of the Flea Ceratophyllus vagabundus. 457 



The whole mass was next cut round with a sharpened 

 needle point and successfully transferred to a 10 per cent, 

 KOH-solution, only a small fragment (s) adhering to the 

 inner stone wall. In potash considerable swelling took 

 place, and the following points were noted. 



(a) The bulk of the mass consisted of a fully formed 

 flea, a (^ Ceralophi/llus. 



(b) The paper-like plug at the cut end of the stone waa 

 evidently part of a cocoon wall. 



{c) The incomplete remains of a cast-of! skin, the rest 

 (s) had adhered to the inner surface of (b) as noted above. 



(d) A fragment of the seed and seed-coat persisted. 



(e) The presence of nmnerous black hollow globules. 



(/) The whole was woven together by a mass of fungus 

 mycelium. 



We are now in a position, I think, to reconstruct with 

 some degree of probability the story of the vicissitudes of 

 this hawthorn stone and its contents. 



The haw was eaten in the autumn by one of our thrushes, 

 probably a blackbird {Turdus merula L.), and the stone duly 

 evacuated. Seized on by a mouse {Mus sp.) it was next 

 carried to the little rodent's winter storehouse high up on 

 the truss beneath the roof. 



Some time later the seed was devoured, but, as the hole 

 made in the stone by the preliminary biting of the mouse 

 was somewdiat smaller than us;iial, the seed contents were 

 not completely removed. 



Meanwhile, somewhere near the mouse store a passerine 

 bird, perhaps a starling {Sturnns vidgaris L.) or a jackdaw 

 (Corvus nionedula L.), had either nested or roosted long 

 enough to disseminate its fleas. One of these may have 

 laid its eggs in the rubbish and dust of the mouse store, 

 or it may have reached there as a larva seeking safe 

 quarters for pupation. In any case, a flea larva ultimately 

 squeezed its way into the empty stone, spun up and v^ent 

 through its transformations. On its emerging as an adult, 

 the cocoon was ruptured on the side towards the micropyle 

 and the flea ultimately died of starvation. It had 

 previously evacuated its gut of the accumulated waste 

 products of the pupal stage in the form of the characteristic 

 black globules already referred to. 



The last chapter of the story records the entrance of a 

 fungus which destroyed all the soft parts of the dead 

 insect, down even to the membranes between the sclerites. 



