POEOILOOAMPA POPULI. 469 



eggs as laid singly, and Bacot says that the similarity of the eggs to 

 those of Bombyx mori is very striking, and they appear to be laid in 

 the same scattered fashion. Eobertson obtained a female from a 

 Cheltenham pupa on December 6th, 1898, which laid most of its 

 eggs the following day. Eggs are noted as hatching April 19th, 1865 

 (Todd), April 14th, 1890, at Brentwood (Burrows), March 26th, 1880, 

 April 14th, 1890 (Bower), February 3rd-14th, 1894 (Studd), April 

 20th, 1899 (Bacot), middle of February, 1895 (Woodforde). 



Ovum. — The eggs are flat, roughly rectangular in shape, with a 

 shallow depression on the upper surface ; the micropylar end squared 

 and slightly thicker than its nadir which is somewhat rounded. To 

 the naked eye, the egg looks dark brown with the micropylar end 

 whitish and Avith a dark micropylar point. The egg has no covering 

 of scales. Under a lens the ground colour is seen to be white, this 

 tint being especially noticeable around the sides of the egg ; the upper 

 surface is almost covered with irregular, dark grey, and black, polygonal 

 cells, usually in patches, and with a distinct opalescent appearance, 

 the proportion of grey and black varying greatly ; the sides are 

 irregularly and less thickly marked with dark grey and black blotches 

 made up of similar polygonal cells. Some eggs are almost devoid of 

 these lateral blotches, on the other hand some are strongly marked 

 with them, the black predominating. The surface is shiny, finely 

 reticulated with very shallow polygonal cells (? pits), which give one 

 the idea that the markings are really made up of groups of such 

 cells ; the reticulation is very bright and shiny. The micropylar end is 

 white, with a comparatively large micropylar depression of a dark brown 

 hue, finely reticulated, the micropyle proper consisting of a small black 

 depression at the centre of the larger depression. The nadir of the 

 micropyle is characterised by a round whitish central blotch, surrounded 

 by the same type of markings as those on the upper surface. The 

 larva? , when they escape, make a large irregular hole at the micropylar 

 end of the egg, in order to leave it [Description made October 27th, 

 1897, under a two-thirds lens from ova laid by a ? on October 21st, and 

 sent by Mr. Head of Scarborough.] Bacot describes the egg as a flattened 

 oval, slightly depressed on exposed face ; the shell thick, opaque- 

 looking, whitish-grey, much mottled with black and brown ; a large 

 round dark spot at micropylar end ; the surface covered with an irregular 

 hexagonal reticulation, the mottling due to the hexagons being 

 differently coloured (and giving the idea of the pattern being mapped 

 in Tunbridge ware). 



Habits of larva. — Eggs laid in November usually hatch from the 

 end of March to the middle of April, and the young larva? feed up 

 readily on oak and poplar. Eggs in Todd's possession, hatched on April 

 19th, 1865, the larva? changed skin only once up to May 6th, when 

 a second change took place. When twenty days old they were greyish a 

 just as if sprinkled over with the dust of bran. At this time, he says, 

 the young larva? cling by their claspers to the stem of the food-plant, 

 and, when one moved, the others usually followed, and appeared to 

 keep close together. On May 16th a third exuviation took place, when 

 two conspicuous red spots appeared on the prothorax. The long white 

 fringe that hangs laterally over each side aids its close resemblance to 

 the branch on which it rests. The larva? changed skin again on May 

 23rd, and spun up from June 2nd-4th. When full-fed the larva rests 



