THE ENTOMOLOGIST. 



No. 63.] MARCH, M.DCCC.LXIX. [Price 6d. 



A Life-history of Fennna fuliginosa? — This little Ten- 

 Ihvedinideous larva is a leaf-rainev, and, like Fenusa purnila 

 the bramble-feeder, it is double-brooded : the first brood of 

 larvae are to be found feeding in the leaves of Betula alba 

 (the birch) about the 12th of June, the parent fly preferring 

 to deposit her eggs on a variety of the birch whose leaves 

 have a flannelly or woolly feel when slightly pressed between 

 the fingers. The newly-born caterpillar commences life by 

 eating its way into the interior of the leaf; it then throws 

 itself on its back, a favourite mode of feeding adopted by the 

 leaf-mining Tenthredo-larva^, and makes a minute circular 

 blotch in the birch-leaf, of a pale greenish colour ; at times 

 only one egg is deposited, at others there are two, three, four 

 or five, and occasionally a leaf may be met with containing 

 as many as eight or even nine of these little blotches scat- 

 tered about its upper surface : the contained larva has twenty- 

 two legs, six of them being thoracical, fourteen ventral and 

 two anal ; the fifth and thirteenth segments are not provided 

 with legs of any kind. There is no emission of fluid from 

 the pores of its body, nor are the exuviae expelled from the 

 mine ; the head and eye-spots are pale brown, the body 

 white, the dorsal vessel dull green, the thoracic legs white 

 encircled with pale brown rings, and the ventral surface of 

 the 2nd segment is adorned with a black dumb-bell-shaped 

 plate ; the two following segments each possess a central 

 black dot ; the ventral and anal legs are white, the latter 

 without the partly encircling band which is so commonly ob- 

 served on the anal legs of mining Tenthredo-larvae. In a few 

 days some of the liltle blotches may still be observed occu- 

 pying an isolated position, but the major portion are found 

 to be more or less confluent ; and ultimately the larvae, by 

 consuming all the parenchyma between their respective 

 mines, convert the whole of them into one general blotch, 



VOL. IV. Q 



