Pear and Cherry Sawfly. 



343 



castings of skin, it loses its slug or tadpole form and assumes 

 the shape of an ordinary larva, of an orange yellow or 

 buff colour. After this change it crawls down the tree, or 

 falls, to the ground, and develops into a dark-coloured 

 chrysalis in a little cell made of earth, in which it remains 

 until the next spring, when it changes to a sawfly. 



The larvae of this sawfly are found upon the leaves of 

 fruit trees even as late as October. Some specimens were 

 sent to the Board of Agriculture on the 2nd October last. 

 It is evident, therefore, that there are two broods in a summer, 

 at least when the conditions are favourable. Unlike most 

 other larvae and caterpillars, this slugworm eats away the 

 leaves from their centres and not from the outsides ; it clears 

 away the parenchyma, or soft tissue, between the ribs and 

 nerves, leaving them bare as the framework of a parasol. 

 Air. Cameron, in his Monograph of British Phytophagous 

 Hymenoptera, says that the slugworms eat only the epidermis. 

 At first the leaf g*ets eaten in patches, but ultimately eve^y 

 particle of green is devoured, and the leaf finally falls to the 

 ground. When these larvae are present in great numbers the 

 noise they make in feeding, Mr. Cameron adds, is said to 

 resemble the falling of drops of rain on the leaves. They are 

 very sluggish, and their sluggishness is only surpassed by 

 their voracity. A severe infestation of them entirely prevents 

 the production of fruit, and even a slight attack has a marked 

 effect on the crop of pears, which cannot come to perfection 

 if the leafage of the tree is injured. 



This insect, or a species of sawfly closely resembling it, is 

 .said to do much harm to pear and cherry trees in America 

 It is there styled Selaudria cerasi. As early as 1797, according 

 to Harris, the larvae of this sawfly caused great injury. " Small 

 trees," he says, "were covered with them, and their foliage 

 entirely destroyed, and even the air, by passing through the 

 trees, became charged with a disagreeable and sickening 

 odour given out by these slimy creatures." In California it 

 is often very troublesome, especially to pear trees. Protessor 

 Saunders states that in 1874 this sawfly was unusualiv abun- 

 dant in Ontario, in many ca^es destroying the iohage so 



