occurrence of some of the supposed peculiar species on the continent. The list has now been revised by the Rev. Canon Fowler, author of the best modern work on the British Coleoptera, who has kindly furnished some valuable notes.
For the Lepidoptera I first noted all the species and varieties marked as British only in Staudinger's Catalogue of European Lepidoptera. This list was carefully corrected by Mr. Stainton, who weeded out all the species known by him to have been since discovered, and furnished me with valuable information on the distribution and habits of the species. This information often has a direct bearing on the probability of the insect being peculiar to Britain, and in some cases may be said to explain why it should be so. For example, the larvæ of some of our peculiar species of Tineina feed during the winter, which they are enabled to do owing to our mild and insular climate, but which the severer continental winters render impossible. A curious example of the effect this habit may have on distribution is afforded by one of our commonest British species, Elachista rufocinerea, the larva of which mines in the leaves of Holcus mollis and other grasses from December to March. This species, though common everywhere with us, extending to Scotland and Ireland, is quite unknown in similar latitudes on the continent, but appears again in Italy, the South of France, and Dalmatia, where the mild winters enable it to live in its accustomed manner.
Such cases as this afford an excellent illustration of those changes of distribution, dependent probably on recent changes of climate, which may have led to the restriction of certain species to our islands. For should any change of climate lead to the extinction of the species in South Europe, where it is far less abundant than with us, we should have a common and wide-spread species entirely restricted to our islands. Other species feed in the larva state on our common gorse, a plant found only in limited portions of Western and Southern Europe; and the presence of this plant in a mild and insular climate such as ours may well be supposed to have led to the preservation of some of the numerous species which are or have been dependent on it. Since the first edition was
published many new British species have been discovered, while some of the supposed peculiar species have been found on the continent. Information as to these has been kindly furnished by Mr. W. Warren, Mr. C. G. Barrett, Lord Walsingham, and other students of British Lepidoptera, and the first-named gentleman has also looked over the proofs.
Mr. McLachlan has kindly furnished me with some valuable information on certain species of Trichoptera or Caddis flies which seem to be peculiar to our islands; and this completes the list of orders which have been studied with sufficient care to afford materials for such a comparison. We will now give the list of peculiar British Insects, beginning with the Lepidoptera and adding such notes as have been supplied by the gentlemen already referred to.
List of the Species or Varieties of Lepidoptera which, so far as at present known, are confined to the British Islands. (The figures show the dates when the species was first described. Species added since the first edition are marked with an asterisk.)
Diurni.
1. Polyommatus dispar. "The large copper." This fine insect, once common in the fens, but now extinct owing to extensive drainage, is generally admitted to be peculiar to our island, at all events as a variety or local form. Its continental ally differs constantly in being smaller and in having smaller spots; but the difference, though constant, is so slight that it is now classed as a variety under the name of rutilus. Our insect may therefore be stated to be a well-marked local form of a continental species.
2. Lycæna astrarche, var. artaxerxes. This very distinct form is confined to Scotland and the north of England. The species of which it is considered a variety (more generally known to English entomologists as P. agestis) is found in the southern half of England, and almost everywhere on the continent.
Bombyces.
3. Lithosia complana, var. sericea. North of England (1861).
4. Hepialus humuli, var. hethlandica. Shetland Islands (1865). A remarkable form, in which the male is usually yellow and buff instead of pure white, as in the common form, but exceedingly variable in tint and markings.
5. Epichnopteryx reticella. Sheerness, Gravesend, and other localities along the Thames (1847); Hayling Island, Sussex.
6. E. pulla, var. radiella. Near London, rare (1830?); the species in Central and Southern Europe. (Doubtfully peculiar in Mr. Stainton's opinion.)
Noctuæ.
7. Acronycta euphorbiæ, var. myricæ. Scotland only (1852). A melanic form of a continental species.
8. Agrotis subrosea. Cambridgeshire and Huntingdonshire fens, perhaps extinct (1835). The var. subcærulea is found in Finland and Livonia.
