BULLETIN 198. THE GRAPE LEAF-HOPPER. 199 



Gillette, in the publication cited, states that coloradensis is a very 

 distinctly marked variety and one that seems to be confined entirely 

 to the West. This does not mean that it is limited to the Pacific coast 

 states, for it occurs commonly in Colorado, and it is also found in 

 Nebraska, Kansas, and New Mexico. Specimens of the California 

 varieties were sent to Professor Gillette and he replied that they were 

 the typical comes and coloradensis, the same as he would collect on the 

 grape in Colorado. So far as we know, none of the other eight varieties 

 of the species have been recorded from this State. 



The Common Name of the Insect. The insect treated of in this 

 bulletin is probably best known by the ^ineyardists of the State as the 

 "thrips" or "vine thrips." This name, however, is improperly applied 

 to this insect, since the term "thrips" rightly belongs to insects of 

 a different group. The true thrips, if they have any wings at all, have 

 delicate fringe wings, and are not so active as the leaf-hopper. The 

 thrips are very small, slender bodied insects, ranging from yellowish 

 to black in color, and will be most easily found in flower cups, where 

 they feed upon the sap of the different parts of the flower as well as 

 upon the leaves. There are several injurious species of thrips, but none 

 do much damage, so far as observed, to the grape. One particular 

 species has become a very important pest to fruit trees in the Santa 

 Clara Valley. To avoid confusion, therefore, the term ' ' thrips ' ' should 

 be applied to such an insect as this in the Santa Clara Valley and 

 elsewhere. 



The common name of the insect discussed in this bulletin, as 

 adopted by the Association of Economic Entomologists is the "grape 

 leaf -hopper. " This is generally shortened in this State to simply 

 "hopper" or "vine hopper," and this may be specific enough here, since, 

 when we speak of "vine" alone there is no mistaking the kind of vine 

 referred .to ; and it is generally understood that all hoppers feed on the 

 leaf. However, the correct common name of the insect, as officially 

 adopted, is the Grape leaf-hopper. 



Preference for Different Varieties of Vines. In many vineyards 

 infested with vine hoppers it will be noticed that certain varieties of 

 vines will be much worse attacked than certain other varieties. It 

 may be easy, in the case of a single vineyard, to express in definite 

 terms the preference shown by the hoppers for particular varieties; 

 but in another vineyard in the same neighborhood these conditions may 

 be almost reversed, so that one is hardly warranted in making a general 

 statement that will apply to all conditions and all situations. 



However, certain facts were observed which may indicate a choice 



