FORDA VIRIDANA. 85 



Mr. "Walker obtained Forda from the roots of the 

 sow-thistle, Sonchus oleraceus. 



The habits of Forda formicaria are not apparently in 

 all cases subterranean. I have taken them in April at 

 Haslemere on the green leaves of Triticum repens just 

 above the surface of the ground. I have represented 

 such a modified habit in the plate above alluded to. 



Koch figures and describes another species of 

 this genus under the name Forda marginata. It is 

 yellowish-white, and possibly may be the same insect 

 as I figure, but the diagnosis agrees only in part. 



Forda viridana, Bucldon. Plate CXXVII, figs. 1, 2. 



Viviparous female. 



Inch. Millimetres. 



Size of the body 0*080 X 0*050 2*03x1*26. 



Length of the antennas 0*035 0'88. 



Oval, dull, pilose, and velvety. Colours variable, 

 from rich chocolate-brown and mouse-brown to an 

 emerald-green ; legs and antennae ginger-brown. 

 Vertex setose. Eyes very small and inconspicuous. 

 Thorax and abdomen much corrugated and domed ; 

 nectaries none. Rostrum long, about three-fourths 

 the length of the body. Tail blunt and carried slightly 

 erect. Claws double, but often seen folded as if they 

 were single. 



Taken in small companies in Ants' nests covered by 

 tufts of various grasses. It differs from the preceding 

 species in several particulars, and chiefly in beiug 

 smaller, more pilose, and deficient in the green dorsal 

 stripe. 



It occurs throughout May and June in the dry 

 moors, near Wooler, in Northumberland. 



Mr. James Hardy informs me the " malachite-green 

 variety " may often be taken in quantity, nesting with 

 Formica fidiginosa. This Aphis is particularly plentiful 



