  mouth  of  a  gaping  yellow  blossom.  The 
insect  had  felt  the  call  of  that  oddly  scented  perfume  and  it  had 
proved  irresistible. 

Eagerly  the  beetle  scrambled  down  the  big  yellow  pistil  to  satisfy 
its  thrust  for  the  sweets  which  surely  existed  in  the  flower's  hidden 
depths.  But  there  was  a  rude  surprise  in  store  for  him,  for  when 
he  reached  the  bottom  of  the  blossom  the  sweets  were  nowhere  to 

be  found.     Search  as  the  beetle  might,  there  was  nothing  there,  yet 

147 


148  INSECT  BEHAVIOR 

there  was  the  odor,  powerful  and  appetizing,  unmistakably  from  a 
delicious  nectarine  fluid.  Baffled  and  undoubtedly  angry  at  being 
thus  fooled,  the  insect  turned  and  retreated  in  panicky  haste  to  the 
outer  air  and  a  world  of  things  more  friendly. 

Now,  shortly  after  this  incident,  there  came  a  honey-bee  to  the 
blossom,  attracted  by  that  same  curious  fragrance,  or  perhaps  by 
the  brilliant  yellow  coloring  of  the  flower's  petals.  Down  the  pistil 
went  the  bee,  as  eagerly  as  the  beetle  had  done  but  a  minute  before, 
until  it  reached  the  bottom  of  the  flower.  Then  it  quivered  its  wings 
and  body  nervously,  as  though  something  were  absent  that  should 
have  been  there,  but  soon  it  settled  down',  contented  and  motion- 
less, drinking  in  the  delicious  saccharine,  from  the  flower's  hidden 
storehouse.  What  a  contrast  to  the  excited  clumsy  beetle,  who,  just 
as  Nature  intended,  would  never  taste  those  sweets  or  know  the 
secret  of  their  seclusion! 

But  why  this  apparent  favoritism  of  Nature  for  the  bee?  Why 
should  not  the  beetle  also  sip  the  honey?  It  is  not  favoritism.  Such 
a  thing  does  not  exist  in  Nature.  It  is  simply  her  method  of  pro- 
tecting the  flower  from  undesirable  visitors  and  the  beetle  is  one  of 
these,  as  we  shall  presently  see.  But  let  us  first  study  the  flower  for 
a  minute,  before  going  any  further,  that  we  may  understand  more 
clearly. 

Plants  are  helpless  inhabitants  of  our  world,  destined  to  spring 
from  a  seed  and  to  spend  their  life  just  where  that  seed  chanced  to 
be  dropped.  But  like  most  other  living  things,  they  must  be  fertilized 
before  they  may  produce  new  seed  that  will  grow  and  perpetuate 
their  race.  Their  pollens  must  cross  or  intermingle,  for  that  is  the 
way  plants  are  fertilized,  yet  they  cannot  move  about,  cannot  come  in 
contact,  except  by  chance,  so  Nature  is  called  upon  to  supply  the 
means. 

She  has  supplied  two  ways  for  the  plant  world.     One  the  wind, 


gs 


.  =  "3 


fl 

ft 
ji 


.~   u 

a.  t> 

r-.    S. 


O 


_0 

_= 
— 


149 

which  blows  the  pollen  from  one  flower  to  the  next,  but  the  prin- 
cipal agents  are  insects  and  it  is  to  the  bee  that  the  squash  plant 
owes  its  existence. 

At  the  bottom  of  the  pistil  within"  the  squash  blossom  there  is  a 
tiny  opening  slightly  larger  than  a  pin  hole,  the  only  entrance  to 
the  hidden  honey-cup  which  lies  below. 

Now,  if  we  were  to  examine  a  honey-bee  closely,  it  would  be  seen 
that  the  legs  of  the  insect  are  broadly  constructed  and  thickly  clothed 
in  a  growth  of  powerful  wiry  hairs,  while  a  short  study  of  the  mouth 
parts  would  reveal  a  strong  triple  tongue,  long  and  very  flexible. 

When  the  insect  crawls  down  into  the  blossom,  it  does  not  rush 
madly  about  after  the  method  of  the  beetle,  for  Nature  has  long 
since  taught  the  honey-bee  the  secret  of  finding  the  hidden  nectar. 
It  requires  but  a  second  or  two  to  locate  the  tiny  door  through  which 
it  plunges  its  long  tongue  into  the  pure  sweet  honey.  Meanwhile  the 
insect's  motions  have  shaken  the  pollen  from  its  fastenings  above. 
Down  it  comes  in  a  yellow  shower  about  the  drinking  bee.  Some 
of  it  sifts  in  among  the  hairs  upon  the  insect's  thighs  and  here  it 
clings  until  the  next  blossom  is  visited.  Now  some  of  it  is  bound  to 
be  brushed  off  each  time  the  busy  bee  crawls  within  a  blossom.  Thus 
the  pollens  are  blended  and  the  flowers  fertilized.  In  short,  it  is  a 
fair  exchange  between  two  different  kingdoms ;  the  bee  makes  possible 
the  offspring  of  the  plant  and  the  plant  gives  the  honey  for  the  off- 
spring of  the  bee! 

And  now  let  us  turn  to  the  poor  beetle,  who  alas  cannot  partake 
of  the  flower's  store  of  nectar,  try  as  it  might.  Unlike  the  honey- 
bee the  beetle's  legs  are  hard  and  shiny  and  bear  no  fuzzy  hairs  to 
which  the  pollen  might  stick.  He  is  useless  to  the  flower  and  there- 
fore unwelcome.  Yet  were  it  not  for  Mother  Nature,  \vith  her  de- 
vices for  protection,  the  beetle  might  drain  the  honey  from  the  flower, 


150  INSECT  BEHAVIOR 

fly  away  without  a  speck  of  pollen  clinging  to  its  legs,  and  thus  ac- 
complish nothing,  save  the  downfall  of  the  flower. 

But  the  beetle  has  a  short  tongue  indeed,  as  compared  with  that 
of  the  bee,  and  plunge  it  as  he  might  into  the  pin-hole  entrance  at 
the  bottom  of  the  pistil,  it  could  never  reach  the  sweets  in  the  bottom 
of  the  cup.  Thus  is  the  squash  protected  from  such  insects  which 
would  not  give  their  services  in  exchange.  He  leaves  the  flower  no 
wiser  than  he  came,  and  the  honey  lies  unspoiled  and  untasted  in 
its  cup,  to  await  the  coming  of  the  friendly  bee. 

Of  course  there  are  certain  insects,  other  than  the  many  species 
of  bees,  who  are  so  constructed  by  nature  that  they  are  able  to  obtain 
the  squash  flower's  honey,  but  even  these  are  beneficial  in  most  cases. 
There  are  the  Bombyliid  flies,  for  instance,  who  resemble  a  bumble- 
bee so  closely  that  one  unfamiliar  with  them  would  think  twice  be- 
fore doing  anything  to  arouse  their  possible  displeasure!  These  in- 
sects possess  a  long  flexible  tongue  like  that  of  a  bee,  and  although 
the  hair  is  absent  upon  the  legs,  the  body  is  so  thickly  clothed  with 
it  that  it  undoubtedly  serves  as  an  efficient  carrier  for  pollen. 

Many  tiny  crawling  creatures  of  the  insect  world,  small  enough 
to  insert  their  entire  head  or  body  into  the  nectar  cup,  would  be  seri- 
ous factors  for  the  plants  to  reckon  with,  had  not  Nature  supplied 
them  with  numbers  of  stout  hairs  and  spines  of  their  own,  over 
which  the  insects  cannot  pass.  Nothing  is  overlooked.  Nature  is 
indeed  a  watchful  mother. 

There  are  few  of  us  who  would  care  to  walk  abroad  upon  a  sum- 
mer's morn  down  in  the  garden  among  the  blooming  squash,  and 
see  and  watch  these  things  until  they  knew  the  why  and  wherefore 
of  it  all.  How  many  of  Nature's  secrets  there  are  about  us  all  the 
time,  just  like  this  little  story  of  the  squash,  the  beetle  and  the  bee, 
only  waiting  for  the  one  who  cares  enough  to  learn  them. 


