THE b;ntomologist. 139 



brown. The larva has six thoracic, fourteen ventral and two 

 anal legs, amounting to twenty-two in all : its head is shining 

 brown, darker at the sides ; the shining dark brown shield on 

 the back of the 2nd segment, and the narrow dark-coloured 

 shield on the same surface of the 3rd segment, are divided 

 down their centres by the dorsal line ; the ventral sur- 

 face of the 2nd segment is decorated with a largish 

 shining black plate ; the 3rd and 4th segments have each a 

 little shining black plate on them : the body is white, and 

 the thoracic legs are circled with pale brown rings ; ventral 

 legs white, the two anal legs being partly surrounded by a 

 dark brown band broader at each of its extremities ; the 5th 

 and 13th segments are entirely without legs. The larva, in 

 order to keep its mine tolerably free from " frass," resorts to 

 the curious expedient of loosening the upper and lower 

 cuticle of the leaf ; at its edge, and through the hole thus 

 formed, it ejects its "frass" sideways out of its mine. During 

 its lifetime the larva casts its skin several times, and by the 

 time the fourth moult takes place it has robbed the leaf of a 

 considerable portion of its cellular tissue: at times it eats all 

 the parenchyma of the leaf, at others only about half of it is 

 consumed ; on some occasions the larva makes its way along 

 one side of the midrib of the leaf, completely gutting that 

 part : it then turns round and devours a portion, if not the 

 whole, of the parenchyma situate on the other side of the 

 midrib, the whole mined part of the leaf turning a dingy 

 brown. At length, having arrived at maturity, the larva 

 moults for the last time, and, like all the larva? of this order 

 of insects, after its last moulting it looks a very different 

 creature ; its mouth is pale brown, with darker markings ; 

 eye-spots black ; head and body yellowish white, the mark- 

 ings on its pectoral and anal legs being of a very faint 

 brownish tinge ; its dorsal line is pale orange-yellow ante- 

 riorly, and green at its posterior ; ultimately, however, the 

 valves of the dorsal vessel discharge their contents, and the 

 dorsal line is then lost to view. When about to enter upon 

 its pupation the larva either bites a hole in the under side of 

 its mine and descends to the ground to pupize, or else forms 

 a circular-shaped cocoon within the mine itself: when the 

 larva feeds out-of-doors on the sallow-bushes it sometimes 

 forms its cocoon inside the mined leaf, but in the majority of 



