41 



REMARKS ON OUR DIPTEROUS PLANT-MINERS, AND 

 THE PLANTS THEY AFFECT. 



By Peter Inchbald, F.L.S. 



Before I mention the families of plants, and the mining- 

 larvse that affect them, it may perhaps be well to say a few words 

 on the habits of life, so far as I have noticed them in my own 

 neighbourhood, of this somewhat neglected group of Diptera. 

 The tunnel, which tells us often of a whole summer's life, may be 

 readily seen on the surface of the leaf. As the larva grows and 

 feeds the tunnel becomes larger and wider; thus the miner 

 adapting itself to its requirements. Sometimes the pulp is 

 consumed by the feeder, and an unsightly blotch is all that is left 

 to evidence its depredations. Sometimes beautiful scroll-work 

 tells of the artistic labours of the little miner. This is especiall}'- 

 the case in the primrose-miner, whose tracings may be readily 

 seen on the primrose plants that cover the sloping banks of our 

 green lanes. The pulj), or parenchyma, is detached by a singular 

 instrument, which is readily seen by holding the minedleaf to the 

 light ; a black pickaxe-like process is protruded from the mouth. 

 This sways to and fro, often with wonderful rapidity, as it gathers 

 its supply of food. When it is about to assume the pupa-state 

 the larva mostly leaves its tunnel, and seeks either to bury itself 

 in the soil or to attach itself to the decaying leaves that have 

 served it as food and homestead. In some instances I have found 

 the pupa-case attached to the under side of the leaf; this is 

 especially the case in the miners of the primrose and hogweed. 

 These little mining-flies are not so difficult to hatch, if the 

 collector will only imitate Nature in her ways and means. The 

 affected leaves should be put into a large-sized glass-topped box, 

 wherein the larva may continue to feed a little longer. When 

 full-fed it creeps forth, and pupates either among the leaves or at 

 the bottom of the box. I have found a slight sprinkling of water 

 occasionally needed to supply Nature's provision of rain and dew, 

 and this should be continued during all the period of pupational 

 inertness. From my last season's larvae I am looking for quite a 

 bevy of imagines in April and May. 



Ranunculace^. — In this family I found during the present 

 year two miners, — one in the leaves of Ranunculus repens, the 



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