These  are  not  flowers,  but  the  foamy  dwellings  of  immature  spittle  bugs 


Showing  the  growth  of  the  spittle  mass  from  foundation  to  the  completed  mass.    Life  size 


CHAPTER  XX 

SPITTLE  BUG  SPITTLE 


I 


"^HERE  are  few  country  people  who  have  not  at  one  time 
or  another  during  the  summer  months,  seen  curious,  foamy 
masses  clinging  to  the  stems  of  grass  or  leaves,  and  created 
by  the  spittle  bugs.1  Yet  how  few  have  ever  taken  the 
trouble  to  look  into  these  odd  creations  of  the  insect  world,  and  how 
much  of  interest  they  have  missed  through  their  lack  of  curiosity. 
Hidden  beneath  that  foamy  covering  of  tiny  bubbles,  lies  an  in- 
sect, insignificant  to  be  sure,  but  as  interesting  in  its  daily  life  as 
the  "Big  Bugs"  with  which  we  are  all  familiar.  Often  these  spittle 
masses  occur  by  hundreds  in  our  fields,  but  are  overlooked  because 
the  insect  knows  enough  to  build  its  habitation  where  white  clover 
blooms.  In  shape  and  color  the  foamy  masses  match  the  clover 
so  perfectly  that  a  casual  observer  does  not  notice  the  difference. 

The  spittle  bug  is,  of  course,  primarily  hatched  from  a  tiny  egg 
which  is  probably  placed  by  the  parent  some\vhere  about  the  base 
of  a  stem  of  grass.  A  single  egg  is  usually  deposited  upon  each 
stem,  although  at  times  one  will  find  exceptions  to  this  rule.  Such 
cases  are  proved  by  the  occasional  presence  of  several  insects  in  a 
single  mass  of  spittle.  However,  little  or  nothing  is  really  known 
concerning  the  egg  stage  of  the  spittle  bug,  the  above  statements 
being  simply  the  writer's  own  conclusions,  drawn  after  considerable 
study  of  these  creatures. 

Our  real  intimacy  with  the  spittle  bug  commences  when,  having 
left  its  egg-shell  prison,  it  comes  forth  into  the  world  in  the  form 
1  Cercopidae. 


152  INSECT  BEHAVIOR 

of  a  soft-bodied,  buff-colored  insect,  whose  general  appearance  re- 
minds one  of  a  tiny  submarine. 

When  the  eggs  have  given  birth  to  their  curious  children,  the 
insects  climb  some  distance  up  the  grass  stems,  and  here  one  may 
observe  the  most  interesting  of  their  habits — the  formation  of  the 
spittle  mass  which  has  earned  for  the  insect  its  name.  When  about 
to  begin  house  building,  the  insect  ejects  a  tiny  drop  of  extremely 
sticky  liquid  upon  the  grass  stem,  into  this  mass  it  inserts  the  tail 
end  of  its  body,  which  is  fitted  with  a  specialized  apparatus  for 
blowing  bubbles.  The  apparatus  opens  slowly,  allowing  some  of 
the  sticky  fluid  to  flow  across  its  concave  surface.  Now  the  orifice 
closes  slowly,  while  a  slight  pressure  from  within  causes  a  tiny 
bubble  to  be  blown.  This  does  not  burst,  on  account  of  its  sticky 
covering,  and  as  the  process  continues,  thousands  of  these  tiny  spheres 
of  mucus  are  manufactured,  which  eventually  surround  and  com- 
pletely cover  the  insect.  The  blowing  apparatus  in  action  reminds 
me  of  a  gold  fish's  mouth,  a  continual  opening  and  closing  motion, 
but  working,  of  course,  to  an  entirely  different  end. 

Thus  the  spittle  bug  hides  itself  away,  safe  from  the  hungry  jaws 
of  its  numerous  enemies. 

It  must  be  understood  that  when  living  in  this  curious  dwelling 
the  insect  is  not  mature,  but  is  in  a  form  which  corresponds  to  a 
caterpillar  before  it  becomes  a  butterfly.  Caterpillars  feed  upon 
the  leaves  and  stems  of  various  plants  and  trees,  but  just  what  com- 
poses the  diet  of  the  spittle  bug  is  more  or  less  a  disputed  question. 
This,  and  the  reason  for  its  manufacture  of  the  sticky  froth,  are 
points  which  have  been  neglected  by  entomologists. 

It  seems  as  though  either  one  of  these  unsolved  mysteries  might 
explain  the  other.  The  froth  is  extremely  sticky  and  therefore  acts 
as  a  trap  for  many  tiny  insects.  In  the  insect  world  we  find  a  great 
many  species  which  live  upon  animal  food  when  young,  so  why 


SPITTLE  BUG  SPITTLE  153 

should  not  the  spittle  bug  be  one  of  these,  feeding  upon  the  victims 
which  it  catches  in  its  snare?  In  more  than  one  instance,  the  writer 
has  found  a  spittle  bug  in  the  center  of  its  lair,  clinging  tightly  to 
the  body  of  some  unfortunate  insect. 

In  a  large  mass  of  spittle,  one  will  occasionally  find  several  of 
the  insects  living  together  in  various  stages  of  development.  This, 
however,  is  unusual  and  in  the  great  majority  of  cases  but  a  single 
insect  inhabits  each  mass. 

Several  days  after  leaving  the  egg,  the  insect  stops  feeding  and 
remains  motionless  within  its  dwelling  of  bubbles  for  two  or  three 
days.  At  this  period  the  spittle  commences  to  dry  up,  leaving  a 
cell  about  the  spittle  bug's  body  in  which  it  undergoes  the  trans- 
formation to  a  perfect  insect.  Its  old  skin  splits  apart  and  slowly 
the  mature  creature  pushes  forth.  She  is  a  slender  winged  insect, 
longer  and  more  agile  than  the  form  from  which  she  has  just  risen. 
After  brushing  and  drying  herself  she  burrows  through  the  dried 
white  mass  and  soon  becomes  the  mother  of  a  new  generation. 

There  are  spittle  bugs  of  many  sizes,  shapes,  and  hues,  but  this 
brief  life  history  will  suffice  for  most  of  them.  Where  they  differ 
chiefly,  is  in  the  plant  upon  which  they  occur.  Some  blow  their 
houses  among  the  grass,  others  upon  the  leaf  stems  of  basswood,  and 
giant  ones  occur  upon  the  needles  of  the  long-leaved  pines. 

Wherever  one  goes  in  summer,  providing  there  be  vegetation, 
one  finds  these  strange  little  creatures  decorating  the  foliage  with 
their  sticky  shelters  of  foam. 


CHAPTER  XXI 

THE  LIFE  OF  THE  THREAD-LEGGED  BUG 

Emesa  longipes 

IT  IS  a  musical  night  in  mid-September,  the  zenith  of  the  insect 
season.    Far  in  the  void,  moist  bands  of  mist  pass  slowly  across 
the  moon,  raising  and  lowering  the  pale  glow  in  the  world 
about  us,  first  obliterating,  now  bringing  into  clearer  relief, 
shadows  that  melt  away  almost  as  we  discover  them.    Dew  is  heavy 
on  the  grass  tips.    It  sparkles  in  the  silver  light  and  adds  its  mite  to 
September's  fragrance,  for  each  month  has  its  perfume. 

Out  there  in  the  moonlit  meadows  and  woodland,  insect  events 
rush  on.  Peace  and  war  and  industry  are  heralded,  each  sound, 
however  tiny,  fraught  with  meaning.  All  are  working  to  one  end. 
This  droning  insect  music  of  summer  is  the  battle  cry  of  their  race, 
each  individual  singing  that  he  shall  survive  to  perpetuate  it. 

By  some  the  battle  is  lost,  but  over  each  loser  a  victor  shouts 
his  triumph  and  so  the  race  goes  on.  Everywhere  tiny  wings  vi- 
brate with  songs  of  life,  while  delicate  odors  emanate  from  quiver- 
ing bodies,  that  strange  mates  may  travel  through  the  labyrinth 
of  life,  at  length  to  meet  successfully!  At  our  very  doorstep  lies 
this  world  of  insects,  yet  how  little  we  understand  and  know  its  in- 
habitants. 

Now  on  this  very  September  night,  perhaps  the  strangest  of  all 
these  myriad  insects  is  preparing  to  perpetuate  her  race.  She  is 
one  that  lays  no  claim  to  fame,  for  man  has  neglected  her  family 

history  most  completely.     Unlike  the  housefly  or  mosquito,  she  is 

154 


-=. 


THE  LIFE  OF  THE  THREAD-LEGGED  BUG       155 

of  little  account  in  our  daily  affairs,  so  the  facts  of  her  curious 
home  life  have  never  been  chronicled. 

Mating  over,  and  perhaps  feeling  the  paralysis  of  age  creeping 
over  her,  tonight  she  hastens  to  her  duty. 

Among  the  weathered  rafters  of  a  shed,  or  perhaps  an  abandoned 
house,  she  deposits  her  tough  black  eggs.  They  are  cigar-shaped 
with  a  slight  flaring  lip  at  one  end  and  deeply  fluted  like  a  Corin- 
thian column.  One  by  one  they  are  attached  to  the  roughened 
surface  of  the  wood.  Sometimes  but  an  hour,  at  others  an  entire 
day  elapses  between  the  laying  of  each,  thus  they  rarely  appear  in 
clusters.  Wherever  the  parent  wanders  from  day  to  day,  the  eggs 
will  be  found,  one  by  one  in  her  path. 

