158 
VESICATING  PRINCIPLE  OF  LTTTA  VITTATA. 
usually  in  one  or  two  drops,  from  a  corresponding  number  of  the 
knees,  though  smaller  drops  are  not  unfrequently  seen  to  ap- 
pear at  other  joints  of  the  legs.  This  liquid  appears  to  be  the 
blood  of  the  animal,  for  it  is  in  all  its  physicomicroscopical 
characters  like  this  fluid  obtained  from  any  part  of  the  body. 
If  an  elytrum  is  cut  across,  one  or  two  drops  of  the  same  liquid 
exudes  from  vessels  of  the  cut  margin.  The  liquid  forms  a  fibrin- 
ous coagulum,  and  contains  colorless  corpuscles,  like  the  blood 
of  insects  ordinarily.  The  exudation  occurring  on  the  capture  of 
the  Lytta,  I  suspect  to  be  the  result  of  voluntary  rupture  of  the 
parts,  which  is  not  extraordinary  when  we  take  into  considera- 
tion the  ease  with  which  insects  will  sacrifice  a  leg.  Be  it  as  it 
may,  the  yellow  liquid  from  any  part  of  the  body  vesicates. 
Portions  voluntarily  exuded  on  the  capture  of  the  insect,  others 
from  the  cut  borders  of  the  elytra,  from  cut  extremities  of  the 
legs,  and  from  the  head,  imbibed  by  separate  portions  of  bibu- 
lous paper  produced  upon  the  inner  side  of  my  forearm  a  cor- 
responding number  of  blisters.  As  the  nettle  among  plants, 
and  the  larva  of  the  egger  moth  have  stinging  hair,  I  was  led 
to  try  those  of  the  Lytta.  A  quantity  scraped  from  the  elytra 
and  other  parts  were  mixed  with  cerate  and  applied  to  my  fore- 
arm.   They  proved  to  be  inert. 
Half  a  dozen  elytra  cut  into  fragments  and  mingled  with 
cerate  produced  a  blister.  This  was  the  result  of  the  contained 
yellow  liquid  or  blood,  for  a  nearly  entire  elytrum  vesicated 
only  at  the  point  of  contact  of  the  cut  border. 
The  intestinal  canal  with  its  leafy  contents  produced  no  effect. 
The  muscles  of  the  thorax,  and  the  rete  adiposa,  or  fatty  matter 
common  in  insects,  separately  applied  to  the  forearm,  pro- 
duced no  effect.  The  testicle  and  epididymis  of  the  male 
likewise  were  inert ;  as  were  also  two  long  tortuous  accessory 
glands  of  the  generative  apparatus  in  the  same  sex.  Two  other 
accessory  glands  of  the  generative  apparatus  in  the  male,  equal- 
ly long  and  tortuous  with  those  just  indicated,  are  distended  with 
an  opaque  white  granular  matter.  This  matter,  mingled  with 
cerate,  was  found  to  be  highly  vesicant.  Viewed  with  the  mi- 
croscope it  seems  to  be  a  consistent  fat-like  substance ;  appear- 
ing as  spherules  of  various  sizes  with  dark  outlines,  fainter  con- 
centric lines,  and  others  radiating.    The  spherules  recalled  to 
