SCIENCE-GOSSIP. 



13 



addition to the evidence given by Mr. Kew in favour 

 of its being indigenous, there is the fact that it 

 has been found in the pleistocene of Cambridge. 

 There is one species which Mr. Kew has omitted, 

 perhaps because it occurs in sHghtly brackish 

 water as well as fresh, namely, Paludcstyina 

 (Hydrobia) jenkinsi, Smith. The facts concerning 

 this species are so recent that there is no need 

 here to recapitulate them. First described from the 

 Thames Marshes, where it swarms in countless 

 myriads, it has since been recorded from Topsham, 

 Sandwich, near Lewes, and Staffordshire. Mr. 

 Lionel E. Adams, in 1892, suggested that it might 

 have been introduced from the Baltic. That it is 

 an introduction there can be but little doubt, but 

 until it has been found in some other locality 

 outside the British Isles it is waste of time to 

 speculate about its true habitat. In conclusion, I 

 must differ most heartily from Mr. Kew's statement 

 that " we are unable to distinguish our native fauna 

 with any degree of certainty " ; a careful examination 

 of the more recent deposits is all that is required, 

 and when this is done it will be found that not only 

 will our true molluscan fauna be known, but that 

 many problems connected with distribution will be 

 settled also. 



Bencnden, Mackenzie Road, Beckenham, Kent. 



AQUATIC HYMENOPTEROUS 

 INSECTS. 



By Fred. Knock, F.L.S., F.E.S. 



T T NDER the above title several minute parasitic 

 hymenoptera have been described, notably 

 the two found simultaneously by Sir John Lubbock 

 (Linn. Trans., vol. xxiv, p. 135). The habits 

 and economy of hymenoptera are so varied that 

 the wonder is that so few have been found inhabit- 

 ing either the eggs or larvae of aquatic insects. I 

 venture to think that one reason for this is that the 

 study of the British hymenoptera, especially the 

 Chalcididas, has been much neglected by ento- 

 mologists. The present condition of this family in 

 our national museum proves that very little 

 attention has been given either to re-arrange or 

 add to our indigenous species. This is much to 

 be regretted, as frequently an enquirer as to the 

 name of a minute insect has the greatest difficulty 

 in making it out. Another reason why our 

 progress is so slow in discovering new species in 

 this branch, is that those who study and work so 

 hard at the rotifera appear not to have time to 

 consider other creatures which may be drawn into 

 their nets. As an instance of this, it was only 

 by the merest chance that the first specimen of 

 "an aquatic hymenoptera insect" caught last 

 year was not emptied out without any record, for 

 the " pondist," when he first saw it, " thought it a 



fly which had tumbled into the water " ; but by a 

 chain of circumstances it was rescued and recorded 

 (SciENCE-Gossip, vol. ii, N.S., p. 89), and there is 

 now every probability of its life-history being fully 

 worked out. I have already proof that this most 

 extraordinaryaquatichymenopterondoesxof confine 

 itself to laying its eggs in those of dragon-flies. 



Last year I was fortunate in obtaining a large 

 number of this insect (males and females), keeping 

 many of them alive in water for a considerable 

 time, enabling me to observe the habits and 

 economy of the fly, which, after most careful 

 microscopic examinations of the thoracic structure, 

 antennas, etc., I found to agree in every point with 

 Haliday's description of Caraphractus cinctus. The 

 unique character of this genus being the " reeled " 

 metathorax, to show which I have prepared a 

 number of specimens in various positions. 



Owing to the kindness of Dr. R. F. Scharff, 

 Director of the Dublin Science and Art Museum, I 

 have been enabled to make a lengthy and exhausti\e 

 examination of the original Haliday type collection 

 of British Mymaridse, from which I have gained 

 invaluable information, and though many of the 

 carded specimens are " hoary with age " and gum, 

 I hope, with the help of the hundreds of specimens 

 which I have mounted for the microscope during 

 the past twenty years, to unravel some of the 

 mystery and doubt which appear to have sur- 

 rounded this family, containing, as it does, the most 

 minute and most exquisitely lovely of winged insects. 



The strange Prestwichia aquatica, Lubbock, has 

 not been observed since its first capture in 1862. 

 May I ask all " pondists," or '• muddists," as they 

 delight to call themselves, to keep an extra vigilant 

 eye open for this little-known aquatic hymenopteron, 

 which, however, does not belong to the Mymaridae. 

 I have succeeded in breeding several species of 

 semi-aquatic hymenoptera from various sources, 

 but have not yet identified them. 



21, Manor Gardens, Hollo-cay, London, N. 



Hibernation of Pararge Egeria. — I have 

 had under observation, during this winter, a brood 

 of the " speckled wood '" butterfly {Pararge egerui), 

 which I raised from ova deposited at the end of 

 August, 1S95. Some of the various members of 

 this brood have behaved unusually during hiber- 

 nation. The larger portion fed up rapidly in 

 autumn, turning to pupa;, the remainder being still 

 in the larval condition. It is usual, I believe, for 

 this species to hibernate as caterpillars. I placed 

 half the pupa: of this brood out of doors, and the 

 rest were kept in our dining-room, where there is a 

 fire daily during winter. No change was observed 

 until the first week in February, when some of the 

 chrysalides began to turn dark-coloured, and the 

 first perfect example emerged on February yih. 

 About the same time, the larvx, which had 

 remained passive, commenced to feed, and are 

 rapidly progressing towards maturity.— y. H. 

 Carpenter, Johnson Villa, GleneagU Road, Striatham, 

 SAV.; February i^th, 1S96. 