From  early  September  until  late  October,  the  process  goes  on, 
until  the  first  frosts  of  winter  claim  the  declining  creature,  leaving 
only  the  dormant  eggs  as  evidence  of  the  parent's  existence. 

She  is  a  grotesque  object  at  best,  this  mother,  slow  and  deliberate, 
with  limbs  as  delicate  as  threads  and  a  body  scarcely  more  robust. 
Yet  with  all  her  physical  shortcomings,  she  is  a  personality  in  her 
world. 

She  has  left  the  common  horde  of  insects  and  taken  up  her  abode 
with  man.  Once,  with  other  arboreal  creatures  of  the  clan  she 
lived  and  died  among  the  foliage,  but  now  she  finds  human  habita- 
tions to  her  advantage.  Doubtless,  in  ages  past,  she  was  a  dominant 
predacious  insect  of  the  air,  a  hawk  in  her  world,  dreaded  by 
others  less  spry.  Now,  in  her  new  habitat,  after  years  of  disuse,  her 
wings  are  narrow  and  degenerate,  scarcely  capable  of  easing  her  fall 
when  dropped  from  one's  hand.  Wings  have  ceased  to  be  a  ne- 
cessity, but  other  characters,  unknown  perhaps  in  other  generations, 
have  been  acquired.  Her  legs  have  grown  to  immense  length  with 
a  tiny  diameter  of  corresponding  absurdity.  The  front  pair  have 
shortened  and  developed  into  spiked  and  jointed  forceps,  while  the 


156  INSECT  BEHAVIOR 

tips  of  the  other  four  have  become  cleft  like  a  cow's,  all  as  we  shall 
see  for  a  purpose. 

The  thread-legged  bug  is  extremely  sluggish,  every  move  being 
made  very  slowly  and  with  great  deliberation.  Indeed  they  would 
make  little  progress  in  a  lifetime,  were  it  not  for  their  habit  of 
never  resting.  They  are  as  active  by  night  as  by  day  and  sleep  is 
unknown. 

In  length  the  creature's  body  measures  an  inch  and  a  half, 
while  in  width  it  is  comparable  to  a  sliver  cut  from  a  match.  Two 
of  the  three  pairs  of  legs  are  long  and  slender  and  the  third  pair, 
nearest  the  head,  resemble  a  pair  of  arms  bent  abruptly  at  the 
elbows  with  hands  bent  backward  towards  the  wrists.  Upon  these 
powerful  tongs  are  rows  of  stiff  hairs  interspersed  with  an  occa- 
sional sharp  spike,  which  serve  as  meat  hooks  for  the  insect's  vic- 
tims. 

The  head  is  very  minute,  supplied  with  red,  highly  compounded 
eyes,  which  protrude  in  a  ridiculous  fashion,  and  a  long  bayonet 
which  is  hollow  and  used  for  sucking  the  juices  from  the  creature's 
luckless  victims. 

Strange  to  say,  flies  and  small  bees  form  the  thread-leg's  chief 
article  of  diet.  One  wonders,  in  view  of  the  insect's  sluggish  nature, 
how  such  agile  objects  can  be  captured.  The  original  method,  em- 
ployed by  the  thread-legs  of  the  past  and  those  few  who  still  cling 
to  the  ancestral  home  among  the  foliage,  was  doubtless  to  remain 
motionless,  like  the  assassin  bugs,  where  flies  and  bees  abound. 
Drunk  with  the  liquor  of  newly  opened  blossoms,  they  were  easily 
fallen  upon  and  devoured. 

But  what  of  food  in  the  creature's  new  home,  among  the  weathered 
timbers  of  its  man-made  dwellings?  It  is  there  to  be  sure,  flies,  and 
even  tiny  bees,  searching  for  tunnels  wherein  to  rear  their  progeny. 
In  quality  and  quantity  the  supply  is  all  that  can  be  desired,  but  how 


A  stampede  of  thread-legged  bugs,  racing  slowly  through  a  spider's  web  towards  an  entangled  victim.    Twice 

life  size 


Greatly  enlarged  head  of  the  thread-legged  bug  showing  sucking  apparatus.    The  two  threads  protruding  from 

the  creature's  nose  are  its  feelers  or  antennae 


A  characteristic  attitude  of  the  thread-legged  bug  when  at  rest,  is  with  head  down  and  front  legs  or  tongs  stretched 

Straight  out  in  front.    Twice  life  size 


A  thread-legged  bug  casting  its  skin  just  before  becoming  mature.    Hanging  head  down,  the  insect  draws  itself 
out  of  the  old  covering.    Note  the  eye,  and  degenerate  wings.    Enlarged  twice 


THE  LIFE  OF  THE  THREAD-LEGGED  BUG       157 

to  capture  it?    To  us  the  problem  would  appear  difficult.    Not  so  to 
the  insect. 

Among  the  old  beams  and  timbers,  spiders  have  built  their  webs 
for  generations.  They  have  lived  and  died  and  abandoned  their 
silken  snares  to  whatever  purpose  they  might  serve.  At  first  they 
grew  heavy,  grey  with  the  dust  of  disuse.  They  served  no  second 
purpose  and  eventually  collapsed. 

That  was  long  in  the  pastx  long  before  the  thread-leg,  abandoning 
its  home  in  the  foliage  for  an  easier  mode  of  existence,  crept  into 
the  shelters  of  man. 

Perhaps  that  first  man-shelter,  reached  by  the  thread-leg,  was  as 
primitive  as  the  insect  herself,  yet  here  she  doubtless  experienced  a 
cobweb  for  the  first  time  and  found  it  to  her  advantage.  Perhaps 
there  was  a  fly  entangled  in  the  snare  and  no  doubt  she  was  hungry. 
Next  day,  another  creature,  entangled,  kept  her  in  the  neighborhood 
of  the  abandoned  web.  Day  after  day  her  meals  appeared,  unbidden 
by  nectar.  As  if  by  magic,  she  had  simply  to  step  forward  and  claim 
her  prey. 

She  found  herself  peculiarly  adapted  to  living  in  the  web.  Her 
long  legs  with  cloven  claws  made  travel  easy,  while  deliberate,  slug- 
gish motions  minimized  the  danger  of  entrapping  herself. 

Here  at  length,  she  was  sought  by  the  male.  Here  she  mated,  spent 
her  reclining  days  and  eventually  died,  leaving  in  her  dormant  eggs 
the  seeds  of  a  new  habit,  sleeping  now,  but  one  day  to  affect  her  entire 
race! 

It  is  strange  that  the  thread-legged  bugs  should  abandon  the  world 
of  sunlight  and  blossoms  for  their  dingy  abode  among  the  spider 
webs,  yet  it  is  in  keeping  with  their  slow  and  indolent  mode  of  life. 
Perhaps  it  is  better  to  have  one's  food  brought  magically  to  hand 
than  to  work  for  it,  even  at  the  sacrifice  of  sunlight! 


158  INSECT  BEHAVIOR 

The  eggs  winter  over  in  a  dormant  state,  hatching  sometime  during 
the  spring.  A  quantity  carried  to  South  America  for  experimental 
purposes  poured  forth  their  quaint  inmates  in  the  latter  part  of 
February,  but  in  the  North,  May  is  doubtless  the  hatching  month. 

The  young  thread-legs  are  exactly  like  the  parents,  only  quite 
transparent  and  scarcely  over  a  quarter  of  an  inch  in  length.  They 
grow  quite  rapidly,  casting  off  their  old  skin,  like  a  caterpillar,  sev- 
eral times  before  they  become  full  grown,  in  August.  At  this  time, 
shortly  before  paring  commences,  I  have  witnessed  what  I  called 
"Stampedes."  The  insects  congregate  in  hundreds  about  certain 
webs,  which  seem  to  be  more  popular  than  others.  All  goes  well 
for  a  time,  the  individuals  fraternizing  with  one  another  peacefully 
enough  until  some  unfortunate  creature  from  the  outer  world  chances 
to  drop  into  this  snare. 

The  instant  a  victim  becomes  entangled,  a  most  ridiculous  stampede 
follows  to  see  who  will  first  reach  and  bear  off  the  juicy  morsel. 
The  absurdity  of  this  event  is  increased  by  the  fact  that  the  would- 
be  stampeders  cannot  possibly  move  rapidly.  The  sight  reminds  me 
of  that  nightmare  wherein  I  am  in  dire  need  of  running,  yet  try  as  I 
may,  I  can  move  no  faster  than  a  snail. 

