118 BRITISH APHIDES. 



Body wholly black, with irregular patches of mealy 

 matter, which also powders the wings. Head small 

 and round. Antennae six-jointed, the third, fourth, 

 and fifth being dissimilarly ringed, the sixth smooth 

 and ending with a nail. Abdomen long-oval, smooth, 

 cylindrical, and mealy. Legs short and black. Eyes 

 moderately large and black, AYings with smoky mem- 

 branes. All the veins are black. Cubitus and stigma 

 smoky grey. The two oblique veins of the fore wings 

 take their origin from almost the same point of the 

 cubitus. The third vein does not touch the cubitus 

 by one third of its length. In the hind wings the 

 oblique veins so unite to the costal nerve as to form a 

 kind of trident. All the veins are black. 



These winged females are very prolific, bringing 

 forth oblong, smooth, yellow-coloured young, which 

 appear like ova at the time of their birth. Six of 

 these young were born and disengaged themselves 

 from their enveloping membranes within the short 

 space of an hour and a half. 



I have gathered galls in plenty during the month of 

 June, formed by swellings of the petioles of the leaves 

 of Populus nigra and P. dilatata. They occur in many 

 parts of England. I have picked them at Haslemere, 

 Chichester, and Walthamstow. They are also common 

 in the South of France, and at Spa in Belgium. These 

 purses are pear-shaped or long-oval, with small open- 

 ings at their summits, which gradually widen and 

 have usually a number of pink corrugations at their 

 edges. 



Towards the beginning of July the winged females 

 come out of their pupae, and on the access of the 

 sun's rays issue forth in great numbers in order to 

 spread elsewhere. When cut into, these galls disclose 

 a single chamber, formed of thick fleshy walls ; which 

 a high magnifying power shows to have a dense 

 cellular structure. The cavities contain a quantity of 

 those previously noticed spherical globules, which are 

 of a mucilaginous nature. 



