262 CEKASUS VULGAUIS. 



Mr. Loudon ri'murks thai, '''riicse holes, by adiuitliii^ water, accelerate the 

 decay ot" the heart-wooil of the tree; but it is a mistake to suppose, as many do, 

 that the decay originates with the wood-jjccker, wlio gets the credit of making 

 the hles out of slie(>r misehiff. or for anuisrinent : the truth beiiiii. that decay 

 has eoinuienceil, and that hi' is only in search of his food, whicii consists ol the 

 larvic which liavc already begun to eat the wood of the tree.' 



Ami>n<r tlie insects whiidi inl'est the common cherry-tree are several species of 

 the ( Jc<inctrid;e, including the canker-worm, {l^lmhrfui rrnniln.') and numerous 

 wood-eatiiiu Iarva> (X ylophagitke.) The curculio, {^Uliijnrhd mis lunupliar,^ 

 noticed under ilu' head of " Insects, A:c.," in our article on tlie domestic culti- 

 vated |)hnn, is also known to be the cause of the warty excrescences fiuiid on 

 the small branches of the cherry, from which circumstance, it was called by 

 Professor Feck, Ji/iijnr/nfiu/s ccrusi, the cherry-weevil. These excresccin:es, 

 which serve as the residence of the larva;, are known to be produced by ilie 

 punctures made in the tree by the beetles; and, according to Peck, "the s;|t is 

 diverted from its regular course, and is absorbed entirely by the bark, whicli is 

 very much increased in thickness; the cuticle bursts, the swelling becomes irreg- 

 ular, and is formed into black lumps, with a cracked, uneven, granulated sur- 

 face. The wood, besides being deprived of its nutriment, is very nmcli com- 

 pressed, and the branch above the tumour perishes." The same remedies wil 

 apply in the present case as those recommended for the excrescences found on 

 the domestic cultivated plum-tree. 



But by far the most pernicious enemy to the common cherry-tree, is the slug- 

 fly, Blennocani pa ccrasi, of Harris. He describes the perfect insect, in his 

 ' Report," as being "of a glossy black colour, except the two first pairs of legs, 

 which are dirty yellow or clay-coloured, with blackish thighs, and the hind-legs, 

 which are dull black, with clay-coloured knees, "^riie wings are somewhat con- 

 vex, and rumpled or uneven on the upper side, like the wings of the saw-flies 

 generally. They are transparent, reflecting the changeable colours of the rain- 

 bow, and have a smoky tinge, forming a cloud, or broad band across the middle 

 of the first pair; the veins are brownish. The body of the female measures 

 rather more than one fifth of an inch in length; that of the m^\e is smaller. In 

 the year 1828, I observed these saw-flies, on cherry and plum-trees, on the lOtli 

 of May ; but they usually appear towards the end of May or early in June. 

 Soon afterwards some of them begin to lay their eggs, and all of them finish this 

 business and disappear, within tlie space of three weeks. Their eggs are placed, 

 singly, within little semicircular incisions through the skin of the leaf, and gene^ 

 rally on the lower side of it. ***** On the fourteenth day afterwards, 

 the eggs begin to hatch, and the young slug-worms continue to come forth from 

 the .5th of June to the 20th of July, according as the flies have appeared early or 

 late in the spring. At first, the slugs are white; but a slimy matter soon oozes 

 out of their skin and covers their backs with an olive-coloured, sticky coat. 

 They have twenty very short legs, or a pair under each segment of the body, 

 except the fourth and the last. The largest slugs are about nine- twentieths ot 

 an inch in length, when fully grown. The head, of a dark-chesnut colour, is 

 small, and is entirely concealed under the fore-part of the body. They are larg- 

 est before, and taper behind, and in form somewhat resemble minute tadpoles. 

 They have the faculty of swelling out the fore part of the body, and generally 

 rest with the tail a little turned up. These disgusting slugs live mostly on the 

 upper sides of the leaves of the pear and cherry-trees, and eat away the substance 

 thereof, leaving only the veins and the skin beneath, untouched. Sometimes 

 twenty or thirty of them may be seen on a single leaf; and, in the year 1797, 

 tliey were so abundant in some parts of Massachusetts, that small trees were 

 covered with them, and the foliage entirely destroyed; and even the air, by 



