THE PRACTICAL ENTOMOLOGIST. 



31 



lai'v:i3 to conditions unfavorable to their existence. 

 How much coulj be accomplished in this way? 



Then the free application of salt, lime and ashes, 

 in the fall, I have thought, might have much effect 

 to destroy insect larvae in the soil. Do you think 

 so 'f 



5tli. Eoerr/recns as a Harbor for Insects. — The 

 question has lately presented itself to my mind, how 

 far Evergreens, and especially Evergreen Hedges, 

 in and about orchards, may prove injurious, by 

 forming a sale harbor for insects in winter. I have 

 several thousand evergreens in and near my orchard, 

 and several thousand feet of very dense Norway 

 Spruce and Arbor Vitas hedges. These plants are, 

 of course, infested with insects peculiar to them- 

 selves. They are subject to Aphides and Borers 

 and Basket Worms. Do they also shelter the Cur- 

 culio,-the Codling Moth, and other insects destruc- 

 tive to fruit-trees? I should be glad to have some 

 precise information on this point. Evergreens and 

 hedges furnish protection to small birds, which of- 

 ten build their nests in them; but I fear the in- 

 sects are more numerous than the birds. 



6th. SpiJrrs and Wasps in the Orchard. — These 

 insects are very numerous in my orchard, and on 

 the fruit-trees and evergreens. I have been told 

 that the spiders attack the tender fruit-buds, and 

 opening fruit-blossoms, and devour the pistils and 

 the pollen. I have never seen anything of this. 

 Is it probable ? And what is the general influence 

 of the spider in the orchard? Wasps and Bees are 

 very injurious to ripening fruit. The Cantharides 

 and the Click-beetles make holes in every fruit in 

 the slightest degree decayed, and then the Wasps, 

 Hornets and Bees finish the work of destruction. 

 Do Spiders, Wasps, Bees or Hornets, destroy any 

 other insects injurious to fruit-trees? 

 PHiL.\nELpniA, Oct. 1866. 



Answers to the above, by B. D. W. 



1st. I have no personal knowledge that the Curculio 

 breeds in tlie cherry, but I see no reason to doubt the 

 fact. Dr. Trimble, who is better authority on this sub- 

 ject than any other man in this country, because he has 

 made Fruit InsucLs his special study for years, evidently 

 believes that it does; for he recommends outlying cher- 

 ry-trees, which cannot be properly attended to, to be cut 

 fliiwn. to prevent the propagation of the Curculio. (See 

 bis Fniit Insects, pp. 26 and 39.) And Dr. Fitch has 

 remarked upon the singular anomaly, that the cherry 

 and the thorn-apple, which are small fruits, hang upon 

 the tree and ripen when stung by the Curculio, "though 

 80 wounded, knotty and deformed, that the fruit is worth- 

 less;'' while on the other hand, the plum, the apple, the 

 pear and the peach, which are large fruits, wither under 

 the same circumstances, and fall to the ground. {Address 

 on. Curculio, Ac, ISOO, p. 18.) It is undoubtedly true, that 

 in very many apples and pears, the young larva of the 

 Curculio perishes prematurely; but that is evidently 

 because its natural food is stone-fruit, and it is only when 

 ?he cannot do any better, that the mother-insect has re- 

 course to pip-fruit. Indeed, it is only of late years, since 

 the Curculio has become so greatly multiplied, that it 

 has been observed to attack pip-fruit. Consequently, as 

 the Cherry is so closely allied to the Plum, that many 

 botanists class them under the same genus, and as the 

 Plum is the favorite food of this insect, we might reason- 

 ably infer a priori, even if we had no reliable evidence 

 on the subject, that the great bulk of the eggs deposited 

 in the Cherry will come to maturity, unless artificially 

 destroyed. 



