NOTES ON THE WOOD-WASPS CSI/^E.Y) IN SCOTLAND i77 



with two females with black antennae from the same timber, 

 which are clearly noctilio. Though 1 have examined about a 

 score of specimens from different parts of Scotland, all except 

 these four I now refer to cyaneus. In this connection it is 

 fortunate that I possess two of Service's specimens (females) 

 taken at Munches, Kirkcudbrightshire, so long ago as 1883, 

 and they prove to be cyaneus ; so that this species (which by 

 the way is of American origin) has been in the south of 

 Scotland for at least forty years. The three forms are very 

 closely related and the question of their specific status is still 

 in doubt. It appears to me that breeding experiments alone 

 will settle the matter. That cyaneus is the common species 

 in the pine-woods of Scotland is the opinion of Mr K. J. Blair 

 of the British Museum, expressed in a letter written in 

 September 1921 to Mr J. Ritchie, Curator of the Perth 

 Museum. I may add that I have compared my series with 

 a male and a female determined by Mr Blair for the Perth 

 Museum, and with the exception of the noctilios above 

 mentioned, the females have the relatively longer saw- 

 sheath and narrower terminal spike of cyaneus^ as shown in 

 Mr Morice's plate in the Proceedings of the Entomological 

 Society of London for 1917 (pp. xxi. and xxii.). The male 

 of cyaneus has the eighth dorsal segment entirely reddish- 

 yellow, while in noctilio it is blue-black ; ^ and it looks to me 

 as if the hind tibia of the former is relatively longer than the 

 first tarsal joint, when seen alongside the leg of the male of 

 the latter. Further, as I am informed by Mr Morice, the 

 first brachial cross-vein in the fore-wing is always complete 

 in cyaneus^ whereas in noctilio it is frequently incomplete. 

 On the whole I am inclined to regard cyanetis as an American 

 sub-species of the o\d-\vor\djuvencus. Of the latter, however, 

 I know nothing personally. As hetv^etn juvencus and noctilio, 

 Enslin^ expresses doubt as to their distinctness, and accord- 

 ing to him, intermediates exist. To me the separation of 

 noctilio and cyaneus appears to present little difficulty. 



Great variation in size occurs in the Siricidce; a female of 



^ In this respect cyaneus is stated to agree -wiXhjuvencus. 

 2 In "Die Blatt- und Holzwespen" (Schroder's Insekten Mittel- 

 europas," 1913). 



131 AND 132 Y 



