96 [April, 1894. 



This alone would, in my opinion, be sufficient to warrant their dis- 

 tinctness, even if the larvae did not also throw their weight into the 

 scale. Lapponica is yellow, with the cephalic ganglia brown and 

 distinct, yet at the same time less conspicuous than the head. No. 1 

 is greenish-white, with the head very pale brown, the cephalic ganglia 

 dark and distinct, and markedly more conspicuous than the head. No 

 trace o£ the ventral cord is discoverable po long as the larvae are in situ, 

 but it becomes visible in lapponica when removed from its mine, and 

 may also perhaps in No. 1, but my notes are silent on the point. 

 Lapponica is single brooded and feeds in June, though occasionally an 

 odd mine or two may be picked up late in the autumn ; No. I feeds a 

 little later, in July, and has no second brood. The cocoon of lapponica 

 is smooth, and varies from dark brown to almost black ; it is difficult 

 to find, as it is commonly placed under the soil. I have not yet seen 

 the cocoon of No. 1. 



Distinguenda and hetulicola. The mines are small and narrow — 

 especially in distinguenda — are generally much contorted, several being 

 often crowded together in a leaf, and begin coarsely, very differently 

 from the slender and delicate commencement adopted by the two 

 preceding species. Here the resemblance between them ends. Dis- 

 tinguenda fills its gallery with brown frass very neatly coiled, and is 

 always most constant and true to type. Betulicola deposits its black 

 frass without any order, and is distinctly irregular in its practice ; 

 usually it does not much more than half fill its gallery, but not un- 

 frequently it very nearly does so, the mine at the same time being 

 narrower and shorter than common, and coming extremely near the 

 mine of luteella. The irregularity, there can be little doubt, is de- 

 pendent on the nature of the leaves, for it will be found that the latter 

 are appreciably thinner, and their network of veinlets more open 

 where the gallery is only half filled than where it is more completely 

 so. Larva — in distinguenda the head is dark brown, a black square- 

 shaped spot (skin mark) is present on the under-side of segment two, 

 the ventral cord is black and very distinct, and the urinary tubes are 

 also plainly visible. Betulicola differs in the ventral cord and spot on 

 segment two being brown instead of black, and in wanting altogether 

 the urinary tubes. Both are double brooded. Betulicola has a singular 

 fancy for the little seedling plants, and may appear to be unaccountably 

 scarce if the search is confined to the taller bushes, whilst all the time 

 it is in abundance at the ground level. The cocoons are spun above 

 ground, distinguenda being buff in colour, hetulicola brown. 



