NOTES ON COLEOPHORA TEOGLODYTELLA. 65 



Riiviex, Plantayo, etc., whereas in the latter, the larvaB feed more 

 generally on Salix, Fraxinus, Crataegus, etc. Thus the imagines, pro- 

 duced by the former larvae, on emerging, will dry their wdngs and rest 

 after that on the dock stems, where a variegated green shade, assimi- 

 lating with the shadows under the leaves, forms an efficient protection. 

 Those produced by the latter larvae, emerge at the base ofthe tree they have 

 fed on, and climb up the trunk to dry their wings, where, in turn, their 

 light colour, agreeing wdth the light blotches on the trunks, again protects 

 the insect. I do not seek to explain the dark green coloration of P. ab. 

 olivacea as being due to natural selection of those fitted for a resting 

 habit on smoke-blackened stone Avails, for the walls here, with one 

 exception, are usually light m colour. I stated above that the numbers 

 of ab. olivacea decreased as we passed southward from Birtley. This I 

 explain readily by my theory ; for, though still in a district in which 

 coal pits and smoke abound, the surroundings are the well wooded 

 estates of the Earl of Durham and others. 



I mentioned an exception to the rule that the w^alls here, are in 

 general, light in colour. The main road between London and Edin- 

 burgh passes through this village. It formerly, about half a mile to 

 the north, went due north, but many (more than 60) years ago, to 

 shorten the distance between Durham and Newcastle, it was diverted 

 to the north-west. The old road yet remains, and it is bounded by an 

 old blackened wall for about a mile. Hoav old this wall is one may 

 glean from the fact that near it, the Tway blade (Lister a cordata) and 

 Water Avens {(jreion rivale) linger as the last survivors of their race in 

 the district. What makes it specially interesting, is that along that 

 wall a local race of P. ehi has been evolved, which ranges in colour 

 from slate through blue-black to black. These specimens I take to 

 show true melanism, due to their surroundings. That it bears little 

 relationship to the green of P. ab. olivacea is readily proved by bleach- 

 ing both by exposure to sun. P. ab. olivacea bleaches to a pale prim- 

 rose tint, w^hereas these blues and blacks simply show a tint of their 

 original colour after exposure. 



These notes are not intended to be final, but are put forth with the 

 intenfc of pointing out a detail, which, I think, has been overlooked in 

 investigating the local variation of species in mining and manufac- 

 turing districts. 



Notes on Coleophora troglodytella. 



By HENEY J. TUENEE, F.E.S. 



CoLEOPHOKA TEOGLODYTELLA. — At the Same time that Mr. Bankes sent 

 me Coleophora conyzae larvae, he also sent a very nice batch of thelarvse 

 and cases of C. troglodytella, with the remark that " the species was 

 found chiefly on Inula conyza, but was also common on /. dysenterica, 

 to which it is even more partial than to I. conyza, w^hen it has the 

 choice." These larvae were found in the Isle of Purbeck on April 25th, 

 1904. They fed well for a time on the plants of I. conyza, which I had 

 potted, and, unlike C. conyzae, they were by no means restless. The 

 portion of the slender cylindrical case, which had come over the winter, 

 was dirty and weather-worn, and very distinct from the new whitish 

 insertion of spring manufacture. The additions soon became browned, 

 and thus the cases varied in dinginess in stripes according to the age 