9. Agrotis candelarum var. ashworthii. South and West (1855). Distinct and not uncommon.
10. Luperina luteago, var. barretti. Ireland (1864).
11. Aporophyla australis, var. pascuea. South of England (1830). A variety of a species otherwise confined to South Europe.
12. Hydræcia nictitans, var. paludris.
Geometræ.
13. Boarmia gemmaria, var. perfumaria. Near London and elsewhere. A large dark variety of a common species.
14. *B. repandata, var. sodorensium. Outer Hebrides.
15. *Emmelesia albulata, var. hebridium. Outer Hebrides.
16. *E. albulata, var. thules. Shetland Islands.
17. *Melanippe montanata, var. shetlandica. Shetland Islands.
18. *M. sociata, var. obscurata. Outer Hebrides. A dark form.
19. Cidaria albulata, var. griseata. East of England (1835). A variety of a species otherwise confined to Central and Southern Europe.
20. Eupithecia constrictata.. Widely spread, but local (1835). Larva on thyme.
21. *E. satyrata, var. curzoni. N. Scotland.
22. *E. nanata var. curzoni. Shetland Islands.
Pyralidina.
23. Aglossa pinguinalis, var. streatfieldi. Mendip Hills (1830). A remarkable variety of the common "tabby."
24. *Scoparia cembræ, var. scotica. Scotland (1872).
25. *Myelois ceratoniæ, var. pryerella. North London (1871).
26. *Howœosoma nimbella, var. saxicola. England, Scotland, Isle of Man (1871).
27. *Epischnia bankesiella. Isle of Portland (1888).
Tortricina.
28. Aphelia nigrovittana. Scotland (1852). A local form of the generally distributed A. lanceolana.
29. Grapholita parvulana. Isle of Wight (1858). Rare. A distinct species.
30. Conchylis erigerana. South-east of England (1866).
31. *Brachytænia woodiana. Herefordshire (1882).
32. *Eupœcilia angustana, var. thuleana. Shetland Islands.
33. *Tortrix donelana. Connemara, Ireland (1890).
Tineina.
34. Tinea cochylidella. Sanderstead, near Croydon (1854). Unique!
35. Acrolepia betulætella. Yorkshire and Durham (1840). Rare.
36. Argyresthia semifusca. North and West of England (1829). Rather scarce. A distinct species.
37. Gelechia divisella. A fen insect (1856). Rare.
38. G. celerella. West of England (1854). A doubtful species.
39. *G. tetragonella. Yorkshire. Norfolk. Salt marshes.
40. *G. sparsiciliella. Pembroke.
41. *G. plantaginella. A salt-marsh species.
42. G. Ocellatella (Barrett nec Stainton). Bred from Beta maritima. Very distinct.
43. Bryotropha politella. Moors of North of England. Norfolk (1854).
44. *B. portlandicella. Isle of Portland (1890).
45. Lita fraternella. Widely scattered (1834). Larva feeds on shoots of Stellaria uliginosa in spring.
46. L. blandulella. Kent.
47. Anacampsis sircomella. North and West England (1854). Perhaps a melanic variety of the more widely spread A. tæniolella.
48. A. immaculatella. West Wickham (1834). Unique! A distinct species.
49. *Œcophora woodiella?
50. Glyphipteryx cladiella. Eastern Counties (1859). Abundant.
51. G. schœnicolella. In several localities (1859).
52. Gracilaria stramineella. (1850). On birch. Perhaps a local form of G. elongella, found on alder.
53. Ornix loganella. Scotland (1848). Abundant, and a distinct species.
54. O. devoniella. In Devonshire (1854). Unique!
55. Coleophora saturatella. South of England (1850). Abundant on broom.
56. C. inflatæ. South and East of England. On Silene inflata. ? continental.
57. C. squamosella. Surrey (1856). Very rare, but an obscure species.
58. C. salinella. On Sea-coast (1859). Abundant.
59. *C. potentillæ. South of England.
60. *C. adjunctella. Essex salt marshes. ? Lancashire (1882).
61. *C. limoniella. Isle of Wight. Feeds on Statice limonium.
