102 iMay, 



pupa, I visited the spot on June 9th last, and from larvae, about 

 full-fed, chosen out of the large number then collected on alder 

 (^Alnus gliitinosa), made the following description on June lOth : — 



LARVA. 



Length, when iiioderatelj sti-etched, 10 Dim. Greatest breadth, -i'o mm. Head 

 highly polished, brownisli-black, rather narrower than prolhorax; ocelli indistinctly 

 paler. Frothorax with the anterior margin whitish in front of the j)la.te, wiiich is 

 large, highly polished, brownish-blaek, bisected by a narrow whitish line. The 

 thoracic and abdominal segments together form a mass which is stout in the middle, 

 and tapers off gradually towards the head, and abruptly near the anal extremity ; 

 their colour, which is greyish-white laterally, is pale bluish -grey dorsally, with the 

 pulsating vessel showing through the skin as a central ill-defined darker bluish-grey 

 line, tikin smooth, but not glossy. Tubercles large and conspicuous, dusky-brown, 

 polished. Spiracles small, circular, brownish-black, polished. Penultimate ab- 

 dominal segment dorsally with a small blackish-brown, polished, elliptical-oval, 

 central plate. Anal segment with a large, polished, brownish-black, dorsal plate, 

 emitting a few rather long pale brownish hairs, and with a small, polished, dusky- 

 brown, elliptical-oval plate on each side above the clasper. Hairs pale brown, but 

 few, and mostly short and inconspicuous. Veidral surface greyish-white, concolorous 

 with the sides, the segmental interstices, which mostly show darker, being pale 

 bluish-grey, concolorous with the dorsal area. Legs highly polished, externally 

 brownish-black, narrowly ringed with whitish at the joints, internally paler. Pro- 

 legs greyish-white, with the extremities brown, and with two dusky-brown bars 

 across each side externally. 



None of the adult larvae showed any variation worthy of mention. Yarious 

 young individuals, of which the smallest was only 6 mm. in length when at rest, 

 were examined, and all exactly resembled the full-fed ones, except that they were 

 somewhat paler, the ground colour dorsally being greyish-white instead of pale 

 bluish-grey, and proportionally lighter elsewhere. 



The larva only frequents and feeds on the youngest and most 

 tender leaves on the alder bushes. Having selected one such leaf 

 at the end of a shoot, it takes up its position on the upper surface 

 along the midrib, and by spinning white silk threads across from side 

 to side, it gradually, owing to the contraction of the silk, draws the 

 two sides of the leaf together over itself like a tent, and as soon as 

 the margins are sufficiently close, it unites them firmly together 

 throughout their length with strands of white silk, the leaf, when the 

 process is complete, somewhat resembling a very short and broad 

 pea-pod. The larva lives inside the domicile thus formed, and feeds 

 on the anterior portion of the inhabited leaf, gradually eating it away 

 from the apex downwards. When an appreciable part, often amount- 

 ing to about one-half, of the leaf has been devoured, so that the 



