THE PRACTICAL ENTOMOLOGIST. 



51 



is very hard on the buds of the grape-vine, and af- 

 terwards on the leaves. Those who wish to know 

 more about it, are referred to an excellent article 

 on this insect by Mr. J. Kirkpatrick, which has 

 been reprinted in the Practical Entomologist 

 (I, p. 40.) 



Well, Messieurs vine-growers, is this your 

 Thrlps? I should say it must be Mr. Meeker's 

 Thripx, becau.se he expressly .says that his "Thrips" 

 "eats the leaves till they appear like shreds," (see 

 Pr.^ctical ENTOJroLOGisT, Vol. I, pp. 21 — 2,) 

 and the insect to be next noticed has no jaws at all 

 to eat with, only a beak to suck sap with. Likely 

 enoujih, however, different vine-growers call differ- 

 ent insects by one and the sanje name — "Thrips." 

 So we will 'bout ship and try another tack. 



The annexed figure represents the Leaf-hopper 

 of the Grape-vine, the TctHijonia' {fri/tlironcura) 

 vitis of Harris. That to the left shows the per- 

 fect insect with expanded wings; that to the right 

 the same insect with its wings closed. The hair- 

 lines show the natural length of the insect, the fi- 

 gures themselves being considerably magnified. In 



Colors, pale-yellow and blood-hrown. 

 Harris's Injurious Iiiupcfs (Plate III, fig. 5,) may 

 be found a very poor colored figure of this same 

 species, but the wings, as represented there, are 

 out of all drawing, and the coloring is exaggerated. 

 This Leaf-hopper is one out of five quite distinct 

 species — all belonging to the same genus, and all of 

 thesameshapeandsizeibutdifferingin their coloring 

 — which often swarm in varied proportions on the 

 leaves of the grape-vine in the U. S. Two of the five 

 have been described by Dr. Fitch as ErytJironeura 

 vulnerata and E. tn'ri'iictu, and two by myself as E. 

 ztKac and E. 8-notata; and I have recently receiv- 

 ed from Canada two other species, also distinguish- 

 ed by their coloring alone, which are as yet unde- 

 scribed and unnamed, and which swarm there on 

 the grape-vine in company with some of our U. S. 

 species. In all the above species the larva diff"ers 

 from the perfect winged insect chiefly in having no 

 wings, and is equally destructive to the vine, 

 pumping away in great crowds at the sap upon the 

 lower surface of the leaf, and causing there numer- 

 ous brown dead spots, so as to often kill the leaf 

 entirely, and sometimes, when the insects are ex- 

 ceedingly abundant, to kill the whole vine. Both 

 larva. and perfect insects jump like any flea, but of 

 course it isonlythe perfect wingedinsectthathasthe 

 power of flying. Unlike the Flea-beetle that we were 

 looking at just now, the hind thighs are not thick- 

 ened, but the entire hind leg is greatly elongated 

 and armed with rows of little thorns, as in the 



Grasshoppers, which enables it to jump with great 

 vigor. Like almost all other species belonging to 

 the Order Homoptera, they have a peculiar habit 

 of running sideways like a Crab; and when they 

 see you looking at them upon one side of a leaf, 

 they will often dodge round quickly to the other 

 side, as a squrrel dodges round to the opposite side 

 of the trunk of a tree when he sees that he is no- 

 ticed. Insects are more wide-awake than people 

 generally suppose. The high and low vulgar de- 

 spi.se them because they are comparatively small. 

 But their habits are as interesting, and their struc- 

 ture as complicated and wonderful, as those of the 

 higher and larger animals. In some cases their 

 structure is even more complicated than in the 

 higher animals ; for Lyonnot demonstrated that 

 there were 4000 distinct muscles in the body of a 

 single caterpillar, and in Man — the highest of cre- 

 ated animals — there are only 529 muscles. God 

 took just as much pains in making one of these 

 poor despised little creatures, as in making a Whale 

 or an Elephant. Yet he that dissects an Elephant 

 is, in the popular eye, a distinguished and a learn- 

 ed man, and he that dissects a Fly is a fool and a 

 '•bug-hunter!" 



I said just now, that there were no less than 

 seven distinct species of Leaf-hoppers, all of the 

 same shape and size, but differing in coloration, 

 which commonly infested the Grape-vine in North 

 America. "But," some one will reply, "may not 

 some of these seven be mere varieties, and not 

 true species ?" The answer is, that I have careful- 

 ly compared together scores, and in some cases hun- 

 dreds of each supposed species, taken on the same 

 day, off" the same grape-vine, and clearly ascertain- 

 ed that there are no intermediate grades, and that 

 one supposed species does not fade away gradually 

 into another. Neither can it be the ca.se, that any 

 two supposed species are merely the opposite sexes 

 of one and the same species ; for in this whole Or- 

 der of In.sects the sexes are distinguished with the 

 greatest ease, and both males and females are found 

 belonging to each of the seven species referred to 

 above. Hence we may infer with certainty that 

 they are true species, not mere varieties, and that 

 each species, as a general rule, interbreeds with it- 

 self alone. For, if any two of the seven bred pro- 

 miscuously with one another, we should inevitably 

 often find intermediate varieties; just as when you 

 cross a Fantail Pigeon with a Tumbler Pigeon, 

 you produce a mongrel pigeon which is neither 

 Fantail nor Tumbler, but something intermediate 

 between the two. 



And now once more, Messieurs Vine-growers, ia 

 this your "Thrips ?" Or, if neither of the above 

 two is your "Thrips," what in heaven's name is it? 



Postscript — Since the above was in type, the mystery 

 has been cleared up — the enigma has been unriddled — and 

 like Archimedes, when he had solved his knotty problem, 

 we may exclaim Eureka ! The so-called "Thrip" of the 

 Western vine-growers, as it turns out, is really nothing 

 but Grape-vine Leaf-hopper, {Tettigonia vitis) — at least so 

 says the Committee on Entomology in their Report to the 

 Missouri State Horticultural Society. (A<jr. Rep. Missou- 

 ri., 1865, App. p. 342.) Now then at last we know what a 

 "Thrip" is; and the patient reader, who has joined me in 

 this Pursuit of Knowledge under Difficulties, can see the 



