RURALIS BETUL.E. 



313 



it distributed throughout gardens and orchards, occurring sometimes 

 in abundance. In its wilder haunts in central Europe, it appears to 

 be not unusual to find it in the same localities as Strymon pruni, the 

 larvae feeding on the same bushes, but those of Ruralis betulae later than 

 those of S. pruni, in fact, the larvae of the latter are usually in their adult 

 stadia when those of the former are quite tiny. The wilder situations, 

 however, in which it is found are very varied, but it appears especially 

 to love the lower alpine valleys, where the turbulent glacier streams 

 rush through the wooded valley slopes, at a height not, perhaps, 

 often exceeding 4500ft; or 5000ft. Between Useigne and Vex in the 

 Val d'Herens, near the entrance to the Val d' Heremence, where 

 bushes of alder, sloe, birch, and oak slope down the valiey side to the 

 river, and the Eupatorium and thistle flowers are covered with Dryas 

 paphia, Argynnis adippe, A. niobe, Callimorpha hera, etc., and between 

 St. Niklaus and Zermatt, where similar slopes spread out into open and 

 more level cultivated areas, where ash -trees are frequent, and blackthorn 

 is found forming rude hedges, or scattered over the rocky slopes 

 above — in both these places a fine large race of R. betulae occurs 

 not . at all uncommonly. At the foot of the Saleve, near 

 Geneva, a fine, overgrown, tangled wilderness of flowers climbs 

 the stony slopes, amid bushes of blackthorn and birch, to the edge 

 of the wood that runs up the sides of the mountain, whilst below, 

 hedges, in which sloe is intermixed, run down to the orchards just 

 beyond. This is another well-known haunt for this insect. Far 

 down in the Basses-Alpes a sparkling stream forms the floor of a 

 mountain glen, at the side of which birch and willow grow abundantly, 

 whilst blackthorn and bramble climb the rock ledges above, and a 

 wealth of wild flowers edges the sides, the stream being finally 

 carried over the bed of the Eaux-Chaudes just above the Baths at 

 Digne. This glen is another spot in which one can find R. betulae much 

 at home in early August. A steep sloping path over the hot sunbaked 

 black rocks of the Verdon Valley, leading up from Alios to the 

 Lac d' Alios, leads out upon some cultivated fields that slope down to 

 the torrent on one side, and are edged by the steep rocky sides of the 

 slope, on which an abundance of barberry, dwarf blackthorn, and wild 

 gooseberries have made their home, on the other, and where a few trees of 

 wych elm are helped by blackthorn, bramble, and barberry to make thick, 

 dense hedges that serve as a support to the road and a means of safety 

 against falling rocks and stones. Here again R. betulae is at home, in 

 a spot not, after all, so much unlike the rock-strewn level in the 

 mountains between Bobbie and Au Pra, to which already reference 

 has been made. These, at any rate, will give some idea of the various 

 habitats in which we have found this species. Two hundred years 

 ago the species was not uncommon in the woods that are now super- 

 seded by houses forming suburban London. In 1720, Albin records 

 it as inhabiting the Hornsey Woods, where, in fact, it occurred more 

 than 100 years later, when it was yet one of the then restricted bits 

 of the old forest land that was still left on the outskirts of London, 

 for Stephens noted that, in 1828, it was yet to be found there. 

 Wherever these old forest remnants are still to be found, R. betulae still 

 exists, e.g., Darenth Wood, Epping Forest, etc. Stephens observes 

 that it inhabited Birch Wood about the middle of August, Coombe 

 and Darenth Woods being at the time its other best known haunts near 



