148 WILLOW. 



The specimen sent agreed even to almost (if not quite) the minutest 

 particulars with the description of the larva of the Nematus salicis given 

 by Mr. Cameron, and the coloured figure after Brischke.* The peculiar 

 colouring of the caterpillar makes it very noticeable ; the head being 

 black ; the first three segments, and also the last of some tint of 

 orange, and the intermediate segments bluish green. Along the body 

 are seven rows of black points or spots, which are sometimes counted 

 as nine where the two black spots on each segment, between the dorsal 

 and first side row, are also counted as forming a row on each side. 

 The spots, or points, are fewer on the orange segments, and over the 

 tail is a large black spot. " The thoracic legs are marked with black, 

 the claws being of the same colour." It may perhaps be of some ser- 

 vice to remark in passing that "Sawfly" caterpillars are commonly 

 distinguishable from caterpillars of butterflies and moths by the much 

 greater number of their prolegs, or sucker-feet, so that altogether, 

 counting claw-feet and sucker-feet, there are commonly from eighteen 

 to twenty-two legs. In the genus Nematus the larvae have twenty or 

 eighteen legs ; in the case of the TV", salicis I am not perfectly sure of 

 which number it is possessed, but I think it is twenty. 



Where the larvae are numerous, as occurs on the Continent, they 

 are described by Kaltenbach as feeding voraciously on the leafage of 

 various kinds of Willows ; and it is mentioned by Dr. Kitzema Bos 

 that there are two to three broods in the year. The cocoon is formed 

 in the ground, so that where attack has been troublesome, lightly 

 disturbing the surface of the soil so as to skim off the top down to 

 where the cocoons lie and destroying them in the infested earth, would 

 much lessen coming attack. 



As this iV". salicis does not appear to be very common in this 

 country, it has seemed worth while just to allude to its presence ; but 

 so far as I am aware it was only seriously destructive in the one 

 locality named. 



Other kinds of Sawfly attack were also present on Willow, of which 

 specimens were forwarded to me, but which I have not entered on at 

 length, as they were not of special importance. In practical work 

 these infestations are generally observed in larval state, or are drawn 

 attention to by the peculiar method of injury, or by the growths some- 

 times caused, as for instance, the green or rosy galls sometimes found 

 in great numbers on Willow leaves. 



The special kind of Sawfly causing each kind of attack is often not 

 noticeable without much watching; amongst other reasons, because 

 when the grubs are large enough, or the galls large enough, to be 



* See *Mon. of Brit. Phytophagous Hymenoptera,' by P. Cameron (Eay Society), 

 Vol. II., pp. 163, 164 ; and Plate VII., fig. 9, in Vol, I. 