But, if we allow this to be so, I do not see the force of 

 your reasoning, that we ought, on that account, to get rid 



of our Cherry-trees as soon as possible. It is a mistake to 

 suppose that one plum can only feed one Curculio. I have 

 repeatedly found several larvae in the same plum, and 

 Dr. Trimble has done the same. Hence, if one plum is 

 equal in bulk of flesh to four cherries, a plum-tree with 

 500 plums is capable of producing as many Curculios as 

 a cherry-tree with 2,000 cherries, supposing every fruit 

 to be stocked with Curculio eggs to its utmost capacity; 

 and your assumption that the Cherry can beat all other 

 trees at raising Curculios is probably incorrect. 



I may state here, that my belief is, that the Curculio 

 passes the winter in the perfect state, hybernating, as I 

 know many other snout-beetlos to do, in moss, under dead 

 bark, in tufts of old grass, Ac, and that those which 

 make their appearance in the spring to sting our early 

 fruit, are the individuals bred in the fruit, and sometimes 

 in the Black-knot,of the preceding year. Indeed Dr. Trim- 

 ble has actually found specimens hybernating under the 

 shingles of a roof, in the chinks of stone-walls, and under 

 the bark of an apple-tree. (Fruit Insects, p. 99.) The du- 

 ration of life among insects in the perfect state, has been 

 very generally under-estimated by entomologists. (See 

 some remarks on this subject in my Essay, Trans. III. State 

 Agr.Soc.Vfp.ilb.) As to Dr. Fitch's notion, that there is a 

 second brood of them, which is generated from eggs laid 

 towards the end of the summer in certain slits in pear- 

 twigs, I have little doubt that the egg-slits doubtingly re- 

 ferred to the Curculio by this author, were those of my 

 Chloroneura malefica or some other small Homopteroua in- 

 sect. (See Fitch, JV. Y. Rep. II, § 52, p. 33.) Dr. Trimble, 

 upon dissecting several Curculios which he had bred the 

 same season from fruit, found all their bodies to becmpty 

 of eggs; whereas, females captured in the spring contained 

 many eggs, one of them in particular twenty -five in num- 

 ber. {Fruit Insects, pp. 43 and 73.) 



2nd. What we call the "Bark-louse" or "Scale-insect" 

 of the Apple-tree and Pear-tree, is nothing but a scale 

 covering the eggs which are to hatch out next summer, 

 and is not seen until the middle of the autumn, because 

 previously to that time it had no existence, with the ex- 

 ception of the old ones of over a year's growth. There 

 are two perfectly distinct Bark-lice which infest the Ap- 

 ple-tree, and I will now point out the distinctions between 

 them. 



The OvsTER-snELL Bark-louse, {Aspidiotus conchiform- 

 is), which is represented of its natural size on the annex- 

 ed twig, a single individual being magnified to show its 



shape more clearly, is an imported Insect. It ia an aw- 

 ful pest in the orchard — has been gradually spreading 

 westward for many years — and has now reached my im- 

 mediate neighborhood. The scale here, according to all 

 authors, is composed of the body of the mother-louse dy- 

 ing and drying up in the autumn — is almost exactly the 

 color of the bark — and, when raised up with the point of 

 a pen-knife any time in the dead of the year, shows un- 

 derneath it many dozen minute, oval, milk-white eggs. 

 In the following summer these eggs will hatch out into 

 minute lice, which can scarcely be seen with the unas- 

 sisted eye, or if seen, would be mistaken for natural 

 specks in the bark, as they hardly move at all. 



Harris's Bark-louse, {Coccus? Sarrisii, Walsh), which 

 is exhibited in the annexed cut, in the same manner as 



the preceding, is a Native American Insect. I have no- 

 ticed it for many years on Crab-trees, and in small num- 

 bers on apple-trees, but never, until 1866, found it to 

 swarm on any Apple-tree so as to be dangerous, and then 

 only in the case of a single tree in my own garden. The 

 scale here ia supposed by Harris to be construotsd In 



