1890.] 133 



and under-side of abdomen at the sides more finely punctured, the middle third of 

 the venter smooth. Sternum blackish, faintly shining. Head, thorax and scutellum 

 brownish-green, with a faint brassy shine. Corium more brownish-black, opaque ; 

 membrane black. Under-side of abdomen reddish-brown, smooth, the punctured 

 sides blachish-brown. Antennse dull brown, the base yellow. On each side of the 

 thorax between the two spines, but more towards the middle of the disc, is an 

 elevated, smooth, round, yellow spot ; the anterior acute spines are reddish-yellow. 

 In the basal angles of the scutellum is a hard, smooth and elevated yellow spot, ex- 

 tending obliquely backwards ; from opposite the end of these two spots runs, in the 

 middle of the scutellum, a very narrow, yellow, longitudinal line, which is dilated 

 towards the apex of the scutellum, the whole of which it occupies. The lateral 

 margin of the corium is narrowly bordered with yellow, and in the middle of the 

 disc is a yellow longitudinal line, dilated towards its posterior end. Coxse, trochan- 

 ters, and the basal quarter of the femora bright yellow, the rest of the femora 

 blackish-brown, tibiae tawny, with the base and tip brownish, tarsi tawny." 



Mayr, Signoret aud Distant describe the antennae as being four- 

 jointed, Assmann as five-jointed. But it is evident that the first short 

 and thick joint mentioned by Assmann is only the basal node o£ the 

 antennae. 



Forssa, Finland : March, 1890. 



NOTES ON GRACILARIA POPULETORUM, ELONQELLA, AND 

 FALCONIPENNELLA. 



BY JOHN H. WOOD, M. B. 



These three Oracilarice form part of a very natural group that is placed in the 

 " Manual " at the head of the genus, and is characterized in the perfect insects by the 

 presence of a costal triangle, and in the larvfe by being solitary in their habits, and 

 living upon trees or shrubs, the leaves of which they mine in the first half of their 

 existence, and fold or roll into chambers in the last half. In most of the members of 

 the group the mine is compound, consisting partly of a very shallow and superficial 

 gallery, which, from the inconspicuousness of the " frass," looks not unlike Dipterous 

 work, and partly of a small LithocoUetis-like blotch. A point to be noticed about 

 the chambers is, that the number which each species constructs is singularly invari- 

 able. In all but one of them there are two of these structures, so that, counting 

 the mine, the larvse may be said to have three distinct householdings, each house- 

 holding, as I hope to show, being associated with a particular stage in the life of the 

 insect. The form of the first chamber often varies much in the same species, and 

 appears to depend chiefly upon the size and shape of the leaf, or upon the part at 

 which the larva sets to work ; but the form of the second or final chamber is on the 

 contrary most constant, and affords a useful character for differentiating the species. 

 The difiiculties in the way of ascertaining some parts of their economy, and especially 

 the relationship just alluded to between tlie larva and its domicile, were by no means 

 slight, and in the case of the early or mining life could only be indirectly overcome, 

 since opening a mine meant the death of the larva ; but in the chamber-life the 



