18 



THE PRACTICAL ENTOMOLOGIST. 



der the most favorable circumstances, might be pro- 

 duced i'rom one of these insignificant, lice-like, al- 

 most microscopic creatures. From such reflections 

 (hat fii;iiros force upon our consideration, (and "fi- 

 ;;;uri:s don't lie,") we can easily learn to appreciate 

 the importance of destroying, if it be but one noxi- 

 ous insect ; and much more of preserving and fos- 

 tering as our own life its insect enemies. 



This year, by the middle of July, I saw the .se- 

 cond young brood of coccus, by the aid of a glass, 

 so numerous as to literally cover the upper side of 

 the young expanding leaf, while its sides were yet 

 folded together. In these cases they formed no 

 large galls, but the exhausted leaves soon died; 

 and now, many limbs are entirely devoid of 

 leaves for a foot or two near the end, a few 

 young leaves still struggling into existence from 

 the buds near the tip. The young coccus is quite 

 an active traveller for this variety of insect. I saw 

 the young leaves densely populated, on side branch- 

 es of the vines, when no parent gulls were within 

 ten or twelve feet of them. When two or more 

 young coccus happen to locate close together, the 

 two original galls blend into one oblong perfect 

 one. But this can only occur, as I have observed 

 a thousand times, when the coccus are not so nu- 

 merous as to be closely clustered together on all 

 sides. A single leaf is not often able to form more 

 than about 5U0 galls. When it much exceeds this, 

 nature_jields as before observed, and the insect by 

 its excessive multiplication proves its own destruc- 

 tion in the destruction of the plant. 



The tendrils, leaf stalks and tender branches, are 

 not exempt from the attacks of these insects. I 

 have now before me a number of limbs, embracing 

 two or three feet of the end of the vine, all covered 

 with fleshy wart-like galls, usually elongated length- 

 wise of the limb, others quite similar to those on 

 the leaves, with such difi'erences as situation esta- 

 blishes. On the leaf the gall is formed by the irri- 

 tated surface receding away from the insect, and 

 an abnormal cell-growth on the opposite side of the 

 leaf; while in the limb the very necessity of the 

 ease prompts a modification of this same effort on 

 the part of the vine ; the bark thickens around the 

 coccus, and forms a juicy, irregular wart, with the 

 gall usually open on the top, the sides being much 

 thicker than the leaf gall. From a close microsco- 

 pic examination, I am not able to detect any essen- 

 tial difi'erence in the insects themselves, as found 

 on the leaf, stem, tendrils or limb. The tendril is 

 more pliable than the limb, and here we see, as in 

 the leaf, the same abnormal growth and thickening 

 on the opposite side, whence it curves partly around 

 the insect. The cavities in these galls are not so 

 roomy as in those on the leaf, and we find fewer 

 eggs and young ; but the eggs and young, as well 

 as the parents, are in all respects similar to those 

 on the leaf 



Furthermore, from my observations, I am of the 

 opinion, that the few that escape from their enemies 

 on the tendrils and limbs late in the fall pa.ss the 

 winter in the g:ill, and are ready for operations on 

 the tender leaves in the spring. The limbs, espe- 



cially where the leaves have died and fallen off, are 

 almost covered with black, rough scars. This is 

 produced by the insect from some cause failing to 

 develop, the succulent, warty limb-gall either fall- 

 ing off accidentally or being destroyed by its natu- 

 ral enemies. For on the limb, it will be observed, 

 as well as on the leaf, that the presence of the in- 

 sect is necessary to the continuance of the gall; 

 and as soon as the insect is outside, the gall ceases 

 to grow; and if already fully developed, partly 

 opens as the vine attempts to restore the injured 

 part, and, as a natural consequence, leaves a black- 

 ened scar. 



Mr. Walsh, in the Practical Entomologist 

 (Vol. I, p. 112), gives it as his opinion, that the 

 galls on the tendrils are made by a different species 

 of bark-lice. 2 Those that I have always observed 

 on the tendrils and tender limbs, for two or three 

 years past, appear to agree with his account of his 

 supposed new species. If they do, I am inclined 

 to think that, after studying them three or four 

 years, he will refer them to the .same species; for 

 if he constructs a .species for those on the tendrils, 

 he must also construct another for those on the 

 limbs. He gives it as his opinion that they will 

 not prove injurious, and may perhaps be beneficial. 

 I sincerely hope he may be correct, but fear that 

 they will prove to be to the grape what the apple 

 bark-louse is to the apple tree — its most deleterious 

 enemy; and if I were buying I would no more 

 think of purchasing grape vines from a nursery 

 with the grape-leaf coccus, than I would apple 

 trees from one having the apple bark-louse. My 

 reasons for this are not without foundation. Since 

 I first knew them, they have held right on through 

 every adversity with a steady increase, and to-day 

 are much worse than I ever saw them before. They 

 endure the most severe winter weather without pro- 

 tection. 



The most important question practically is, what 

 are the agents that may be brought to bear against 

 them, to hold them in check? 



They resolve themselves into two : 



First. Man — he can do something, though the 

 smallest part of the work, by gathering up and 

 burning all his trimmings, in the fall, winter or 

 spring, when this work is done, and by raking up 

 tlie leaves and burning them. For it is not im- 

 possible that some eggs may be in the leaf galls, 

 late in the fall, after the weather becomes too cold 

 for hatching them; (though last fall I made close 

 search on the 1st of October, and found all empty 

 that I examined;^) any thus passing the winter in 

 the dead leaf on the ground would hatch in the 

 spring, and the young insect, in its wanderings in 

 quest of food, might reach the vine stalk and then 

 the young leaf. 



Si-cond. Insect Enemies. These are far the most 

 efficient agents; and it is one of the most interesting 

 themes to witness the strife for life upon a grape leaf. 

 I have observed some half dozen or more enemies, 

 some of them very efficient. Mr. Walsh speaks of 

 an orange colored larva from which he bred a small 

 fly. lie gives no account of the fly except its sine. 



