126 THE entobiologist's record. 



ling), their n)il>/ nat)(ral foml-plant, although in confinement they will 

 eat freely the leaves of HctMla alha and //. (/lutindsa. On emer- 

 gence, which usually takes place during the second, or, at latest, the 

 third week in July, the young larva is dark ash-coloured, the incisions 

 of the segments being indicated by two minute orange streaks, etc. 

 At the end of October it hybernates for the winter, and, in April, begins 

 to feed again. In June, it undergoes its final moult, having then 

 completed the first year of its existence, and is full-fed at the end of 

 August, when it retires towards the roots of the ling, and spins a dark 

 brown oblong tough cocoon, which it attaches to the stems and twigs 

 of the heather, ling, sedges, and other herbage, and the cocoons are 

 to bo found by separating the herbage down to the roots. Within 

 this cocoon the larva changes to a short, obese dark brown pupa, in 

 which state it continues throughout the winter until the following 

 May or June, Avhen, having completed the second year of its existence, 

 it appears in the perfect state." 



Of Bomhij.v qiiercns, Newman writes : — " The male flies rapidly, both 

 by broad daylight and after sunset, at the latter end of July and 

 beginning of August. The female is very lethargic, and rarely moves 

 prior to impregnation, and afterwards flies heavily and languidly, and 

 never to the same extent or so rapidily as the male. The female ovi- 

 posits like callunac, and the young larvte emerge towards the end of 

 August. They feed on Iluhus frnctimmn (bramble), Cratacf/us o.njacantha 

 (whitethorn), Prnnm spiiuisa (blackthorn), Ci/tisus scoparius (broom), 

 and other shrubs ; and towards the end of October they hybernate, 

 and appear again in the spring ; they again commence feeding, and 

 are full-fed in May, and then spin a compact oval yellow cocoon, 

 and turn to a dark brown, but not a shining pupa, from which the 

 moth emerges in July." 



The differentiation of the two allied species, />'. qiuo-nis and B. 

 calhniac, is then set forth in the following manner : — " All differences 

 in natural history are attractive in proportion to their amount, 

 and valuable in proportion to their constancy. In pairs of species the 

 amount of difference decreases as the individuals approach ma- 

 turity. As regards those under consideration the differences 

 are: — 1. In time of appearance. — B, callunae appears in May 

 and B. quercm in July. 2. In the time occupied in arriving at 

 MATURITY. — B. quercus takes but one year, and P>. callunac, two. 

 3. In food. — /). qxwrcm feeds on whitethorn, blackthorn and broom, 

 and B. callunac, only on ling. 4. In the ornAiMentation of the 

 toung larvae. — B. quercus has a dorsal series of lozenge-shaped 

 markings, white and orange, and B. callunae a dorsal series of triangle 

 shaped spots, orange only. 5. In pupation. — B. quercus forms a 

 small yellow cocoon, and B. callunae a large brown cocoon. 

 6. In the colour of the imago. — The wing-rays of 7>. quercus in 

 passing through the pale band of the wing assume its colour, and in 

 B. callunae they are darker than the band. In B. quercus, the lower 

 extremity of the band has a direction towards the abdomen ; in 

 B. callunae the direction is toAvards the anal angle of the wing, and 

 this holds good, both in the fore and hind-wings, more especially the 

 latter. The males of B. quercus are of a ferruginous brown colour, and 

 thoseof ii'. callunaeoi umber brown. 7. In size. -5. quercus is the smaller 

 of the two insects." I think there cannot be any doubt in the mind 



