30 SECOND REPORT OF THE STATE ENTOMOLOGIST. 



but continue in bloom for their full period, without any alteration in 

 their appearance. When the operation is completed, if the tongue is 

 applied to a leaf, one can easily understand what has taken place from 

 its very perceptible taste of tobacco. 



The process requires to be repeated in proportion to the extent to 

 which a house is infested. It is not to be imagined that these trouble- 

 some guests are to be quite got rid of by a single operation. A new brood 

 may be hatched on the following day, or some may not have been 

 reached on the first day, so that the vaporization should be frequently 

 carried on until the insects have entirely disappeared, and after that it 

 should be repeated every week, in order to prevent a fresh invasion. 

 (^Country Gentleman.) 



In France, the tobacco juice of the strength above stated, can be 

 purchased of the tobacco factories at about twelve or fifteen cents (our 

 money) a quart, by presenting a certificate that it is to be used for kill- 

 ing insects. The expense, at this rate, would be very trifling, being only 

 about twenty-five cents a week for a plant-house fifty feet long by six- 

 teen broad and ten high. 



A strong infusion of tobacco leaves made by boiling, would be a sub- 

 stitute for the above factory juice. It might be prepared in quantity 

 and evaporated for convenience of keeping and ready use, to the proper 

 degree. 



The " Thrips," for the killing of which the vaporized tobacco juice is 

 recommended, is a popular name which has obtained currency among 

 vine-growers for a small (about one-eighth of an inch long), slender, 

 spindle-shaped, parti-colored leaf-hopper, which in its larval, pupal and 

 perfect stages is very destructive to the foliage of grapevines. It attacks 

 the leaves by puncturing them with its proboscis, usually upon the under 

 side, withdrawing the sap and causing small discolored spots over their 

 surface. The spots increase in size and number by coalescence and 

 the growth of the insect, becoming later, large, brown blotches, which 

 gradually extend, if the attack is severe, over the entire leaf, until it 

 dries, appearing as if scorched by fire, dies, and falls from the vine. 

 The fruit is dwarfed, fails to ripen, or the vine is killed, according to 

 the abundance of the insects. 



It is believed that several distinct species are usually associated in 

 this attack, belonging to the genus Erythroneura, of which the princir 

 pal one is that described by Dr. Harris in the year 1831, under the name 

 of Tettigonia vttis, a figure of which (pronounced a poor one by Mr. 

 Walsh*) is given in Plate 3, of Insects Injurious to Vegetation. 



*A better one may be found in the Practical Entomologist, ii, p. 51, which has been 

 copied in Packard's Guide to the Study of Jnaects, in Saunder's Insects Injurious to Fmiti, 

 and in other recent publications. 



