LINNEAN SOCIETY OT LOTSTBON. XXl 



the aquatic conditions of the insect. These are of different ages, 

 and may be termed " larva " and " nymph " respectively, the larger 

 individual having strongly developed rudimentary wings, and 

 being evidently nearly mature, while the smaller one possesses 

 only the thoracic lobes which indicate the position of the wings. 

 Tliese two states are described in detail. 



This remarkable insect would appear to be common at Christ- 

 church, the cast subimaginal skins being no rarities sticking on 

 walls, windows, &c. The Eev. A. E. Eaton considers the genus 

 allied to Siphlurus, and points out that the structure of the aquatic 

 conditions shows the creature to be of active habits, swimming 

 freely among water-plants in search of its prey, and not semi- 

 fbssorial as is the case with some members of the family. The 

 great lateral expansion of the margins of the abdominal segments 

 is without a parallel in any known perfect insect of the group. 

 The author concludes by tracing the relations of Latreille's genus 

 of Branchiopod Crustacea, Prosopistovia, according to the ob- 

 servations of N. and E. Joly, two French entomologists (father 

 and son), who have rediscovered the creature, and who point out 

 that there is scarcely any doubt as to the genus having been 

 founded on the aquatic conditions of some species of Ephemeridae. 



Some discussion as to the relationships of Oniscigaster took 

 place, in which the Rev. A. E. Eaton (present as a visitor) and 

 Sir John Lubbock took part. 



April 2ud, 1874-. 

 J. GvrtN Jbffeeys, Esq., F.R.S., in the Chair. 



J. H. Mangles, Esq., was elected a Eellow. 



The following paper was read : — 



1. " On the Morphology of the Skulls in the Woodpeckers 

 (Picidse) and the Wrynecks (Tungidse)." By W. Kitchen Parker, 

 E.R.S. Communicated by the President. 



