THE LOUSE. 271 



Thit which feme have called the Leaf-Louse, is the fize of a fiea ; 

 bright green, or blueilh green colour; the body nearly oval, largefl: and 

 mod convex on the hinder part j the brep.ft very fmali, the head blunt 

 and green ; the eyes are prominent on the fore-part of the head, of a 

 ftiining black ; near thefe, is a black line on each fide j the legs are very 

 flender. Thefe are uiually found on tfie leaves of the orache» and other 

 plants ; and the weaker the leaves and buds, thefe infecls fwarm in greater 

 abundance. Some plants are covered over with them. They do not 

 caufe the plant's weakneis, but by wounding and fucking the leaf they 

 increafe the difeafe. They generally alTume their colour from the plant oa 

 which they refide. Thofe on pot-herbs and plum-trees, are afh-colour- 

 ed, but greenifh when young ; thofe of the alder and cherry tree, are 

 black, alfo thofe on beans and fome other plants; thofe on the leav s of 

 apples and rofe-trees, are white : as thefe leap like grafshoppers, lome 

 place them in the number of the flea kind. The moft uncommon colour 

 is reddifh, and this fort is found on the» leaves of tanfey ; and their juice, 

 when rubbed on the hands, tinges them red. AU thefe live on their re- 

 fpeclive plant, and are often engendered within the very fubftance of 

 the leaf. 



Thefe bring forth their young alive j their fore-parts being excluded 

 firft. Its provifion lying beneath it, during fummer it eats and creeps 

 with great agility : for winter it endeavours to fecure a retreat near trees 

 or plants that nourifti it in fpring. They never hide in the earih, be- 

 caufe they have no part fitted to remove earth ; nor can they creep into 

 every chink, as their legs are long, and their bodies fo tender, the ]cafb 

 rough particle of earth would hurt them ; but they get into the dc.p 

 chinks of the bark, and the cavities of ftronger ftalks. As neither the 

 temperature of autumn nor fpring hurts them, they feldom fcek hiding- 

 places before the fall of the leaf, and take the earlieft advantage of return- 

 ing warmth. They caft their (kins four times ; the males have four 

 wings, the females none. They have long legs, to creep over the long 

 hairs of plants and leaves, or to travel from tree to tree when diflant. 

 Their trunk or fnout lies under the breaft; this they thruft into the pores 

 of the plant, and fuck out the juice j but fo hurt the leaves byTuck:ng, 

 that they become ipotted and fcabbed, their cdgts always turning up. 

 The leaf-loufe is more than a match for the ant at fingle combat. When 

 they perceive the ant approaching behind them, they kick back with their 

 iiinder feet, and drive off the invader, as a horfc would a lion. 



The three principal and conftant enemies to thefe infeds are, firft, the 



Z z 2 fire- 



