THE MARSH FRITILLARY. 105 



web, which is attached to a leaf or drawn-together leaves. The 

 early stages are figured on Plate 70. 



Kane {Catalogue of the Lepidoptera of Ireland), referring to 

 this species, remarks : " This butterfly has been known to 

 increase so prodigiously that whole fields and roads became 

 blackened by the moving myriads of larvae. An instance of 

 this was observed by the Rev. S. L. Brakey, near Ennis, Co. 

 Clare, where he drove out to see a reported * shower of worms,' 

 and found as above described, the larvae being so multitudinous 

 in some fields that the black layer of insects seemed to roll in 

 corrugations as the migrating hosts swarmed over each other 

 in search of food. The imagines that resulted from the starved 

 survivors were extremely small and faded in colour." 



These caterpillars are destroyed in great numbers by 

 Hymenopterous parasites, chiefly Apanteles, and it is almost 

 certain that a large percentage of those collected will prove to 

 have been stung. 



The butterfly is on the wing in May and June, and seems to 

 affect damp meadows, marshy ground on the sides of hills, and 

 such kind of places. It does not necessarily occur wherever 

 its food-plant is abundant, but scabious is always found to be 

 present in the haunts of the butterfly ; so if we know that the 

 insect occurs in a particular district we should probably get a 

 clue to its exact whereabouts by noting the likely places in that 

 district where the food-plant flourishes. 



Although it has seemingly disappeared from various English 

 localities where it was formerly common, the butterfly may be 

 found in many parts of the British Islands, but it is local and 

 does not occur northwards much beyond the Caledonian Canal. 



Abroad it spreads over Europe to Northern Africa, and its 

 range extends eastward through Asia to Amurland and Corea. 



The fine butterfly next in order is regarded as a member of 

 the Danainae by most authors. Although its generic position 



