162 
Inseds  Injurious  to  Drugs. 
j  Am.  Joiir  Pliarm. 
t      April,  lb8;i. 
Tenehrioides  mauritanicay  a  species  of  "  meal-worm/'  was  found  in 
pearl  barley,  and  one  specimen  in  calumba.  It  is  a  dark  brown  beetle, 
five-sixteenths  of  an  inch  long,  the  head  and  thorax  forming  nearly 
half  the  total  length,  and  the  mouth  being  fringed  with  hair.  The 
back,  which  at  first  sight  appears  perfectly  smooth,  proves  to  be,  Avhen 
examined  under  the  microscope,  longitudinally  corrugated .  The  larva 
is  nearly  half  an  inch  long,  white,  with  a  brown  head,  and  between  the 
jaws  is  a  row  of  hair  as  in  the  perfect  insect.  The  posterior  end  is 
furnished  with  a  pair  of  jaws  very  similar,  though,  of  course,  for  a 
different  pui'pose. 
Trebol'mm  fwrrugmeiun  is  a  flat,  reddish-brown  beetle,  about  one- 
eighth  of  an  inch  long,  appearing  smooth  to  the  naked  eye,  though  the 
microscope  shows  the  back  numerously  pitted.  These  insects  affect 
patent  foods  and  similar  substances,  and  the  beetles  are  possessed  of 
remarkable  longevity,  as  proved  by  the  fact  that  I  have  kept  a  few 
alive  for  two  months  in  a  small  box  with  a  little  cerealina,  which 
seems  to  be  their  favorite  food.  Whether  the  beetles  themselves  eat  it 
or  not  I  do  not  know,  but  they  certainly  have  a  liking  for  the  dead 
bodies  of  other  beetles. 
Silvanus  surinamensis  is  a  narrow,  brown  beetle,  almost  one-eighth 
of  an  inch  long,  with  a  pitted  and  longitudinally  corrugated  back. 
One  specimen  only  was  found,,  on  anthemis. 
Anthrenus  varius. — This  insect  has  been  found  only  in  cantharides, 
but  I  believe,  also  attacks  other  animal  drugs,  such  as  castoreum. 
During  the  month  of  July  there  emerges  from  the  egg  a  very  active 
larva,  densely  covered  on  the  tops  of  the  segments  with  stifP  brown 
hairs,  which,  at  the  posterior  end,  point  towards  the  centre  of  the  back, 
form  a  ridge,  and  when  the  insect  is  annoyed,  it  has  the  power  of 
dividing  the  ridge  in  the  centre  and  throwing  half  down  on  each  side 
in  a  fan-like  position,  the  object  of  which  movement  could  not  be 
determined.  When  the  insect  has  been  feeding  on  the  whole  cantha- 
rides, all  these  hairs  on  the  back  become  rubbed  off,  those  forming  the 
ridge  being  generally  last  to  go,  because,  being  on  the  downward  slope 
of  the  body  they  are  not  exposed  to  the  same  amount  of  friction. 
Underneath,  however,  the  hairs  are  shorter,  and  do  not  become  rubbed 
off  as  on  the  back. 
The  larvse  consists  of  eleven  segments,  those  at  the  ends  being  of  a 
much  deeper  brown  than  those  towards  the  middle,  and  the  six  legs 
being  inserted  on  the  three  anterior  segments,  each  furnished  with  a 
