140 THE ENTOMOLOGIST. 



continued on the preceding segment ; the white wedge- 

 shaped marks, ten in number, form a striking medio-dorsal 

 series ; the ventral surface is smoky black, and the legs and 

 claspers are rust-coloured. In the spring they again appear, 

 and commence feeding ; after an additional moult the dorsal 

 ornamentation has entirely disappeared. The head is now 

 purplish black ; the body velvety black, but densely covered 

 with a short pile of an umber-brown tint, and this again is 

 interspersed with longer hairs ; these especially form two in- 

 distinct and ill-defined tufts, on each side of each segment, 

 pointing outwards ; these hairs are gray at the extremities : 

 the velvety black ground colour shows conspicuously, at the 

 incisions of the segments, as so many transverse black bands, 

 on the posterior margin of each of which is a small white 

 spot ; these white spots forming together a medio-dorsal series, 

 but neither the black bands nor the white spots are observable 

 when the larva is at rest, and only appear when it is in 

 active motion, or when rolled in a ring ; on each side of the 

 3rd and 4th segments is a somewhat crescentic white mark- 

 ing, decorated with an orange dot in the middle ; a row of 

 smaller white spots form a lateral series just above the spi- 

 racles, and each of these is accompanied by minute orange 

 markings ; the spiracles are pure white ; the ventral surface 

 is smoke-coloured, and the legs and claspers pitchy black. It 

 is full-fed in May, and then, retiring towards the ground, 

 spins a compact, oval, yellow cocoon, and turns to a dark 

 brown and smooth, but not shining, pupa, from which the 

 moth emerges in July, — Edward Newman. 



Differentiaiio)i of the two allied Species, Boinhyx Cal- 

 lun<B and Bomhyx Quercus. — All differences in Natural His- 

 tory are attractive in proportion to their amount, valuable in 

 proportion to their constancy. In pairs of species the amount 

 of difference decreases as the individuals approach maturity. 

 As regards the pair of species now under consideration, the 

 differences are — 1st, in time of appearance ; B. Callunae ap- 

 pears in May, B. Quercus in July : 2nd, in the time occu- 

 pied in arriving at maturity ; B. Quercus takes but one year, 

 B. Calluna) two : 3rd, in food ; B. Quercus feeds on white- 

 thorn, blackthorn and broom, B. Callunae only on ling : 4th, 

 in ornamentation of the young larva ; B. Quercus has a dor- 

 sal series of lozenge-shaped markings white and orange, B. 



