ALDER CLEARWING MOTH. 8 



little Alder stems of only about three centimetres in diameter. In the 

 first summer the caterpillar ravayes * these beneath the bark ; it 

 bybernates ; and in the second summer gradually makes its way 

 upwards by a straight feeding-gallery." — (B. A.) 



The above account gives an excellent description of the condition 

 of the Alder stems sent me. These were upwards of lialf-an-inch 

 across, and where the attack had run its course for two seasons, the 

 stem was deeply gnawed at the base beneath the bark so as to ring it, 

 or destroy it still more deeply. From this injured base the grub- 

 channel started straight up the stem. This tunnel was from three to 

 four inches in length, and from an eighth to a quarter of an inch in 

 breadth, and took a straight, or only slightly deviating, direction 

 upwards, until at the highest extremity it curved to one side and 

 opened out in the side of the Alder stem (see fig. p. 1), giving the exit- 

 hole for the future moth. 



In some cases a disaster appears to occur to the growing caterpillar, 

 for, in one specimen stem, the tunnel had been successfully worked out 

 up to the commencement of the curve for the opening aperture, but there 

 operations had stopped, and the deceased tenant, now dried up, though 

 still showing a strong, horny, chestnut-coloured head, and darker jaws 

 and front of face, was lying shrivelled within. 



The large quantity of " frass " (that is, of brownish powdery matter 

 resulting from the caterpillar feeding in the wood) was very noticeable. 

 This filled up much of the lower part of the upright tunnel figured (p. 

 1), and was observable amongst the ravages at the base of the stem. 

 It was also observable at the base of one stem, where, presumably, as 

 yet only one summer's injuries had been carried on, as the wood just 

 beneath the bark had been channelled and gnawed round; but the 

 upright tunnel had not yet been started. 



The method of infestation was described shortly, but with all 

 requisite clearness, from his own local observations, by Sir J. Hills- 

 Johnes. The attack is started by egg-laying at the root, at the 

 junction of the stem and ground ; and the caterpillar in due time 

 turning into the chrysalis condition, appears as a fly, emerging from a 

 hole up in the stem. The observer noted that occasionally two tunnels 

 were to be found in one stem. 



The first specimen seen in the act of emergence by Sir J. Hills- 

 Johnes was observed on the 3rd of June ; the specimen figured at p. 1 

 was observed by myself on the 6th of the same month as recently 

 emerged from the chrysalis sent from Dolacothy. 



• The German word " platz " expresses vehement action, as, to crush, crack, 

 burst, or, in popular application, " to observe no medium " ; therefore I have 

 thought that the word " ravage " would convey the absolute destruction wrought by 

 the caterpillar, and well shown by the specimens sent to me. — E. A. 0. 



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