OF THE SAW-FLIES (TENTHREDINID.E). 131 



of the smallest known species of saw-flies (Fenusa pumila) 

 measuring only one-eighth of an inch in length, and about 

 a quarter of an inch in the expanse of the fore wings. The 

 presence of these little parasites on the leaves has a decided 

 ill effect upon the plants on which they abound, as I 

 observed some which, in consequence of this visitation, did 

 not produce a proper crop of fruit for two or three years. 



A second brood of this larva is to be met with in Sep- 

 tember and October, and is so abundant in the leaves of the 

 bramble, that, as Mr. Wailes has remarked in the Zoologist, 

 1856, p. 5074, " every Micro-Lepidopterist must have 

 noticed it;" from these proceed the perfect insects in the 

 following summer, which deposit their eggs on the leaves of 

 the raspberry or bramble. 



About the beginning of the month of August, the upper 

 surface of the leaves of pear, cherry and plum trees may be 

 observed to be infested with black shiny looking objects, 

 which, when disencumbered of their viscid coating (which 

 has a strong scent, something like that of bad red-ink), are 

 discovered to be the larva of a saw-fly (Selandria atra, 

 Stephens). They vary in length from a quarter to half an 

 inch, are of an elongate pear-shape, and their general ap- 

 pearance is not unlike a drop of resinous matter, such as 

 that which issues from the plum-tree ; their ill effects are 

 soon perceived upon the trees attacked by them, the upper 

 surface of the leaves being eaten off in patches, and the 

 remainder soon presenting the appearance of having been 

 scorched. In hot weather, where they abound, the noise of 

 their operations on the leaves may be heard like drops of 

 rain falling upon the leaves. When full grown, the larva 

 falls to the earth, and undergoes its changes to the perfect fly, 

 which appears in the following July. Having reared the 



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