г-  788  — 
Besides  there  are  secondary  rhinaries,  namely  9  —  10  ones  on  the  third 
joint,  and  4  ones  on  both  the  joints  4.  and  5.,  while  the  joint  6.  has  no 
secondary  rhinaries  at  all.  The  antennae  of  the  viviparous  apterous  indivi- 
duals are  about  0,75  mm.  long,  and  they  are  provided  with  only  a  single 
primitive  rhinary  on  the  joints  5.  and  6.,  while  ,  the  relative  length  of 
the  joints  is  the  same  as  in  the  winged  individuals.  The  length  of  the  fore- 
wing  is  4,5  mm. 
Since  no  palaearctic  species  of  the  genus  Pemphigus  living  on  the 
Alder  trees  is  hitherto  known,  it  appears  very  probable  that  we  have  a  new 
species  to  deal  with.  But  this  question  could  not  be  decided  before  consulting 
the  diagnosis  of  the  American  species  Pemphigus  alni  living  on  Alder  trees 
in  Canada  and  described  by  the  Abbe  L.  Provancher  l.  Being  unable  to 
procure  the  paper  of  this  author  because^  of  the  interrupted  communication 
with  the  foreign  countries,  and  ha  ving  not  found  it  in  the  libraries  of  Petrograd, 
Fig,  2,  An  antenna  of  the  viviparous  apterous  Pemphigus  baicalensis  sp.  n.  Zeiss  ÄA,  Oc.  4. 
I  postponed  the  description  of  the  Aphides  in  question.  But  newly,  revising 
my  own  aphidological  library,  I  met  a  paper  of  Theo.  Pergande  containing 
a  detailed  quotation  of  the  Provancher's  description  of  his  Pemphigus 
ami ,  and  further  an  account  of  the  life  history  of  this  species  given  by 
Pergande  himself  on  the  ground  of  his  own  investigations  during  many 
years  2.  From  this  description  and  from  the  figures  added  to  it  I  came  to 
the  conviction  that  our  Transbaicalian  species,  although  closely  allied  to  the 
American  one,  still  differs  from  the  latter  in  some  peculiarities, — certainly 
admitting  that  the  description  and  the  figures  given  by  Pergande  are  quite 
exact,  which  however  is  scarcely  to  be  doubted. 
The  American  Alder-tree  Pemphigus  proves  to  live  on  the  Alder  only 
as  on  an  intermediate  plant,  its  principal  food  plant  being  the  maple 
(Acer  dasycarpmn,  A.  eriocarpum).  The  species  in  question  has  first  been 
described  on  the  maple  under  the  names  of  Aphis  stamineus  Haldeman 
and  Pemphigus  acerifolii  Riley.  Young  stemmothers  hatched  from  the 
1  L.  Provancher.  Petite  Faune  Entomologique  de  Canada,  vol.  8,  1886,  p.  320. 
2  Theo.  Pergande.  The  Life  History  of  the  Alder  Blight  Aphis.  Washington  1912 
(U.  S.  Department  of  Agriculture,  Bureau  of  Entomology,  Technical  Series,  №  24). 
