PLATE CXI. 



Pemphigus bursarius. (Page 117.) 



Fig. 1. — Queen Apliis — apterous female. 



Fig. 2. — Pupa with circular wliite mealy patches, 

 like the above queen. 



Fig, 3. — Imago, with young, which last have by 

 some been mistaken for ova. The angular veining of 

 the hind wing differs from the foregoing species. 



Fig. 4. — Leaf of poplar, the foot-stalk of which has 

 been punctured by the Queen Aphis. Two purses are 

 here formed with corrugated openings, through which 

 the winged females escape. This form of gall is 

 thought by Lichtenstein to be the work of a species 

 which he proposes to call P. pyriformis. He con- 

 siders the round gall (PI. CXIII, fig. 7) to be the work 

 of Pemphigus bur sarins. 



Fig. 5. — Section of a pyriform gall, natural size, 

 showing within the cavity the Aphides covered with 

 mealy dust. 



Fig. 6. — Antenna of fig. 1. 



Fig. 7. — Antenna of imago (fig. 3). 



Pemphigus spirothec^. (Page 122.) 



Fig. 8. — Apterous viviparous female, covered with 

 white down. 



Fig. 9. — Bottle-like gall, found on the stem of the 

 black poplar {Populus nigra). Probably an abnormal 

 form, and the work of Pemphigus spirothecce. The 

 normal spiral " galls " are represented in PL CXII, 

 figs, i— 3. 



