Insects, etc., InJ2irious to the Vine. 487 



leaf form produces yellow to greenish-red galls of various shapes. 

 The root form, which is the more destructive, causes swellings on the 

 young rootlets, which then decay, and then the aphides collect on the 

 larger roots, which also decay away. During the first year of the 

 insect's attack no very marked symptom^s show, but in the second 

 year, growth is checked and the leaves look yellow and unhealthy. 

 If left the vine dies, and tlie aphides migrate to another if they can. 

 This migration may be in the soil or above the ground. In winter 

 the lice may become torpid and assume a dull brownish hue ; in spring 

 the young lice cast their skins and mature and deposit eggs, and the 

 young from these soon become oviparous females and lay ova again. 

 Several generations of these egg-laying females may occur and in 

 summer winged forms appear. These come above ground and fly 

 from vine to vine and deposit pseud-ova beneath the leaves and on 

 the wood and near the ground. There may also be a migration of 

 actual root forms to the leaves where they form galls. 



The so-called " foundress " Phylloxera has a nearly circular or 

 flask-shaped body of an amber-yellow colour, or she may be ferrugi- 

 nous in hue, spotted from the ova in her body. This form comes from 

 a true egg laid in autumn by the sexual female. If an aerial 

 foundress, she punctures the leaves and becomes enclosed in the 

 swelling mass, and the leaf becomes studded with gall-like bodies. 

 Each foundress forms a single gall within which hundreds of pseud- 

 ova are laid. The galls are round and fleshy and great numbers may 

 occur on a single leaf and the leaves die in consequence. On the 

 roots they form small tubercles, these are caused by the young 

 Phylloxera which have developed in the leaves and have escaped 

 from the galls. It is this subterranean race which causes such harm 

 in Europe, whilst the aerial race is the worst in America — ^^just the 

 reverse of what we see happens with the Woolly Aphis. 



The subterranean females are also amber-yellow and they deposit 

 ova of a pale shiny yellow colour. These give rise to young which go 

 on feeding on the roots and cause the nodules on the fibres and loosen 

 the cortex on the larger roots. In the summer many of these 

 apterous lice become nymphs and come to the surface, where they 

 assume wings and fly about. These winged females produce pseud- 

 ova, and through them true males and females arise. These winged 

 females place the pseud-ova on the down of the underside of the leaves 

 and on the wood. 



The males and females coming from these are very small, and 

 mouthless and wingless. The male is pale ferruginous yellow and 

 the female the same, but larger, and contains but one egg, which she 



