1921.] 231 



from the apex and all the rest on both sides of the middle being 

 eaten away. 



Oviposition. — On May 29th, when the J^oung larvae were fu'st seen, 

 it became clear how the eggs are placed. After the hatching of the 

 larvae the edges of the leaf -tissue round the emergence-holes turn broAvn, 

 rendering the holes easy to see, though careful search had failed to I'eveal 

 the eggs in the leaves before hatching. Two leaves showing groups of 

 emergence-holes were dried and preserved. These holes, where larvae 

 have emerged on hatching, are situated in groups on the flat surfaces 

 of some of the shorter outer leaves (leaves about 9-12 inches long, the 

 first in the season to develop), and were hidden low down among the 

 taller younger leaves and flowering stems. In the two leaves preserved 

 all the holes are on one face, and they are scattered over 2-3 inches of 

 the length of the leaf near its base. They are irregularly placed, at 

 distances from about j^ to f inch (about 3 to nearly 10 mm.) apart. 

 There are 12 or 13 such holes in one leaf, 5 in the other. They lie along 

 the thickened middle part, but there are some other holes nearer the 

 edge, which may either be egg-holes or places where the new-hatched 

 larvae have eaten the leaf. Careful examination failed to reveal any 

 indication of eggs having been laid in the flowering stems of the plant, 

 which, moreover, were not grown up at the time when signs of egg- 

 laying were noticed. The oviposition is therefore quite different from 

 that of the closely related Phymatocera aterrima, which lays its eggs in 

 a very close, regular, longitudinal series in the stems (not leaves) of 

 Solomon's Seal, Polygonatum (F. D. Morice, Proc, Ent. Soc. London, 

 1911, pp. clxiv et sqq. and pi. 1 ; and T. A. Chapman, op. cit.). 



As regards other occurrences of the Iris Sawfly in this country it 

 can be added that on May 14th, 1921, I saw several adults sitting on a 

 clump of the yellow iris at Fulbourne, about 5 miles from Cambridge, 

 but no traces of eggs or larvae were visible : and on July 19th, 1921, 

 some full-sized larvae were found by a party of students on the banks of 

 the River Lark at Mildenhall, Suffolk. Mr. Morice tells me that Mr. 

 Collin found it a few years ago in his garden at Newmarket ; that it 

 occurs all over the Woking district each spring ; that it has been sent to 

 him from Cheshire ; but that he has not yet had it reported from 

 Hampshire, though one or two careful observers of sawflies have looked 

 for it in that county. 



The normal food-plant of the insect appears to be the yellow flag- 

 {Iris j^seudacorus), but Mr. Morice informs me that according to> 

 Enslin it will feed on other species of Iris in gardens, and he himself 



