ORDER HYMENOPTERA 217 



of the members of this subfamily feed from the under sur- 

 face of the leaves eating away the lower parenchyma. 

 There are, however, in the type genus Phyllotoma and in 

 Phlebatrophia, several examples of miners. The European 

 Phlebatrophia nemorata has recently been reported as mining 

 leaves of birch in Nova Scotia. It has probably been re- 

 cently imported. One of us (Mrs. Tothill) has observed 

 this leaf-miner in Nova Scotia and has found that it has 

 the habit of spinning a silken lens-shaped cocoon within 

 the mine. 



Stranger still is the habit of Phyllotoma aceris mentioned 

 above. The following account of this insect together with 

 figures we take mostly from an excellent article by Pro- 

 fessor Ritzema Bos (1900). The adults of the phyllotomid 

 miner of maple, Phyllotoma aceris, emerge about the first of 

 May in Europe at which time the trees are usually well in 

 leaf. They soon pair and the females begin to lay eggs in 

 the leaves of maples, especially Acer campestre and Acer 

 pseudo-platanus. The eggs are usually placed near a lateral 

 vein. They soon hatch and the larvae grow rapidly, be- 

 coming full-fed before the end of June. In feeding the 

 upper and lower cuticles and, at least in large part, the veins 

 are left undisturbed. The mines, though often extending 

 beyond two or three of the main lateral veins, never cross 

 the midrib. At first the mines show as white spots but 

 later become more darkened as dampness scatters the color 

 of the excrement. There may be from one to five mines 

 in a leaf but with only one larva in a mine. The number 

 of moults has not been certainly determined but the skins 

 are shed in one piece. The frass is loose and dry in the mine 

 and therefore shakes about. 



The full-grown larvae are 6 to 7 mm. in length, somewhat 

 broad and short and more or less oval in cross-section. 

 There are three broad thoracic segments and ten succes- 

 sively narrower abdominal ones. In color they are white 