62. Elachista flavicomella. Dublin (1856). Excessively rare, two specimens only known.
63. *E. scirpi. Wales and Sussex. Salt marshes.
64. E. consortella. Scotland (1854). A doubtful species.
65. E. megerlella. Widely distributed (1854). Common. Larva feeds in grass during winter and early spring.
66. E. obliquella. Near London (1854). Unique!
67. E. triseriatella. South of England (1854). Very local; an obscure species.
68. *Tinagma betulæ. East Dorset (1891).
69. Lithocolletis nigrescentella. Northumberland (1850). Rare; a dark form of L. Bremiella, which is widely distributed.
70. *L. anderidæ. Sussex. Dorset (1886).
71. L. irradiella. North Britain (1854). A northern form of the more southern and wide-spread L. lautella.
72. L. triguttella. Sanderstead, near Croydon (1848). Unique! very peculiar.
73. L. ulicicolella. In a few wide-spread localities (1854). A peculiar form.
74. L. caledoniella. North Britain (1854). A local variety of the more widespread L. corylifoliella.
75. L. dunningiella. North of England (1852). A somewhat doubtful species.
76. Bucculatrix demaryella. Widely distributed (1848). Rather common.
77. Trifurcula squamatella. South of England (1854). A doubtful species.
78. Nepticula ignobiliella. Widely scattered (1854). On hawthorn, not common. ? on continent.
79. N. poterii. South of England (1858). Bred from Larvæ in Poterium sanguisorba.
80. N. quinquella. South of England (1848). On oak leaves, very local. ? continental.
81. N. apicella. Local (1854). Probably confused with allied species on the continent.
82. N. headleyella. Local (1854). A rare species.
83. *N. hodgkinsoni. Lancashire.
84. *N. woolhopiella. Herefordshire.
85. *N. serella. Westmoreland and S. England.
86. *N. auromarginella. Dorset (1890).
87. *Micropteryx sangii. (1891).
88. *M. salopiella.
Pterophorina.
89. Agdistis bennetti. East coast. I. of Wight (1840). Common on Statice limonium.
We have here a list of eighty-nine species, which, according to the best authorities, are, in the present state of our knowledge, peculiar to Britain. It is a curious fact that no less than fifty of these have been described more than twenty-five years; and as during all that time they have not been recognised on the continent, notwithstanding that good coloured figures exist of almost all of them, it seems highly probable that many of them are really confined to our island. At the same time we must not apply this argument too rigidly, for the very day before my visit to Mr. Stainton he had received a letter from Professor Zeller announcing the discovery on the continent of a species of our last family, Pterophorina, which for more than forty years had been considered to be exclusively British. This insect, Platyptilia similidactyla (Pterophorus isodactylus, Stainton's Manual), had been taken rarely in the extreme north and south of our islands—Teignmouth and Orkney, a fact which seemed somewhat indicative of its being a straggler. Again, seven of the species are unique, that is, have only been captured once; and it may be supposed that, as they are so rare as to have been found only once in England, they may be all
equally rare and not yet found on the continent. But this is hardly in accordance with the laws of distribution. Widely scattered species are generally abundant in some localities; while, when a species is on the point of extinction, it must for a time be very rare in the single locality where it last maintains itself. It is then more probable that some of these unique species represent such as are almost extinct, than that they have a wide range and are equally rare everywhere; and the peculiarity of our insular climate, combined with our varied soil and vegetation, offer conditions which may favour the survival of some species with us after they have become extinct on the continent.
Of the sixty-nine species recorded in my first edition fourteen have been since discovered on the continent, while no less than twenty-two species and eleven varieties have been added to the list. As we can hardly suppose continental entomologists to be less thorough collectors than ourselves, it ought to be more and more difficult to find any insects which are unknown on the continent if all ours really exist there; and the fact that the list of apparently peculiar British species is an increasing one renders it probable that many of them are not only apparently but really so. Both general considerations dependent on the known laws of distribution, and the peculiar habits, conspicuous appearance, and restricted range, of many of our species, alike indicate that some considerable proportion of them will remain permanently as peculiar British species.