Dr Traquair on " Tailless" Trout from Loch Enoch. 221 



of the genus ; indeed, the great contrast which the larvie 

 of Acronyctm bear to each other is a most remarkable fact. 

 In A. Alni tlie body is of an intense purple-black with a 

 series of tranverse oblong blotches of pale lemon yellow — 

 one on each segment ; and along either side there is a row of 

 hair-like appendages, each flattened at the tip into a sort 

 of club. A few of the larvic of A. leporina — also a good 

 insect — were obtained by beating birches. Here the body — 

 which is of a delicate pea-green — is densely covered with 

 long silky hairs of a beautiful canary yellow. Unfortun- 

 ately, the author had to leave the forest before tlie famous 

 " Crimsons " — Catocala ^Jromissa and C. sponsa — made their 

 appearance. He had scarcely left when C. promissa came 

 forth, and by-and-by C. sponsa abounded. A boxful was 

 received from the son of one of the foresters. 



Of other tribes the only species of any consequence obtained 

 Avas Halias quercana — an insect as beautiful as it is rare. Two 

 specimens only were observed. 



XVII. On Specimens of " Tailless'^ Trout from Loch Enoch, in 

 Kirlccudhrightshire. By Dr R. H. Traquair, F.R.S. 



(Read 18th January 1882. ) 



At the meeting of the British Association at Edinburgh in 

 1871, Mr C. W. Peach exhibited specimens of a peculiar 

 variety of the common trout from Loch na Maorachan in 

 Islay, characterised by an apparently abortive condition of 

 the caudal fin, which had gained for it the popular name of 

 " Tailless Trout." Professor Turner and Mr Peach having been 

 kind enough to supply me with a few specimens of this 

 abnormal form, I published a description of its structural 

 peculiarities in the sixth volume of the " Journal of Anatomy 

 and Physiology." By referring to this paper it will be seen 

 that the most salient peculiarity of the so-called tailless trout 

 of Islay is the condition of the rays of the caudal fin, " wliich 

 are abnormally shortened, are coarse at their extremities, and 

 deficient as to amount of dichotomisation and number of 

 transverse joints; besides which they also show a tendency 