When  feeding,  the  creature  holds  its  prey  in  the  bend  of  its  spiked 
forelegs  at  a  safe  distance  from  its  head  and  body.  Its  sharp  sucking 
tube  is  then  thrust  into  the  captive,  whose  life  is  rapidly  drawn  into 
the  body  of  the  thread-leg. 

Flies,  bugs  and  even  bees  hold  no  terror  for  this  insect,  who  is 
immune  from  their  bites  and  stings.  From  their  position  in  the 
creature's  outstretched  arms  they  can  reach  no  vital  spots.  A  wildly 
darting  sting,  a  poisoned  fang  or  a  tireless  set  of  muscles  are  of  no 
avail,  and  the  thread-leg  feeds  at  leisure. 

Thus  these  strange  creatures  live  their  easy,  toilless  lives.     They 


C"O 

•&§, 

>"c 


-o  . 

a  <* 

«  S 

i  C 


•5 -a 

.5  « 


THE  LIFE  OF  THE  THREAD-LEGGED  BUG       159 

have  no  enemies  that  I  can  discover,  no  work,  no  worries,  and  they 
require  no  sleep.  From  the  hour  of  birth  to  the  hour  of  death  they 
idle-  away  their  time.  Eating  is  their  sole  occupation,  yet  they  re- 
main one  of  the  leanest  creatures  on  earth! 


CHAPTER  XXII 

TRAILING  A  BEE  TO  ITS  LAIR 

A  TINY  solitary  bee,1  with  a  yellow  speck  on  each  of  her 
hind  legs,  winged  her  way  to  the  sandy  driveway,  then 
after  hovering  for  a  second  or  two  above  a  little  hill  of  sand 
and  pebbles,  she  dove  straight  as  an  arrow,  into  the  hole  in 
the  center  of  the  mound. 

Near  by  there  was  another  creature,  a  huge  two-legged  one,  thou- 
sands of  times  the  size  of  the  bee,  but  that  little  insect  excited  the 
big  animal  greatly,  so  much  so  in  fact,  that  he  could  not  rest  until 
he  had  seen  the  inside  of  the  little  creature's  nest  and  found  out  the 
why  and  wherefore  of  her  each  and  every  fiercely  energetic  move. 

But  there  was  only  difficulty  and  disappointment  in  store  for  the 
big  creature,  for  in  his  haste  to  get  at  the  secret,  he  tried  to  dig 
out  the  bee's  home  in  the  underworld  and  after  following  its  curious 
winding  course  for  a  few  inches,  the  sand  and  pebbles  rolled  into 
the  opening,  buried  the  unsuspecting  insect  and  ended  the  matter, 
as  far  as  that  particular  bee  and  her  nest  were  concerned! 

Some  days  later,  however,  another  little  mound  much  like  the 
first  one,  only  higher,  appeared  upon  the  drive  close  to  the  old  site. 
Now  it  happened  that  the  big  interested  creature  also  spied  this 
second  little  heap  of  sand  and  stones.  The  sight  made  him  rejoice, 
but  he  resolved  to  be  more  cautious,  lest  he  destroy  another  home 
before  finding  out  the  mysteries  going  on  within. 

All  that  day  and  all  of  the  next  that  little  bee  was  watched,  and 
each  time  that  she  came  to  the  nest,  her  thighs  were  clustered  with 

1  Colletes. 

1 60 


' 


The  tiny  solitary  bee  resting  between   polen-laden 
journeys.    Life  size 


Making  a  plaster  cast  of  the  bee's  burrow 


Entrance  to  the  bee's  tunnel  showing  general  surroundings.     Somewhat  reduced 


TRAILING  A  BEE  TO  ITS  LAIR  161 

yellow  dust  and  each  time  she  left  the  mound,  that  yellow  dust 
was  gone. 

Here  then  was  the  first  mystery,  one  which  might  be  cleared  be- 
fore the  nest  was  even  touched,  and  one  which  was  sure  to  prove 
interesting.  When  the  little  insect  returned,  for  perhaps  the  fiftieth 
time  that  day,  she  was  rudely  surprised  to  find  herself  fast  in  the 
folds  of  a  net  which  would  not  yield,  instead  of  in  the  darkness  of 
her  tunnel.  But  she  wras  not  to  be  injured.  Her  only  loss  were 
those  two  yellow  masses  upon  her  legs  and  then  she  was  free  once 
more. 

The  yellow  masses  proved  to  be  pollen,  the  seed  germs  of  flowers, 
that  yellow  powder  which  one  is  sometimes  dusted  with  upon  brush- 
ing against  a  blossom.  Even  more  interesting  was  the  fact  that  the 
pollen  was  that  of  the  goldenrod,  and  no  goldenrod  could  be  found 
within  a  quarter  of  a  mile  of  the  nest!  Thus  each  time  the  insect 
returned  with  her  burden  of  yellow  dust,  she  had  traveled  half  a 
mile. 

But  why  does  she  take  that  pollen  from  the  light  of  day  and  carry 
it  far  below  the  ground,  leave  it  and  then  hurry  off  in  search  of 
more?  Let  us  follow  her  into  the  nest  and  see. 

When  the  little  bee  leaves  the  sunlight  she  does  not  go  straight 
down,  but  follows  a  curious  twisting  tunnel,  pitch  black,  and  just 
large  enough  to  fit  her  body.  Maybe  she  would  rather  have 
it  straight,  but  there  are  projecting  roots,  stones  and  many  other  ob- 
jects too  large  for  her  to  move,  and  even  a  bee  cannot  foresee  these 
obstacles.  She  must,  therefore,  dig  around  them,  hence  the  shape 
of  the  burrow,  which  is  seldom  twice  the  same. 

At  the  end  of  this  subterranean  passage  is  an  earthen  cell,  elon- 
gated and  slightly  larger  in  diameter  than  the  rest.  On  reaching 
this  little  storehouse,  for  such  it  is,  she  removes  the  pollen  from 
her  thighs  by  means  of  her  other  four  lees.  Then  she  mixes  the 


i6a  INSECT  BEHAVIOR 

yellow  substance  with  clear  sweet  nectar,  kneads  it  into  a  honey- 
paste  and  tamps  it  down  upon  the  previous  layers  within  the  cell. 

What  energy  that  little  creature  has  to  first  dig  that  burrow,  sixty 
times  her  own  length,  into  the  solid  ground,  then  to  fill  the  cell  with 
pollen,  which  means  hundreds  of  loads  to  be  carried,  kneaded  and 
tamped  into  place.  And  even  now  she  is  not  through,  for  there  are 
eggs  to  be  laid  and  perhaps  other  nests  to  be  made  and  looked  out 
for. 

The  egg  is  laid  upon  the  honey-paste  within  the  cell  and  after  this 
the  mother  is  through  with  that  particular  nest,  for  it  is  now  sealed 
and  deserted.  Within,  the  young  bee,  a  white  legless  creature, 
hatches  and  feasts  upon  the  generous  store  of  sweetened  pollen  which 
the  mother  has  supplied.  How  long  it  feeds,  someone  else  must  say, 
but  soon  it  transforms  into  a  chrysalis,  lies  motionless  for  some  weeks, 
perhaps  months,  then  pushes  its  way  through  the  earth  to  the  world 
of  sunlight,  a  perfect  insect. 

If  it  be  a  male,  it  mates  and  lives  a  life  of  ease,  if  a  female,  it  has 
work  to  do,  hard  work  and  plenty  of  it,  before  an  enemy  or  Jack 
Frost  puts  an  end  to  its  brief  existence  in  our  world. 

How  did  the  man  find  out  all  this?  By  watching,  constantly  and 
patiently,  not  by  guessing.  Nor  was  it  tedious,  uninteresting  work; 
far  from  it,  the  big  two-legged  creature  was  sorry  when  the  work 
was  finished  and  the  little  bee  had  flown  to  pastures  new. 

But  how  did  he  know  what  that  tiny  subterranean  passage  was  like, 
why  did  not  the  sand  and  pebbles  fall  into  this  one  when  it  came  time 
to  explore  its  depths?  New  methods  were  used  and  caution 
triumphed,  that  is  why. 

When  the  bee  had  finished  her  work  about  the  nest,  she  was  not 
allowed  to  seal  it.  Instead  it  was  filled  with  liquid  plaster  of  paris, 
which  ran  down  inside,  filling  every  little  nook  and  corner  of  the 
tunnel.  Several  hours  later  it  had  hardened  like  rock,  and  the  man, 


Model  ot  the  bee's  nest  made  from  a  plaster  cast.    One-third  natural  size 


Interior  of  the  bee's  burrow  showing  cell  filled  with  honey  paste.    From  the  model.    Twice  life  size 


Excavating  the  plaster  cast  of  the  burrow.    Photograph  one-third  natural  size 


TRAILING  A  BEE  TO  ITS  LAIR  163 

with  boyish  enthusiasm  and  excitement,  sat  down  upon  the  ground 
and  very  carefully  chiseled  the  earth  away.  Every  minute  revealed 
a  new  twist  or  turn  and  every  minute  the  excitement  grew,  as  with 
an  excavator  of  Pompeii,  until  the  end  was  reached  and  the  pollen 
found. 

