1906.] 



The Large Larch Sawflv. 



391 



ends ; the inside is smooth, the outside shows a raised network 

 pattern. The size may be taken on the average as between 

 I inch and ^ inch. I have some from the soil less than | inch, 

 but these may contain parasitized larvae. 



In answer to inquiries I give below tables which may assist 

 in making certain the determination of the large larch sawfly. 



Sawfly Caterpillars. 

 Head globular. 



Moth Caterpillars. 

 Head somewhat hollowed out and not so 

 globular. 



A group of ocelli on each side of the 

 head. 



Hooklets on the abdominal legs. 



Legs 16 in number or less. 



The Geometer moth caterpillars, of 

 which at least three species feed on 

 larch, have a less number of legs 

 than 16. The caterpillars of the 

 larch mining moth (this was quite 

 common in Cumberland, and is 

 often a serious enemy of the larch) 

 mine into the needles, causing the 

 upper half to shrivel up ; these 

 caterpillars are "very minute, and 

 make ca^es for themselves in 

 hollowed out parts of the needles. 



The Large Larch Sawfly. 

 NeniaiMS Erichsofii. 

 Adult 10 mm. in length, and with red 



on the abdomen. 

 Thorax prominently and thickly punc- 

 tured. 



The eggs are laid on the young shoots. 

 Caterpillar measures up to 22 mm. and 



is grey-green on the back, lighter on 



the sides. 

 Head of caterpillar black. 

 Caterpillars eat till the end of August. 

 The caterpillar eats especially the leaf 



clusters or tufts. 



One ocellus on each side of the head. 



No hooklets on the abdominal legs. 

 Lees more than 16. 



Genus Lophyrtis. 



^.o-.,the pine sawflies, 

 not found on 

 larch. 



The caterpillars have 

 22 legs. 



Genus Nematus. 



The caterpillars 

 have 20 legs. 



The Small Larch Sawfly. 

 Neviatits laricis. 

 Adult 6 mm. in length and quite black. 



Thorax not prominently punctured, and 



may be quite smooth. 

 The eggs are laid on the buds. 

 Caterpillar measures up to 15 mm., and 

 is grass-green or greenish-brown. 



Head of caterpillar brown. 

 Caterpillars full grown in July. 

 The caterpillar eats more commonly the 

 single leaves on the shoot of the 

 current year. 



Life Flistory and Habits of the Large Larch Saivfiy. — The 

 caterpillars winter under cover of the cocoons and pupate, 

 generally speaking, in May or June, according to the conditions. 

 I know of no records in Britain giving dates of the appearance 

 of the adults, but probably they issue in June. The eggs are laid, 

 in one or two rows, on the youngest larch shoots, and in slits in 

 the bark made by the saws. Packard saw the eggs laid at the 

 bases of the young leaves. (It will be recalled that on the new 

 shoot or shoot of the current year in the larch the leaves are not 

 in clusters but are arranged singly.) The presence of the eggs 

 may cause the shoots to curl somewhat, and on occasion the 

 leaf at whose base an egg has been laid, dies. Packard * 



•s Fifth Report of the United States Entomological Commission : " Poorest Insects." 

 1890. 



