THE FARMERS' REGISTER. 



327 



ed round the trunks of the trees. Worn out 

 Indian rubber shoes, which are worth little or no- 

 thing for any other purpose, can be put to this 

 use. This plan has been tried by a few persons 

 m the vicinity of Boston, some of whom speak 

 favorably of it. It has been suggested that the 

 melted rubber might be applied immediately to 

 the bark wiihout injuring the trees. A little coni- 

 cal mound of sand surrounding the base of the 

 tree is found to be impassable to the moths, so 

 long as the sand remains dry ; but they easily pass 

 over it when the sand is wet, and they come out 

 of the ground in wet, as often as in dry weather. 

 Some attempts have been made to destroy the 

 canker-worms after they were hatched from the 

 eggs, and were dispersed over the leaves of ihe 

 trees. It is said that some persons have saved 

 their trees from these insects by Ireely dusting air- 

 slacked lime over them while the leaves were weV 

 with dew. Showering the trees with mixtures 

 that are found useful to destroy other insects has 

 been tried by a few, and although attended with 

 a good deal of trouble and expense, it may be 

 worth our while to apply such remedies upon 

 small and choice trees. Mr. David Haggerston, 

 of Waterlon, Ms., has used for this ptiTpose a 

 mixture of water and oil-soap, (an article to be 

 procured from the manufactories where whale oil 

 is purified,) in the proportion of one pound of the 

 8oap to seven gallons of water ; and he states that 

 this liquor, when thrown on the trees with a gar- 

 den engine, will destroy the canker-worm "and 

 many other msecis, without injuring the foliage or 

 the fruit. Jarring or shaking the limbs of'^the 

 trees will disturb the canker-worms, and cause 

 many of them to spin down, when their threads 

 may be broken off with a pole ; and if the trouahs 

 around the trees are at the same time replenished 

 with oil, or the tar is again applied, the insects I 

 will be caught in their attempts to creep up the 

 trunks. In the same way, also, those that are 

 coming down the trunks to go into the ^rround 

 will be caught and killed. I( greater pains were 

 to be taken to destroy the insects in the caterpillar 

 slate, their numbers would soon greatly diminish. 

 Even after they have left the trees, have o-one 

 into the ground, and have changed their Ibrms, 

 they are not wholly beyond the reach of means 

 lor destroying them. One person told me that his 

 swine, which he was in the habit of turnint^ into 

 his orchard in the autumn, rooted up and killed 

 great numbers of the chrysalids of the canker- 

 worms. Some persons have recommended die/- 

 ging or ploughing under the trees in autumn, wifh 

 the hope of crushing some of the chrysalids by so 

 doing, and of exposing others to perish with the 

 cold of the following winter. If hogs are then 

 allowed to go among the trees, and a few grains 

 01 corn are scattered on the loosened soil, these 

 animals will eat many of the chrysalids as well 

 as the corn.^and will crush others with their feet, 

 ivir. t>. F. i^owler* thinks it better to ditr round 

 the trees in July, while the shells of thp°insects 

 are soft and tender. He and Mr. John Kenrick, 

 ot rsewton, Mass., advise us to remove the soil 

 to the distance of four or five feet from the trunk 

 01 the trees, and to the depth of six inches, to 



England l^tl o?Tune 2' Sl^l V'' ''''' ^"'^i ""iT 

 remarks by Mr. Fowler ' ' ' '''"'' ^^^""^^^^ 



cart It away and replace it with an equal quantity 

 of compost or rich earth. In this way, many of 

 the insects will be removed also ; but, unless the 

 earth thus carried away, is thrown into some 

 pond hole, and left covered with water, many of 

 the insects contained in it will undergo their trans- 

 formations, and come out alive the iText year. 



Canker-worms are subject to the attack's of 

 many enemies. Great numbers of them are de- 

 voured by several kinds of birds, which live al- 

 most entirely upon them during their season 

 They are also eaten by a very large and splendid 

 ground-beetle, {'Cahsoma scrutator,) that appears 

 about the time when these insects begin to leave 

 the trees. These beetles do not fly. but they run 

 about in the grass after the canker-worms, and 

 even mount upon the trunks of the trees to seize 

 them as they come down. The latter are also 

 stung by a four-winged ichneumon-fly. which de- 

 posiles an egg in every canker-worm thus wound- 

 ed. From the egg ia hatched a little macrcrot 

 that preys on the fatty substance of the canker- 

 worm, and weakens it so much that it is unable to 

 go through its future transformations. I have 

 seen one of these flies sting several canker-worms 

 in succession, and swarms of them may be ob- 

 served around the trees as long as the canker- 

 worms remain. Their services, therefore are 

 doubtless very considerable. Among a laro'e num- 

 ber of canker-worms, taken promiscuously from 

 various trees, I found that nearly one-third of the 

 whole were unable to finish their transformations 

 because they had been attacked by internal ene- 

 mies of another kind. These were little matro-ots 

 that lived singly within the bodies of the caTker- 

 j worms, till the latter died from weakness : after 

 I which the maggots underwent a chancre, and 

 I finally came out of the bodies of their victims in 

 the form of small two- winged cuckoo- flies, belonf^- 

 ing to t^he genus Tachina. Mr. E. C. Herrick, of 

 INew Haven, Connecticut, has made the interest- 

 ing discovery that the eggs of the canker-worm 

 moth are pierced by a tiny four-winged fly, a spe- 

 cies of Platygaster, which goes from eg^r to eo'o' 

 and drops in each of them one of her own e^^s 

 Sometimes every canker-worm eacr in a clulTer 

 will be found to have been thus punctured and 

 seeded for a future harvest of the Platy^aster. 

 Ihe young of this Platygaster is an exceedin^^ly 

 minute maggot, hatched within the canker-wo*rrn 

 egg, the shell of which, though only one thirtieth 

 ol an inch long, serves for its'habitation, and the 

 contents for its food, till it is fully grown ; after 

 which it becomes a chrysalis within the same 

 shell, and in due time comes out n Platy9;aster 

 fly, like Its parent. This last transformation Mr 

 Herrick found to take place towards the end of 

 J une, from eggs laid in November of the year be- 

 lore; and he thinks that the flies continue alive 

 through the summer, till the appearance of the 

 can.<er-worm moths in the autumn affords them 

 the opportunity of laying their eggs for another 

 brood. As these little parasites prevent the 

 hatching of the eggs wherein they are bred, and 

 as ihey seem to be very abundant, they must be 

 of great use in preventing the increase of the 

 canker-worm. Without doubt such wisely ap- 

 pointed means as these were once enough to keep 

 \yithin due bounds these noxious inspects; but 

 since our forests, their natural food, and our birds, 

 their greatest enemies, have disappeared before 