Then  the  perfect  cast  was  laid  upon  a  smooth  pine  board  and  its 
course  traced  upon  the  wood  in  pencil.  With  the  aid  of  a  gouge  and 
a  sharp  knife,  a  duplicate  of  the  original  nest  was  modeled  in  the 
wood,  showing  every  turn  and  every  indentation  just  as  the  insect 
had  made  them.  Then  the  board  was  brushed  with  glue  and 
sprinkled  with  fine  sifted  sand,  taken  from  the  spot  where  the  nest 
actually  existed.  To  represent  the  pollen,  a  touch  of  powdered  yel- 
low felt  was  glued  within  the  artificial  cell,  and  it  was  finished  a 
perfect  model  of  the  little  creature's  home. 

Then  it  was  photographed  as  an  everlasting  monument  to  the  skill 
and  energy  of  the  tiny  insect  who  designed  it. 


CHAPTER  XXIII 

CAMOUFLAGED  INSECTS 

BY   Nature    the   art   of    camouflage    has    long   been    prac- 
ticed.   It  is  her  way  of  affording  protection  to  those  of  her 
defenceless  children  who  might  otherwise  fall  victims  to 
predacious  enemies.     To  us  the  word   is   a  war-baby,  com- 
ing from  the  battlefields  of  France.     It  has  since  been  applied  to 
an  endless  variety  of  things;  most  anything,  which  by  nature  of 
peculiarly  applied  patterns,  is  made  to  blend  with  its  surroundings, 
and  thus  appear  more  or  less  obscure  to  the  eye. 

Among  insects  camouflage  has  been  carried  beyond  mere  arrange- 
ment of  color,  pattern.  We  find  creatures  whose  general  outline  as 
well  as  pigmentation  mimics  their  natural  surroundings  to  such  a 
marked  degree  that  it  is  often  difficult  to  distinguish  where  habitat 
leaves  off  and  where  inhabiter  begins. 

This  curious  state  of  affairs  has  been  developed  through  thousands 
of  years  by  the  process  of  selection.  Individuals  vary  greatly  in  color 
and  those  fortunate  ones  matching  their  surroundings  .more  closely, 
naturally  survived  longer  than  their  less  protectively  patterned 
brothers.  Thus,  as  time  went  on,  the  pattern  of  these  selected  in- 
dividuals became  dominant  of  the  species,  developed  in  some  cases 
to  a  phenomenal  degree. 

A  remarkable  case  of  this  kind  is  shown  in  Figure  109,  of  a  cater- 
pillar or  larva  which  later  transforms  into  a  geometrid  moth.  In 
the  larval  state  the  insect  bears  a  very  close  resemblance  to  a  twig. 
Its  habit  of  clinging  to  a  real  twig  with  its  posterior  "legs"  and 

allowing  the  body  to  swing  out,  adds  to  the  illusion.    The  head  of 

164 


Caterpillar  of  a  geometrid  moth  which  resembles  the  twigs  of  the  insect's  food  plant,  thus  gaining  immunity 

from  the  attacks  of  its  enemies.    Twice  life  size 


This  remarkable  caterpillar  resembles  the  excretia  of  a  bird  so  closely  that  only  one  accustomed  to  seeing  it  under 
all  conditions,  realizes  that  it  is  a  living  creature.    Greatly  enlarged 


CAMOUFLAGED  INSECTS  165 

the  caterpillar  resembles  a  leaf  bud,  while  in  color  the  entire  creature 
is  an  exact  counterpart  of  a  rough  apple  twig,  the  plant  upon  which 
it  naturally  feeds.  Thus  complete  immunity  is  secured  from  the  at- 
tacks of  birds  and  all  enemies  which  depend  chiefly  upon  sight. 

A  similar  case  is  that  of  the  slug  caterpillar,  Figure  no,  of  the 
family  Cochlidiidae.  Its  general  color  is  leaf-green  with  some  small 
amount  of  dark  red  near  the  head,  which  is  pointing  downward  in 
the  photograph.  On  the  whole,  to  the  casual  observer,  it  is  scarcely 
distinguishable  from  a  swollen  bud.  Even  more  remarkable  are  the 
caterpillars  which  rely  for  their  protection  upon  their  mimicry  of 
the  excreta  of  birds,  Figure  in.  I  have  been  completely  fooled  by 
these  larvae  on  more  than  one  occasion.  They  frequently  rest  in  the 
center  of  a  green  leaf  and  while  conspicuous,  never  suggest  a  living 
insect  to  the  uninitiated.  In  color,  the  upper  and  lower  portions  of 
the  body  are  dark  chocolate  brown,  banded  through  the  center  with 
pure  white,  which  suggests  the  lime  so  often  seen  in  the  excreta  of 
birds.  The  entire  creature  is  highly  glossed,  which  gives  a  fresh 
and  moist  appearance  to  the  object,  which  makes  no  attempt  to  con- 
ceal itself,  depending  entirely  upon  its  strangely  camouflaged  body 
for  protection! 

In  the  course  of  my  field  activities,  I  have  run  across  a  great  num- 
ber of  cases  \vhere  insects  were  curiously  camouflaged  to  their  sur- 
roundings. They  are  far  too  numerous  to  describe  here  in  detail, 
but  one  or  two  are  of  particular  interest. 

In  British  Guiana,  inhabiting  the  trails  through  the  virgin  forest, 
is  a  tiny  species  of  thecla,  a  bright  blue,  angular-winged  butterfly. 
Upon  endeavoring  to  capture  one  or  two  specimens,  I  swooped  with 
my  net  in  the  ordinary  way,  where  several  individuals  \vere  flying 
about  chasing  one  another,  but  as  I  did  so  all  of  them  disappeared 
as  if  by  magic.  In  a  few  minutes  they  returned,  one  by  one,  appar- 
ently from  the  vegetation  directly  before  my  eyes.  A  second  and 


1 66  INSECT  BEHAVIOR 

third  swing  of  my  net  produced  the  same  results.  Try  as  I  might, 
between  swoops,  I  could  find  no  trace  of  my  quarry  until  they  re- 
turned to  the  trail  of  their  own  accord,  yet  they  never  appeared  to 
go  far  away. 

At  length  I  decided  to  beat  the  surrounding  vegetation,  and  upon 
doing  so  caught  two  of  the  butterflies.  Examination  revealed  that 
the  under  side  of  the  wings  were  bright  green,  which  matched  per- 
fectly with  the  jungle  leaves.  I  stunned  one  and  placed  it  upon  a 
leafy  twig  and  turned  away.  In  a  minute  I  looked  back  and  found 
the  insect  with  great  difficulty,  so  perfectly  did  it  blend  with  its  sur- 
roundings. When  I  swung  my  net,  the  insects  had  retreated  to  the 
foliage  and  although  bright  blue  in  flight,  they  instantly  disappeared 
upon  folding  their  wings  when  coming  to  rest  among  the  leaves. 

In  the  Andean  jungle  of  Colombia,  one  finds  strange  transparent 
butterflies.  Unlike  our  familiar  species,  they  possess  no  scales  and 
are  therefore  without  color  patterns.  The  wings  are  the  color  of 
clouded  glass,  but  quite  transparent.  In  flight  they  are  easily  seen, 
but  upon  coming  to  rest  among  the  brown  leaves  which  cover  the 
forest  floor,  they  become  more  or  less  invisible  and  are  thus  pro- 
tected. 

Placed  upon  a  printed  page,  one  may  read  through  their  wings  as 
readily  as  through  a  piece  of  glass,  only  the  body  and  veins  of  the 
insect  being  too  dense  for  this  purpose. 

I  once  found  a  drinking  place  of  these  butterflies  in  Colombia.  A 
huge  moss-grown  boulder,  upon  which  a  tiny  stream  of  water  con- 
tinually fell,  produced  a  popular  saloon  to  which  hundreds  of  these 
skeleton  insects  resorted.  It  was  an  interesting  sight  to  see  them 
gathered  together  in  such  numbers  to  the  exclusion  of  other  species. 
From  a  distance  only  their  brown  bodies  and  wing  veins  were  visi- 
ble, resembling  a  multitude  of  stick  insects,  clustered  upon  the  water- 
soaked  moss. 


