2 ALDEB. 



The attack of the Alder Clear wing has long been known on the 

 Continent as injurious both to Alder and Birch ; but with us the 

 appearance even of the moth has been recorded, in our standard works, 

 as seldom being observed ; and (so far as I am aware) until the past 

 season no observations of the method of attack have been taken here, 

 nor has it previously been noticed as occurring to an injurious extent. 



In Stephens' ' British Entomology,' this Clearwing is mentioned 

 as an insect so decidedly rare that the writer had only seen five indi- 

 genous specimens ; and Prof. J. 0. Westwood notes that " it is very 

 rare in this country." * In Stainton's ' Manual,' vol. i, p. 100, it is 

 observed that this species {T. spJuFgiforme) is at large towards the 

 middle or end of May, and in June ; but that " being so great a rarity," 

 he cannot give directions where it may be found ; and with regard to 

 the habitat, he merely mentions (p. 105), " Lives in stems of Alder." 



When, however, it does effect a settlement, the instance of last 

 season shows that it has such a power of causing mischief here, as 

 well as on the Continent, by means of its caterpillars boring up young 

 Alder stems, that it is quite qualified to hold a place amongst our 

 seriously injurious insects. 



I had not myself ever received any observations regarding this 

 " Alder," or " White-barred" Clearwing Moth, until the beginning of 

 May in the past season, when I was favoured with the first of a series 

 of communications by Lieut. -Gen. Sir J. Hills- Johnes, V.C., K.C.B., 

 of Dolaoothy, Llanwrda, S. Wales, regarding mischief caused by this 

 attack in one of his Alder plantations, together with specimens of the 

 infested stems containing the chrysalis, from which I was able to rear 

 the moth (as figured at heading). 



In the first observation, received about the 2nd of May, it was 

 mentioned, " The young Alders were planted two years ago, and 

 looked very healthy last year till close to the end of the season, when 

 they began to droop, and my woodman found this grub just where the 

 tree issued from the ground " (J. H.- J.) ; and on the Gth of May further 

 specimens of the young Alder, then being destroyed by the attack, 

 were forwarded, the grub being then alive within. 



In such of the points as were then observable, the method of injury 

 agreed with that described by Dr. Bernard Altum f as occurring in the 

 case of Continental attack, as follows. — " This Sesia lives by prefer- 

 ence, whilst in larval state, in young Alder stems ; but it infests the 

 Birch also. It is to be found in June (the time of flight) near these 

 trees, hovering low down, or on the foliage. They appear not to be 

 rare anywhere in our country." .... The life-history is thus 

 described: — " They lay a single egg, deep down, at the root-knots of 



* See Humphrey and Westwood's ' British Moths,' vol. i. p. 140. 

 t 'Forst Zoologie von Dr. Bernard Altum, Insecten,' ii. p. 41. 



