560 BRITISH LEPIDOPTEKA. 



leaves of low plants and in cracks of walls at Namur (Lambillion) , 

 in the angle formed by the coping stone with the bricks of a wall, also 

 in angles formed by the upright and cross pales of a wooden fence (Sich). 

 Horton observes that he once found two co:oons, linked together, 

 hanging on a reed, near the sea at Looe. 



Cocoon. — The cocoon is about 24mm. -30mm. in length, and 10mm.- 

 12mm. in width. It consists of a loose outer web of whitish silk, enclosing 

 a closely spun, strong, oval, inner cocoon, thickly sprinkled (when made 

 by healthy and well-fed larvae) with particles of a yellow powder. This 

 powder consists of very minute crystals formed from a substance 

 secreted by the malpighian tubules and discharged from the anus of 

 the larva. The yellow colour is said to be probably an unstable 

 organic pigment, as it is destroyed at a comparatively low temperature, 

 leaving the crystals unaltered. The crystals themselves have been 

 shown to be composed of calcium carbonate in the form of aragonite. 

 Harrison has observed that the cocoons, instead of being felted like 

 those of Lasiocampa quercus, are more or less thickly coated with a 

 pollen-like dust, but this latter is absent in the cocoons spun by poorly 

 fed larvas. Bossier describes the yellow material as "a sharply 

 irritating dust." Bacot says that the cocoon of the female is 2mm.- 

 3mm. wider than that of the male ; the outline of the pupa sometimes 

 easily seen through the material ; the loose, flimsy, outer structure of 

 irregular size and shape, in which the cocoon proper is placed, is used 

 to attach the latter to the object on or among which the larva spins. 



Double and triple cocoons. — Ingall notes that on July 3rd, 1836, 

 he found a cocoon which contained two pupae, male and female. 

 Prideaux records that in 1888 two larva? spun a common cocoon from 

 which the moths emerged in no way malformed. Simes notices two 

 cocoons that contained respectively two and three pupae, and 

 Montgomery observes that he has sometimes found two and even three 

 pupae in one cocoon in confinement. Mansbridge records a cocoon 

 which contained two pupae, and observed that though the imagines had 

 emerged from the pupa-cases they were unable to get out of the cocoon ; 

 the latter is described as consisting of a single cavity partially divided. 



Pupa. — $ 14mm.-14-75mm. in length, 4-75mm. in width (at 

 broadest part). ? 17 , 25mm.-21-2mm.inlength,8mm.inwidth(at end of 

 wing-cases = the widest part) . Female pupa : Laterally the outline is that 

 of a bow — straight along the ventral area, arched dorsally from the some- 

 what rounded anus upwards to the large 4th abdominal segment, and 

 more rapidly to the bluntly rounded head from the 2nd abdominal 

 segment. Colour black, or very dark brown; smooth; wings, legs, 

 antennas, and face-parts, also 8th and 9th abdominal segments, shiny ; 

 remaining surface dull, for the most part covered with fine hairs, 

 which entangle the yellow particles of aragonite from the cocoon and 

 some of the larval hairs ; the dorsum of anal segment prolonged, 

 projecting considerably beyond the anus, which is ventral ; the anal 

 armature consists of short, stout bristles, slightly knobbed at apices, 

 best developed and thickest at extremity, but covering altogether a large 

 portion of anal segment and running back to its margin dorsally ; the 

 position of anal orifice and sexual organs well and clearly marked ; the 

 spiracles are not remarkable, that on the 3rd abdominal segment just 

 shows at edge of hindwings ; the metathorax is very short, the meso- 

 thorax very long, the prothorax fairly large with a portion separated 