CAMOUFLAGED  INSECTS  167 

In  a  great  many  cases  insects  are  not  camouflaged  as  we  understand 
the  word.  Many  are  bright  and  gaudy  and  attract  rather  than  de- 
ceive the  eye.  In  such  cases,  these  bright  spots,  bands,  spines  and 
ground  colors  serve  as  warning  signals  to  the  enemies  of  the  insects. 
They  are  protective  measures  of  another  variety  employed  by  Nature 
for  a  double  purpose.  They  are  to  protect  the  bearer  against  its 
enemies  and  at  the  same  time  the  would-be  sampler  of  insects  in 
general. 

Bright  and  gaudy  colors  are  often  a  sign  of  poisonous  qualities  in 
an  insect,  or  one  whose  blood  lymph  or  other  body  fluids  possess  a 
disagreeable  taste.  In  the  light  of  the  above  statement  it  is  inter- 
esting that  many  harmless  and  edible  insects  mimic  in  pattern  those 
species  who  are  really  ill  tasting  or  poisonous.  Thus  the  great 
monarch  butterfly  is  closely  mimicked  in  color  by  another  species. 

The  monarch  (Anosia  plexippus)  is  one  of  the  most  successful  of 
insects.  It  is  abundant  and  widely  distributed,  due  in  all  probability 
to  qualities  that  make  it  distasteful  to  birds  and  other  enemies,  in  all 
stages  of  its  life.  Thus  it  has  become  a  dominant  species  in  the  insect 
world. 

To  mimic  such  a  species  would  be  at  once  advantageous  to  other 
insects  and,  strangely  enough,  the  viceroy  butterfly  (Basilarchia 
archippus)  gains  immunity  from  attack  in  this  way,  even  though  it 
is  in  all  probability  an  edible  species. 

In  South  America  I  found  a  species  of  Heliconidae,  a  medium- 
sized  glossy  black  butterfly  bearing  rose-colored  bands  across  the 
wings.  This  species,  except  in  the  contour  of  its  wings,  was  closely 
mimicked  by  a  species  of  Papilionidae,  inhabiting  the  same  general 
locality.  The  former  are  supposed  to  be  inedible  or  distasteful. 
Endless  cases  might  be  cited,  like  the  above,  especially  among 
tropical  insects,  who  are  camouflaged,  so  to  speak,  to  resemble  some- 


168  INSECT  BEHAVIOR 

thing  which  is  dangerous  and  to  be  left  alone  by  birds,  lizards  and 
other  enemies  of  the  insects. 

There  is  still  another  type  of  camouflage  among  insects  worthy  of 
mention,  one  which  is  doubtless  effective  in  protecting  absolutely 
harmless  and  passive  creatures  from  being  attacked  and  eaten. 

We  find,  for  instance,  the  chrysalis  of  a  butterfly,  a  species  of 
Vanessa.  It  hangs  by  a  tiny  silk-fastened  stem  under  a  protecting 
fence  rail.  Within  the  shell  of  the  chrysalis,  there  is  nothing  but  a 
mass  of  disintegrating  tissues,  a  thick  fluid,  studded  with  globules  of 
fat.  It  is  neither  caterpillar  nor  butterfly.  It  cannot  thrash  about 
from  side  to  side  or  make  a  demonstration,  there  are  no  spines  to 
pierce  a  would-be  enemy,  no  wings  by  which  the  creature  might 
take  flight.  It  is  as  helpless  now  as  so  much  custard,  for  the  insect 
is  in  the  process  of  change  from  one  form  to  another. 

Such  is  the  actual  condition  of  the  pupal  butterfly,  but  let  us 
examine  its  outer  covering.  It  is  a  frightful-looking  object, 
armored,  and  covered  with  sharp  spikes  between  which  beady  false 
eyes  peer  out.  It  is  absolutely  harmless  but  appears  otherwise.  To 
birds  it  is  doubtless  a  thing  to  beware  of,  yet  one  tiny  puncture  of  its 
brittle  covering  would  reveal  a  delicious  feast  within! 

Many  insects  are  thus  protected,  ones  that  could  not  compete  in 
any  form  of  battle.  They  are  given  immunity  from  attack  because 
they  could  not  ward  it  off  themselves.  In  the  case  of  the  trans- 
forming pupa,  some  such  form  of  protection  becomes  a  necessity.  A 
butterfly  in  the  making  is  as  helpless  as  the  egg  from  which  it  sprung, 
so  Nature  resorts  to  camouflage  to  terrorize  the  destroyers  of  her 
children. 


— 
<o 

u 

'= 
g 


.5  e 
=  •» 


d 


CHAPTER  XXIV 

LIVING  EXAMPLES  OF  THE  GEOLOGICAL  PAST 

STRANGE  as  it  may  seem,  the  most  ancient  types  of  insects 
are  still  represented  alive,  in  the  world  today.  Unlike  the 
ancient  men  and  mammals  of  our  planet,  whose  scanty  his- 
tory comes  to  us  through  occasional  beds  of  fossil  remains, 
insects  provide  us,  through  those  which  live  today,  with  an  actual 
glimpse  into  the  great  geological  past. 

Some  of  the  creatures  have  undergone  little  change  during 
millions  of  years.  They  are  today  almost  what  their  ancestors  were 
in  those  past  ages,  ancestors  who  roamed  the  prehistoric  fields  and 
forests,  now  buried  deep  in  the  crust  of  the  earth. 

That  these  insects  still  exist,  almost  unchanged,  still  primitive  in 
their  structure,  shows  that  Nature  does  not  always  do  away  with  her 
early  experiments.  She  does  not  cause  them  all  to  become  extinct 
in  favor  of  more  modern  ones. 

These  primitive  insects  which  still  inhabit  the  world,  are  known 
scientifically  as  Aptera,  an  order  which  includes  two  suborders,  the 
Thysanura  and  Collembola,  commonly  known  as  Bristle-tails  and 
Spring-tails. 

Aptera  today  are  the  most  widely  distributed  of  all  insects.  They 
are  found  in  Europe,  the  Faroe  Islands,  Chile,  Alaska,  Joseph 
Land,  the  Sandwich  Islands,  the  South  Orkneys,  Graham  Land,  the 
United  States,  and  South  Victoria  Land.  Some  have  been  collected 
from  the  snows  of  frozen  mountain  tops  while  others  are  found  at 
sea-level,  or  below,  in  caves  and  caverns  in  the  hottest  climates. 

They  are  very  delicate,  often  minute,  soft-bodied  insects,  covered 

169 


170  INSECT  BEHAVIOR 

in  some  cases  with  microscopic  lavender  scales  like  those  of  a  fish. 
Those  belonging  to  the  Thysanura  possess  strange  forked  appendages 
which  protrude  like  long  tails  from  the  posterior  segments  of  the 
body.  These  are  in  addition  to  the  legs,  and  antennae  or  feelers,  and 
their  purpose  is  not  definitely  known. 

In  Collembola  the  species  are  supplied  with  a  catch,  and  spring, 
which  upon  release,  hurls  the  creature  bodily  and  automatically  out 
of  harm's  way.  They  are  also  supplied  with  paired  sacs,  which  are 
carried  upon  the  ventral  tube  of  the  first  of  the  six  body  segments. 
These  assist  the  creature  when  walking  upon  very  smooth  surfaces 
and  doubtless  serve  as  breathing  organs  in  addition. 

As  it  is  extremely  unlikely  that  such  delicate  insects  could  be 
transported  across  seas  and  oceans,  their  remarkable  geographical 
range,  so  wide  and  discontinuous,  suggests  their  great  antiquity. 
Doubtless  in  ages  past,  before  our  planet  was  in  the  process  of  change 
towards  what  it  is  today,  there  were  no  seas  or  channels  separating 
the  various  countries  included  in  the  range  of  the  Aptera.  The 
United  States  and  Europe,  together  with  Chile  and  the  more 
isolated  islands,  were  probably  one  continuous  continent.  If  not,' 
why  then  should  we  find  these  identical  little  insects  in  each  of  those 
places  today?  That  they  are  of  very  ancient  origin  is  undoubted. 
It  is  what  makes  the  Aptera  so  important  and  interesting  to  scientists 
today. 

