HARD WICKE 1 S S CIENCE- G SSIP. 



"5 



Asia is related to that of North America — a subject 

 on which I may have more to say later on. With 

 regard to the origin of Tudora in Europe (p. 26) it 

 is possible that the ancestor of T. femtginca was 

 carried across the Atlantic on floating timber by the 

 Gulf Stream, as the operculum would help it greatly 

 in resisting the influence of sea-water. And it is 

 noteworthy that the T. ?negacheila, of Curacoa, has a 

 habit of climbing trees. — T. D. A. Cockerell, West 

 Cliff, Custer Co., Colorado. 



Grapta C-ALBUM. — On page 44, your corre- 

 spondent A. G. T. has a note on Vanessa {Grapta) 

 C-album, asking whether it is known to be double- 

 brooded. In reply, I may say that Mrs. Hutchinson 

 has proved without doubt that it is so, and has 

 recorded her observations in the "Entomologist's 

 Monthly Magazine," 1887, p. 186. Mr. W. H. 

 Edwards has some very interesting remarks on this 

 species in "Canadian Entomologist," 1887, p. 2, in 

 which he shows that C-album is represented in 

 America by three species : G. comma, G. satyrus and 

 G. faunas. Now the first two differ from G. C-album 

 in their preparatory stages, but faunus is still held 

 by many authors to be a race of C-album. Mr. 

 Edwards continues, " Faunus is a sub-boreal species, 

 flying from one ocean to the other . . . and being 

 boreal and one-brooded, it is fair to presume it came 

 from the north ; that at the time, ages ago, when the 

 two continents were united, the species occupied the 

 northern parts of both. When the separation took 

 place, the European branch split into numerous 

 varieties, and became double-brooded, yet retained 

 its identity as one species . . . one multiform species." 

 So he concludes that /annus, la single-brooded, 

 unvarying boreal species, is near to the primeval type 

 from which sprung the one variable European species 

 and the twelve known North American species. [P.S. 

 — I may mention that the cause of the destruction of 

 insects frequenting lime-trees (p. 43) is the tomtit 

 {Parus) and no poison.] — T, D. A. Cockerell, West 

 Cliff, Custer Co., Colorado. 



Entomological Society of London. — At the 

 last meeting of this society, Mr. Goss read a letter 

 from Mr. Bignell, correcting a statement made by 

 Mr. Poulton at the March meeting of the society, to 

 the effect that the variety valezina of the female of 

 Argytmis paphia did not occur in Devonshire. Mr. 

 Bignell said that the var. valezina was included in 

 Mr. Reading's ' ' Catalogue of Devonshire Lepi- 

 doptera " ; and further, that he had himself taken 

 specimens of this variety in Bickleigh Vale, Devon. 

 Mr. Waterhouse read a paper entitled "Additional 

 Observations on the Tea-bugs (Helopeltis) of Java," 

 and exhibited a number of specimens of these insects. 

 He said that the species infesting the cinchona in 

 Java was supposed to have been introduced from 

 Ceylon in tea, but that he had discovered that the 



species on the tea and on cinchona in Java were 

 distinct, and that both species were distinct from 

 Helopeltis antonii of Ceylon. 



Geographical Distribution.— Mr. T. D. A. 

 Cockerell will allow me, I know, to make the sug- 

 gestion — considering so little is known at present of 

 the why and wherefore of the distribution in space of 

 the land and freshwater mollusca — that the distribu- 

 tion in time be the only test ; and that if any one 

 given species, or any form of which we may reason- 

 ably expect it to be a derivative, be found in the 

 pliocene or anti- pliocene fauna of a district or sec- 

 tion, then we may believe it to be an autochthon of 

 that district or section. For example, should Plan- 

 orbis parvus, or some one species closely allied to it, 

 be found fossil in the pliocene or anti-pliocene for- 

 mations of the countries reckoned in his boreal 

 section, then we may more positively aver that its 

 "metropolis" of distribution was a northern one. 

 His proposed test {ante, page 25) seems to me scarcely 

 to hold water as a special way of working by the 

 very exceptions he makes to the rule he has formu- 

 lated, because colonists have certainly taken over 

 many species of which there could, by their very 

 ignorance of natural history, be no record ; and if a 

 prolific species were taken over it could delude a 

 naturalist visiting the country after a lapse of years 

 into reckoning it as indigenous, by reason of its 

 attained distribution, when it was only an immigrant 

 after all.— y. W. Williams. 



CONCHOLOGY. — I have just got two advance copies 

 of a new work on the British Unionidae. It consists 

 of illustrations of a hundred different forms of Unios 

 and Anodons. There are no descriptions, but there 

 is an introduction in which the types of various 

 authors (1804-1879) are reproduced, to show the 

 confusion that has existed in regard to type forms. 

 The first edition, which is preliminary and subject to 

 alteration, is limited to about twenty copies. The 

 second and revised edition, which may number one 

 hundred copies, is designed to contain short descrip- 

 tions, together with exact localities for each form 

 illustrated. It may be remarked that the author is a 

 follower of the splitters, and some of the new-named 

 forms are in my opinion too near others to be sepa- 

 rated. — Geo. Roberts. 



The British Slugs.— The author of the inter- 

 esting papers entitled " Slug Gossip," which appeared 

 in Science-Gossip for last year, proposes (p. 244) 

 the use of Lehmaiuiia as a genus. It is, however, 

 at best only a sub-genus, and is only used as such 

 by its author, Heynemann ("Die nackten Land- 

 pulmonaten des Erdbodens," p. 85), who includes in 

 it Umax arborum, L.flavus {variegatus), L. azrulans 

 and L. montenegrinus. It would appear, however, 

 that Agriolirnax, Morch, containing the British species 

 agrestis and Icevis, must be accepted as a true genus, 



