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Mobility op Spines on Certain Insects' Eggs. 



By H. Davis, F.R.M.S. 



(Communicated by Mr. Curties. August 26th, 1870.) 



The following communication from Mr. Davis, addr ssed to Mr. 

 Curties, was read by that gentleman : — 



Encouraged by your opinion that my observation of the mobility 

 of spines on certain insects' eggs, would be a suitable offering to 

 the Quekett Club, I venture to send some brief notes thereon, a 

 few objects and illustrative drawings for exhibition at the meeting, 

 and a parcel of photographs for distribution among the members. 

 The discovery, such as it is, is a simple matter, and lies in a nut 

 shell, or rather in an egg shell. You know that the eggs of some 

 bird parasites have lately attracted much attention from their 

 novelty and peculiar beauty ; foremost among them, the eggs found 

 on the black* quilled Peacock, and on the Mallee bird: now the 

 elegantly curved petaloid spines on the former quickly uncurl, 

 straighten, and contract on the lid ivhen the egg is placed under 

 water. They remain thus closed until the water is removed, when, 

 as the egg becomes dry by evaporation, the spines loosen ; they 

 gradually and gracefully recurve until the egg again assumes its 

 flower-like form. A group of these eggs in drying make a pretty 

 sight in the microscope, — it is a bouquet of flower-buds actually 

 blooming under the eye of the observer. 



The action of the spines seems independent of vitality, and is 

 renewed apparently as often as moisture is applied or removed ; 

 thus, on one of my slides, some of the lids are gone and the shells 

 empty, while the contents of other unhatched eggs are 

 shrivelled and dead ; still all the spines continue to contract and 

 expand on provocation after a score of immersions. 



The parasite eggs found on the Mallee bird possess appendages 

 actuated precisely as^are those of the species described ; these are 



Journ. Q. M. C. No. 13. l 