Geologists  have  found  many  fossil  remains  of  these  insects  in  very 
ancient  strata  of  the  earth's  crust.  A  supposed  specimen  was 
unearthed  from  the  Silurian  deposits  of  New  Brunswick,  buried 
there  during  a  comparatively  quiescent  period  in  the  earth's  history. 
At  this  time  a  great  sinking  of  the  land  was  followed  by  a  relative 
rising,  which  affected  wide  areas  in  the  northern  hemisphere.  Other 
remains  found  in  Carboniferous  deposits  in  France  were  of  Aptera 
which  lived  in  prehistoric  forests  of  great  exuberance,  before  they 


Once,  with  other  arboreal  creatures  of  the  clan,  the  thread-legged  bug  lived  and  died  among  the  foliage.    Twice 

life  size 


Poison  spines  on  the  lo  caterpillar 

This  catterpillar,  which  later  transforms  into  the  lo  moth,  is  splendidly  protected  from  its  enemies  by  masses  of 

spines,  each  bearing  a  highly  poisoned  tip.    The  slightest  scratch  from  one  of  these  darts  causes  extreme  pain, 

itching  and  great  discomfort  probably  due  to  formic  acid,  a  substance  which  serves  as  a  protection  to 

manv  insects 


EXAMPLES  OF  THE  GEOLOGICAL  PAST         171 

were  buried  to  become  our  coal  seams  of  commerce.  Here  and  there 
a  few  others  have  been  found  in  older  strata  but  it  is  not  until  the 
Tertiary  that  their  remains  were  found  in  any  quantity. 

During  this  period  or  era,  the  configuration  of  the  earth  was 
steadily  approaching  that  of  the  present  day,  but  there  still  existed 
a  great  equatorial  ocean,  while  East  India  and  Africa,  Australia  and 
Asia,  North  Europe  and  America  were  probably  united  by  land  con- 
nections. The  faunas  of  the  planet  also  approached  their  present 
state,  and  might  have  continued  to  expand  more  broadly,  had  it  not 
been  for  a  rapid  lowering  of  the  earth's  temperature,  which  brought 
about  a  great  glacial  period. 

Spring-tails  of  the  present  day  live  in  moss,  under  logs  or  fallen 
leaves,  in  grass,  on  water,  snow,  or  in  almost  any  place  that  is  suf- 
ficiently damp.  Their  mouth  parts  are  hidden  and  very  difficult  to 
study,  but  the  insects  are  doubtless  vegetable  feeders  like  their 
Bristle-tail  relatives. 

Millions  of  years  ago  the  latter  probably  fed  on  water-soaked  seeds 
or  other  vegetable  matter  of  a  starchy  nature,  but  today  they  inhabit 
the  houses  of  man,  feeding  upon  the  paste  which  keeps  our  wall 
papers  in  place,  or  upon  the  same  substance,  wrhen  it  may  be  found, 
in  the  bindings  of  books  upon  our  shelves.  It  is  a  strange  habit  in- 
deed, to  acquire  upon  one's  Nth  millionth  birthday  as  a  race! 

Another  creature,  still  existing,  whose  kind  may  be  traced  like  the 
Aptera,  far  into  the  geological  past,  is  the  inappropriately  named 
wood-louse.  In  reality  a  terrestrial  crustacean  closely  related  to 
the  land  crabs  and  not  an  insect  in  any  sense  of  the  word,  this  little 
oniscus  is  familiar  to  everyone  living  in  the  country'  who  has  ever 
turned  over  a  stone  or  log  or  a  bit  of  decaying  wood. 

Members  of  the  Isopoda  are  represented  in  all  seas  and  lands,  the 
wood-louse  being  the  only  land-loving  representative  of  the  order. 


172  INSECT  BEHAVIOR 

Hundreds  of  species  are  known  in  the  world  and  they  are  perhaps 
one  of  the  commonest  creatures  occurring  in  the  United  States. 

The  female  oniscus  carries  her  eggs  in  a  pouch  which  covers  the 
under  surface  of  her  thorax.  The  young  are  exactly  like  the  adults 
except  for  the  last  pair  of  legs,  which  are  lacking,  and  these  are  not 
acquired  until  later  in  life.  The  significance  of  this  strange  fact 
would  be  hard  to  discover,  and  like  the  life  histories  of  so  many  of 
our  tiny  creatures,  lies  shrouded  in  mystery. 

It  is  strange  that  these  creatures  and  the  Aptera,  still  progressing 
in  our  world  today,  have  survived  great  upheavals  of  the  earth,  great 
changes  of  climate,  great  floods  and  glacial  periods,  and  yet  have 
come  through  unscathed  to  this  modern  century.  Where  great 
mammals,  birds  and  reptiles  of  bygone  ages  failed  and  left  us  only 
fossil  records  of  their  existence,  these  tiny  things  succeeded  and  came, 
living  into  our  day.  They  have  been  handed  down  to  us  by  Nature 
as  priceless  heirlooms  of  our  planet's  ancient  family. 


Wood  lice  or  pill  bugs.    Though  commonly  termed  bugs,  they  are  in  reality  terrestrial  crustaceans  related  to 

the  land  crabs.    Four  times  life  size 


A  thysanuran  or  bristle-tail.    A  creature  that  has  come  down  through  the  ages  to  eat  the  paste  upon  our  wall 
papers  and  book  bindings.    One  of  the  most  primitive  of  existing  insects.    Enlarged  three  times 


INDEX 


Africa,  171 
Agalenidas,    104 
Agouti,  77 
Alaska,  169 
Andean  jungle,  166 
Anosia  plexippus,  167 

Ants,  South  American  army,  118,  119,  120,  121, 
122,  123,  124 

bite  of  army,  123 

Carpenter,  no,  in,  112,  115 
battles  of,  114 

cattle  tending,  113,  114 

Leaf-cutting,    enemy   of,    115,    116 
poison  of,   1 1 6,  117 

Mound,  experiment  on,   134,  135 

Slave  making,  112 

slave-making  habit,  reflex  of,  112 
Ant  battles,  114 
Ant  birds,  124 
Ant  cows,  113,  114 
Ant  lion,  25,  105 

Ants,  109,  no,  in,  112,  113,  114,  115,  116,  117, 
118,  119,  120,  121,  122,  123,  124,  134,  135 
Aphids,  113,  114,  134 
Aptera,  169 

distribution  of,   169,    170 

fossils  of,  170 

Archippus,  Basilarchia,   167 
Asia,   171 
Asilidae,    128 
Attadae,    115 
Australia,   171 

B 

Bartica,   118 

Basilarchia    archippus,    167 
Battles,  ant,   114,   115 
Bee,  bumble,   104 

blue-flower,   87 

green-flower,  87 

honey,    148 

humble,  87 

Bees,  87,  148,  104,  1 60 
Beetle,   carabid,   147 

oil,    104,    105 

rove,  25 

Xenos,   97 

Beetles,  25,  97,  104,  105,  147 
Birds,  ant,   124 
Black  reed-wasp,  27 


Blue  huntress,  68 

Blue  mud-dauber,   138,   140 

Bristle-tails,   169 

British   Guiana,    118,   165 

Bug,   spittle,   151 

thread-legged,  life  history  of,   154 
egg  laying,   155 
food  of,  156 
stampedes  of,   158 
Bumble  bee,  parasite  of,  104 
Butterflies,   invisibility  of,  165 

transparent,    166 

Heliconidae,   167 

mimicry  of,  167 

monarch,  167 

mourning  cloak,  168 
Papilionadae,   167 

thecla,   165 

viceroy,    167 


Caddice  fly,  108 
Caddice  worm,  107 
Caeruleum,  Chalybion,  138 
Camouflaged  insects,  164 
Camponotus  pennsylvanicus,  no,   115 
Cannibal   wasps,  85 
Caterpillar,   cabbage,   99 

cecropia,   114 

cochlidiid,   165 

protective   colors  of,   145 

slug,    165 

twig,   164 

Cecropia  moth,  life  history  of,   143 
Cecropia,   Samia,    143 
Centipedes,   122 
Ceratinadae,  87 
Cercopidae,    151 
Chalybion  caeruleum,    138 
Chile,  169 

Chlorion  neotropicus,  68 
Cicada,  91,  92,   136 
Cinereohirtum,  Trypoxylon,  27 
Cochlididae,   165 
Collembola,   169 
Colletes,   160 

burrow  of,  161 

burrow,   method   of  molding,    162 
Colombia,    166 
Controlled  pupation,  77 
Crickets,  sight  of,   128 

tree,    125 


173 


INDEX 


Crickets,  49,  50,  120,  128 
Crustaceans,   terrestrial,    171 

D 

Daddy-long-legs,   120 
Deposits,  carboniferous,   170 

tertiary,   171 
Dialyzer,  insect,  65 
Dragonfly,   25 

sight  of,   128 
Drassidae,    104 

E 

East  India,   171 

Emesa  longipes,  154 

Epeiridae,   103 

Europe,   169 

Excretia,  of  young  wasp,  contents  of,  38 

method  of,  28,  57,  58 
Experiments,   some  insect,  134 
Exsectoides,  Formica,  112,   134 


