360 
Annual  Report  for  1909  of  the  Zoologist. 
Parasitic  Diseases  of  Animals. 
A good  many  of  the  applications  for  advice  received  by 
the  Zoologist  related  to  the  diseases  of  domestic  animals,  but 
some  of  them  would  have  been  more  properly  referred  to  the 
Veterinary  Department.  Cases  were  reported  of  “ gapes  ” 
in  pheasants,  and  of  the  intestinal  worm  Sclerostomum 
hypostomum  in  sheep,  as  well  as  of  warble-fly  and  numerous 
external  parasites  on  various  animals.  Creatures  found  living 
in  water  to  which  domestic  animals  had  access  were  often 
sent  for  identification  with  a view  to  ascertaining  whether 
they  were  likely  to  be  harioful.  These  included  certain 
worms,  and  the  different  animals  known  as  “water-fleas” 
{Collembola,  Daphnia,  &c.).  In  most  cases  the  creatures 
themselves  were  innocuous,  but  they  sometimes  indicated  a 
somewhat  foul  condition  of  the  water  which  rendered  it 
unsuitable  for  drinking  purposes,  and  it  is  important  to 
remember  that  many  of  the  internal  parasites  to  which 
animals  are  subject  are  acquired  from  polluted  water  supplies. 
A rather  interesting  worm  sometimes  sent  in  this  connection 
is  the  “ Hair-worm,”  known  scientifically  as  Gordius,  from  the 
“ Gordian  knot  ” into  which  it  ties  itself.  It  is  very  slender, 
and  about  four  inches  long.  Its  early  life  is  spent  as  an  internal 
parasite  of  certain  water  insects — the  May -fly  larva  for  instance 
— but  when  adult  it  is  free-living,  and  harmless  to  higher 
animals.  For  ages  a very  curious  superstition  was  current  with 
regard  to  it ; it  was  believed  that  a horse’s  hair,  falling  into  the 
water,  became  a hair-worm,  and  later  developed  into  a serpent. 
Miscellaneous  Notes. 
A correspondent  who  entertains  the  belief  that  wasps  are 
at  least  as  useful  as  they  are  injurious,  has,  during  the  past 
summer,  taken  many  wasps’  nests  and  sent  me  hundreds  of  the 
captured  wasps  to  ascertain  the  species  and  the  kinds  of  insects 
which  the  workers  are  taking  to  the  nest  as  food  for  the  young. 
The  detailed  results  will  probably  be  published  elsewhere,  but 
a few  notes  on  the  subject  will  not  be  out  of  place  in  the  present 
report. 
To  the  casual  observer  the  wasp  appears  to  be  an  unmitigated 
nuisance,  on  account  of  the  damage  it  does  to  fruit.  It  is  not 
as  generally  known  as  it  should  be  that  the  wasp-grubs  are 
exclusively  reared  on  insect  food,  the  worker  wasps  catching 
insects,  chewing  them  to  a pulp,  and  feeding  them  into  the 
mouths  of  the  grubs  in  the  cells  of  the  wasps’  nest.  Conse- 
quently, taking  the  whole  life  of  a wasp,  far  more  insect  food 
than  fruit  food  is  devoured,  and  if  it  should  prove  that  most  of 
the  captured  insects  were  injurious,  it  would  follow  that  wasps 
