SUBORDER FRENATAE 83 



still within seems like a considerable feat — somewhat like sawing 

 off a limb of a tree while seated on it, and yet not getting a tumble. 

 The cases of the adults vary somewhat in size, but an average 

 specimen has the larger piece on top about 0.4 inch long and 0.3 

 inch wide. 



Thus it would appear that the larva lives as a miner 

 within the leaf during its first stage only, beginning its 

 operations during the month of May. Then it is a surface- 

 feeding case-bearer during perhaps four larval stages, ex- 

 tending through the months of July and August and into 

 September. Then it pupates within the case and hiber- 

 nates in the same among the fallen leaves on the ground 

 beneath the trees. Then it emerges in late Spring as a 

 moth having a wing expanse of half an inch, and a color of 

 brilliant steel blue w T ith violet reflections, and a tuft of 

 orange-yellow hairs upon the head. 



Of this family Europe has more representatives than we, 

 and especially more species that are miners in early life, but 

 with only a few exceptions (as Incurvaria capitella which 

 continues to burrow in Ribes stems) they become case 

 bearers in late larval life. Adela and Nematois burrow in 

 flowerheads or seed capsules at first, but Phylloporia, 

 Nemophora and at least some species of incurvaria begin 

 life as miners. 



Phylloporia bistrigella of Europe mines in Birch leaves. 

 The mine usually begins near the tip of the leaf as a narrow 

 gallery. Proceeding more or less directly along the midrib 

 it grows slightly wider and near the base it turns up along 

 the leaf margin where it expands somewhat abruptly into a 

 blotch. When the larva is full-fed it cuts oval pieces from 

 the floor and ceiling of the newest made part of the mine and 

 sew T s them together as a case. 



In this it descends to the ground for pupation. Mining 

 is done in July and August and the adult emerges the 

 following June. Nemophora begins as a leaf-miner but 