Hornets,  98,   99 

How  the  greenbottle  does  its  duty,   129 
Howling  monkey,  77,   78 
Hydropsychidae,   107 


Insects  and  other  strategists,  102 
Insect   eye,   anatomy  of,    126 
Insects,   as   pollen  carriers,   149 

camouflaged,    164 

protective  patterns,   how  obtained,    164 

sight   of,   the,    125 

warning  signals  of,  167 
Insect  world,   at  close  range,  the,   19 

geography,  of,  24,  25 
Isopoda,    171 


Joseph  Land,    169 
Jungle,   Andean,   166 


Faroe  Islands,   169 
Filistata,   48 

Fistulare,   Sceliphron,   60 
Fly,  bombyliid,  150 

checker,   89 

flesh,  79 

greenbottle,   129 

method  of  feeding,  131 
benefit  derived  from,   133 

house,  79 

robber,  128 

trepetid,  life  history  of,  78 
erergence   of,   83 
pigmentation    of    pupa,    83,    84 
Flies,  78,  79,  83,  84,  89,  128,  129,  131,  133,  150 
Forest  shell-wasp,  the,  53 

life  history  and  habits  of,  54 
Formica   sanguinea,   112 

exsectoides,  134 
France,    170 


Gasteracantha,   48 

Geological  past,  living  examples  of,   169 

Gibbosus,   Philanthus,   85 

Gongylophosa,   Rozites,    115 

Graham  Land,   169 

Grasshoppers,    122 

Guiana,  British,  118,  165 

H 

Hamatus,  Zethusculus,   53 
Harvestman,   120 
Heliconidae,    167 
Histogenesis,  37,   38 
Histolysis,   37,   38 


Kalacoon,  27 


Larval   sacrifice,   33 

Leucotrichium,    Trypoxylon,   40 

Living  examples  of  the  geological  past,  169 

Longipes,  Emesa,   154 

Lycosidae,    104 

M 

Meloidae,  104 
Micrathena,   48 
Milch  cattle,  134 
Monkey,  howling,  77,  78 
Mosquito,  79 
Moth,  cecropia,  143 

geometrid,  164 
'Myrmeleonidae,   105 

N 

Nature's  way  with  undesirables,  147 
Neotropicus,   Chlorion,    68 
New  Brunswick,   170 

O 

Observations  on  ants,  109-124 
Oil  beetle,  104,  105 
One-banded  dauber,  60 
Original  Paper  makers,  95 
Osmosis,  apparent  of  egg  film,  65 


Pallipes,  Polistes,  95,  101,  138 
Papilionidae,   167 


INDEX 


175 


Paralysis,  artificial  of  spiders,  56 

meaning  of,   51 
Paralyzed  provender,  46,   52 
Pennsylvanicus,   Camponotus,   no,   115 
Phalangidea,  120 

Philanthus  gibbosus,  life  history  of,  85 
Plants,   fertilization  by  insects,  148,  149 
Plexippus,  Anosia,   167 
Podium   rufipes,   33 
Polistes,  pallipes,  95,   101,   138 
Polyergus  rufescens,   112 
Pontius  rapae,  99 
Provender,  paralyzed,  46 
Pupation,  process  of,  35 

controlled,  77,  78,  79,  80,  81,  82,  83,  84 
Pustulata,  Winthemia,  4,  89 


Rapae,   Pontius,   99 

Roaches,  wood,  34,   122,   123 
anatomy  of,  51 
nervous  system  of,  51 

Rozites  gongylophosa,   115 

Rufescens,   Polyergus,    112 

Rufipes,  Podium,  33 


Sandwich   Islands,   169 

Sanguinea,   Formica,   112,   134 

Sarcophagidae,   129,   133 

Sceliphron   fistulare,    60 

Sight  of  insects,   125 

Some  insect  experiments,    134 

South  America,  118,   165,  166,  167,  169 

South  Orkneys,    169 

South   Victoria   Land,    169 

Span-worms,  123 

Speciosus,   Sphecius,  91,   136 

Sphecid's  duty,   the,   91 

Sphecius  speciosus,  91,  136 

Spittle  bug  spittle,   151 

Spittle,   how   produced,   152 

Sphex,   62 

Spiders,  drassid,  25,   104 

anatomy  of,  47 

nervous  system  of,  47 

orb-building,   103 

platform-building,   103,   104 
Spilographa,   78 
Spring-tails,   169 


Tachina,   red-tailed,   89 

Tachininae,   89 

Thecla  butterflies,   165 

Thread-legged    bug,    the    life    of,    154 

Thysanura,   169 

Trailing  a  bee  to  its  lair,  160 

Tree  cricket,   125 


Trepetidae,   78 

Trypoxylon,  cinereohirtum,   27 
leucotrichium,   40 


U 


Undesirables,   Nature's  way  with,   147 


Vanessa,  168 
Vermilion-nut,  77 


W 


Wasps,  Accuracy  of  in  finding  nests,  62,  63,  64 
ancestral  form  of,  36 
appendages,  use  of  pupal,  75 
Black   reed,    life   history   and  habits  of,   27, 

28,  29,  30,  31,  32,  49 
Blue  huntress,  life  history  and  habits  of,  68, 

69,  70,  71,  72,  73,  747  75,  76 
Blue  mud-dauber,   experiments  on,   140,   141 
Cannibal,  life  history  and  habits  of,  85,  86, 

87,   88,  89,  90 

cannibalistic  instincts  of,  87,  88 
characters,  acquired  pupal,  75 
digger,   Great  golden,  91 
egg  film,  osmosis  of,  65 
food,    substitution   of  young   wasp's,    55 
Forest  shell,   life   history  and  habits  of,   53, 

54,   55,   5<S,   57,   5«,   59 
Long   black    reed,    62 
One-banded  dauber,  Life  History  and  habits 

of,  60,  61,  62,  63,  64,  65,  66,  67 
Paper,   effect  of  cold  on,   101 

experiments  on,    138,   139 

food   of  young,   96 

method  of  paper  making,  96,   97 

parasite  of  young,  97 

life  history  and  habits  of,  138,  139 
Prey,   artificial   paralysis  of,   56 

capture  of,   70 

stinging  of,  47 

provisions,  significance  of  choice  of,  42 
Provender,  preparation  of,  47 

pupae,   appearance  of  pigment  in,   58 

cause  of  dull  color  of,  58 
Lumberess,   50,   51,   52 
Mason,  68 

Red-legged    digger,   62 
Roach-killer,   33,   39,  49,   52 
sentinels  of,   100 
Solitary,  food  of  young,   55 

peaceful  nature  of,  91 
Sphecid,  experiments  on,   136,   137 

life   history  and   habits  of,   91,   92,   93,   94 
method  of  carrying  prev,  92,  93 

toilet  of,  94 

squeaking,   interpretation  of,   28 
sting  poisons,   effects  of,  47,  48 


176 


INDEX 


Wasps,  varnish,  44,  46 

victims,   forms  of  paralysis  in,  48,  49 
White-footed,  life  history  and  habits  of,  40, 

41,  42,  43,  44,  45,  46,  47,  48,  49 
sense  of  direction  of,   62 
wings,  unfolding  of,  58,  59 
young,  feeding  stimulus  of,  73,  74 
method  of  feeding,  72,  73 
starvation  of,  67 
varnish  of,  44,   66 
White-footed  wasp,  the,  40 
Wasps,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37, 
38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48, 
49,  SO,  51,  52,  53,  54,  55,  5^,  57,  5?,  59, 
60,  61,  62,  63,  64,  65,  66,  67,  68,  69,  70, 
7i,  72,  73,  74,  75,  76,  85,  86,  87,  88,  89, 


90,  91,  92,  93,  94,  95,  96,  97,  9*,  99, 
101,  136,  136,  138,  139,  140,  141 

Winthemia,  4-pustulata,   89 

Wood-louse,   171 

Worm,  span,   123 


Xenos,  beetle,  97 


Yellow  jacket,  care  of  young,  99 


Zethusculus,    hamatus,    53 


1 

• 

, 

o 

*  W 

o 

o 

Q> 

University  of  Toronto 

1 

r-t 

Library 

DO  NOT 

/ 

_4 

REMOVE 

// 

0 

I 

c\j 
to 

CO 

THE 

•H 

•d 

re 

o 

CARD 

, 

1 

n 

•H 

s 

FROM 

|j 

g 

o 

•H 

THIS 

(d 

§ 

1 

Pi 

^5 

b 

1 
^5 

POCKET 

v 

to 

© 

4-> 

& 

O 

O 

• 

W 

09 

3 

. 

h 

Hi 

o 

~ 

^— 

a 

Acme  Library  Card 

Pocket 

3 

«! 

4-> 

^H 

LOWE-MARTIN  CO.  LIMITED