440 f.F.r/DOPTERA. 



Exceeding]}- variable, and in local forms, or race?, which, 

 however, shade imperceptibly into one another. The speci- 

 mens usually found on chalk hills inland have the purple- 

 brown colour but little clouded with white, the white bar 

 before the first line, the white cloudinj,' along the middle of 

 the costa, and the hinder white cloud, being in them often 

 absent, leaving the surface purple-brown, with only very 

 slight indications of paler transverse lines ; while those from 

 the rocks of the sea coast, especially away from the chalk, 

 show the whiter cloudings in varying degrees and often 

 very brightly, and are altogether handsomer and more 

 striking looking insects. This last form was introduced, 

 in 1866, to our lists as a distinct species, under Dupouchel's 

 name of suhornatella, while, both having previously been 

 included in dilutdlii, Steph., the name of adornatrlln, Tr., 

 was resuscitated for the other supposed species. Now that 

 it is known that both shade imperceptibly into one another, 

 and that the food-plant and habits are identical, the present 

 name has been resumed. 



On the wing from June till the beginning of September, 

 apparently in a single generation, of slow emergence. 



Larva five-eighths of an inch long ; head and second seg- 

 ment black, slightly glistening; body dull greenish-grey, 

 more yellowish upon the back ; dorsal and subdorsal lines 

 narrow, dark greenish-grey ; third, fourth, and fifth seg- 

 ments much wrinkled upon the back ; raised dots shining 

 black ; legs black. 



May to June or July, but possibly from the preceding 

 autumn, on wild thyme (^Thymus sei'pyllum), living in a long 

 loose tube of thin silk, almost like spider's web, on the 

 ground, among the jirostrate branches of the plant ; feeding 

 on the leaves. Very partial to plants growing on a rock or 

 on hard stony soil, and I found it constantly associated 

 with yellow ants (Formica flava), its tube completely mixed 

 with their nests, (fehris, and excavations. Apparently it was 

 absolutely secure from any injury by them. 



o 



