—  789  — 
I 
winter  eggs  deposited  in  cracks  or  under  loose  bark  on  the  trunks  of  tile 
maples,  in  April  travel  upward  to  the  branches  and  settle  on  the  midrib  of 
the  underside  of  young  leaflets.  Here  they  give  rise  to  a  generation  of  larvae 
sucking  on  the  leaf,  in  consequence  of  which  the  leaf  folds  from  the  midrib 
downward,  while  the  colony  covers  itself  with  an  abundant  cottony  secretion. 
All  of  these  larvae  du- 
ring June  and  July 
develop  into  winged 
migrants  that  fly  to 
the  Alders  and  settle 
on  the  underside  of 
leaves.  The  larvae  de- 
posited by  these  mi- 
grants almost  imme- 
diately move  to  the 
bark  of  the  twigs  or 
stems  and  give  rise  to 
vast  colonies  covered 
with  cottony  secretion 
and  sucking  on  the 
bark  in  many  apterous 
generations  till  late 
in  the  autumn.  These 
generations  have  been  described  under  the  names  of  Eriosoma  tessellata 
Fitch,  Sclmoneura  tessellata  Thomas,  Pemphigus  aim  Provancher,  and 
Pemphigus  tessellatus  Osborn.  They  live  on  various  species  of  the  Aider. 
American  and  foreign.  From  the  middle  of  September  to  the  middle  of 
October,  numerous  winged  individuals  (the  Sexuparae)  appear  among  them, 
which  fly  back  to  the  trunks  of  the  maples  where  they  produce  the 
typical  small  males  and  females  (the  Sexuales),  and  the  latter  deposit  winter 
eggs.  The  apterous  viviparous  Aphides  still  remain  on  the  Alder  and  keep 
on  producing  additional  larvae,  all  of  which  crawl  down  the  stems  or  even 
to  the  roots,  where  they  hibernate  and  grow  until  mature  in  the  following 
- 
-pring. 
Pergande  names  the  described  species  Prociphilus  tessellatus  Fitch, 
but  he  makes  no  mention  of  the  groups  of  waxen  glands  on  the  head  and 
thorax  characteristical  of  the  genus  Prociphilus  Koch,  and  he  does  not 
figure  them  (Fig.  3).  It  is  also  to  be  concluded  that  the  species  in  question 
Извѣстія  P.  A.  E.  1919. 
Fig. 
Winged  migrant  Pemphigus  tessellatus  Fitcli  and  antenna, 
magnified.  After  Pergande. 
