55 



had been at its destructive work for years, producing injury the true cause of which was 

 never suspected until the publication of the article in my fourth Report. I also showed that 

 some of our native varieties enjdjed relative immunity from the insects' attacks, and urged 

 their use for stocks, as a means of re-establishing the blighted vineyards of Southern 

 France." 



" The disease continued to spread in Europe, and became so calamitous in the last- 

 named country that the French Academy of Sciences appointed a standing Phylloxera Com- 

 mittee. It is also attracting some attention in Portugal, Austria and Germany, and even in 

 England, where it affects hot-house grapes." 



Natural History of the Insect. 



The genus Phylloxera is characterized by having three-jointed antennas, the third or 

 terminal being much the longest, and by carrying its wings overlapping, flat on the back in- 

 stead of roof- fashion. It belongs to the sub-order of whole-winged bugs (Uomoptera), and 

 forms a connecting link between two of its great families, the V\!mt-\ice(Aphidida') on the 

 one hand, and the Bark-lice {Coccidce) on the other. It is generally considered, however, to 

 pertain to the former family, though some naturalists, with the not uncommon love of intro- 

 ducing new names and minute classifications, have desired to found a new family for this 

 sjiecial insect. 



Not the least interesting feature in the economy of the Phylloxera is the different phases 

 or forms under which it presents itself Among these forms are two constant types which 

 have led many to suppose that we have to do with two species. The one type, which for 

 convenience Mr. Riley terms yalkecola, lives in galls on the leaves ; the other which he calls 

 radickola, lives on swellings o'" the roots. They may be tabulated thus : — 



Type 1. OalUecola (see Figure 43,/, g, h), 

 Type 2. Iladicicola. 



A, Degraded or wingless form (see Figure 44, e, f, g.) 



B, Perfect or winged form (see Figure 45, g, h.) 



" TypE Gall.«;cola or Gall-inhabiting. — The gall or escrescence produced by this 

 Insect is simply a fleshy swelling of the under side of the leaf, more or less wrinkled and 

 hairy, with a corresponding depression of the upper side, the margin of the cup being fuzzy, 

 and drawn together so as to form a fimbriated mouth. It is usually cup-shaped, but some- 

 times greatly elongated or purse-shaped. 



Soon after the first vine-leaves that put out in the spring have fully e.^panded, a few 

 ''''■'■ *"-• scattering galls may be found, mostly on the 



lower leaves, nearest the ground. These ver- 

 nal galls are usually large, (of the size of an ordi- 

 nary pea), and tlie normal green is often blushed 

 with rose where exposed to the light of the sun. 

 ( )n carefully opening one o'" them (Fig. 4.'^, d) we 

 shall find the mother-louse diligently at work 

 surrounding herself with pale yellow eggs of an 

 elongate oval form, scarcely .01 inch long, 

 and not quite half as thick (Fig. 43, c). She is 

 about .04 inch long, generally spherical in .shape, 

 of a dull orange colour, and looks not unlike an 

 immature seed of the common purslane. At 

 times, by the elongation of the abdomen, the 

 shape assumes, more or less perfectly, tiie pyri- 

 form Her members are all dusky, and so short 

 compared to her swollen body, that she appears 

 very clumsy, and undoubtedly would be out- 

 side of her gall, which slie never has occasion 

 to quit, and which serves her alike as dwelling-house and coflin. More carefully examined, 

 her skin is seen to be shagrccned or minutely granulated and furnished with rows 

 of minute hairs. The eggs begin to hatch when six or eight days old into active 



Under side of Leaf covered with Galls. 



