NOTES ON THE DISTRIBUTION OF THE BRITISH COLEOPTERA. 175 



$ 5. menillaefonnia, and the <?' s of »S. chr;/sidifori)ii>i even followed a ? 

 after it was pinned in a box, as well as being attracted by the net in 

 which one had been, (4) The <? s of S. ichneunioniformu copulated 

 regularly with $ .S'. iiuuiillacformi^ (the fact was observed more than 

 twenty times), whilst S' ^- chryaldiforwh was noticed to pair with the 



$ S. vii'iiillatfoniiia only twice. (5) <S'. ichneuiiionifonnis <? and S. 

 cltri/sidifoniiiii ? were observed to attempt to pair on one 

 occasion. These facts, coupled with the close resemblance in wing- 

 colour and -shape to N, ichneinnoniforinis, and to iS'. c/irt/siJifoDiiis 

 in its abdomen, have led Delahaye to suggest that S. iiu'nillae- 

 formis is a natural hybrid bet^\•een the two species. Certain points 

 arise out of this for consideration : (1) Why did not Delahaye observe 

 the pairing between <? 8. iclineumomforniu and 2 S. chrysidifortnis, or 

 the reverse, more than the single attempt {S. cJuysidiforiiiis ? and N. 

 ichitet(iii<»iifoniiis 3), that he records {loc. cit.) ? It appears that at 

 least these crossings should have been noted as frequently as those of 

 (J S. chrysidifoniiis or 3 S. icJtneiiiiionifo)-)))is with $ S. iiwyillaefoDiiis. 

 (2) Why did not the <? s of 8. chrysidifoniiis- pair with ? 6'. inciiiLlaeformix 

 as frequently as did ihe$ soiS.icJnicuiii(iHifoniii>;'> (B) Why is<S'. mey iliac - 

 foniiin always ? ? Still more puzzling to deal with are the facts of 

 distribution. N. icIincmnoniforDiis covers Europe, Algeria, Asia Minor, 

 Syria, Northern Asia. iS. chrysidifoniiis is confined to western Europe. 

 If S. meyillaeforiiiis be really a hybrid it can only exist on the ground 

 common to both parent species ; but S. iiieyillaefonnis is reported to 

 occur in southern France, Bavaria, Saxony, Greece, the Urals, Altai, &c., 

 in districts quite outside the range of at least one of the stated parent 

 species. Another suggestion of course arises. Is the nieyillac- 

 foniiis of Delahaye something entirely dift'erent from the meyillac- 

 foriiiis of the Altai, Urals, Greece, &c.'? It is, of course, quite beside 

 the question, but we should like to know whether (xcnista tinctoria has 

 hitherto been recorded as a food-plant of N. ichncitiiionifonnis. 



Notes on the distribution of the British Coleoptera. 



By W. E. SHARP. 

 [Continued from p. 149). 

 In any consideration of the present distribution of our British 

 coleoptera, one of the first points to arrest the attention of the enquirer 

 will be that a careful distinction must be drawn between species whose 

 presence here is strictly natural and those which owe their introduction 

 either directly or indirectly to the agency of man ; for it is obvious 

 that any evidence of derivation which the latter can afi:brd is quite 

 useless to the present enquiry. Among our British beetles there are 

 many such, but again we must distinguish. A species may be intro- 

 duced in a non -natural way, i.e., through human agency, whose general 

 economy and environment are strictly natural, that is absolutely 

 independent of human modification of natural conditions, or a species 

 may have so altered its economy and relations to environment as to be 

 quite dependent on such conditions, and, in fact, incapable even of 

 continued existence apart from them. I believe that there are reallv 

 very few instances of the first kind among the Insecta. I doubt 

 whether there is a single well-authenticated case in coleoptera. No 

 doubt there are many such iniiniyraitts: when we consider the enormous 

 facilities which for several years past have existed for the transmission 



