243 



brood emerged late in the autumn. As conditions at this time were 

 unfavourable, it is possible that a third brood may normally occur. 

 The "winter was passed in the pupal stage, the cocoons all being attached 

 to the twigs. Adults emerged from April until 6th July. Larvae of 

 the first brood were observed to feed on the old leaves, while those of 

 the second brood attacked the new leaves which had reached maturity. 

 Early-hatched larvae of the first generation pupated about the middle 

 of June. Second generation larvae fed during August and September. 

 The average duration of the larval stage was 30| days. The species is 

 markedly parthenogenetic, the larvae from unfertilised eggs being able 

 to develop into hibernating pupae. L. pini is attacked by certain 

 American species of parasitic Diptera and Hymenoptera, including 

 the Chalcid, Pachyneuron {Dibrachys) nigrocyaneus, Norton, the 

 Ichneumonid, Hemiteles utilis, Norton, and the Tachinid, Exorista 

 petiohta, Coq. A bibliography is appended. 



Britton (W, E.). The Larch Sawfly, Lygaeommatus (Nematus) 

 erichsoni, Hartig. — Rept. Connecticut Agric. Expt. Sta., 1915, New 

 Haven, 1916, pp. 125-134, 2 plates. [Received 25th April 1916.] 



Lygaeonematus erichsoni was recorded from several localities in 

 Connecticut during 1915. The insect has also caused injury in 

 Massachusetts, Maine, New York and south-eastern Canada, as well 

 as in Germany, Switzerland, Holland, Denmark, Sweden, Finland 

 and Britain. The food-plants are Larix americana, L. europaea, 

 L. leptolepis (Japanese larch) and L. sibirica ; in Pennsylvania 

 attacks on hemlock have been reported. Injury to the foliage is 

 caused by the deposition of eggs by the female and by the feeding 

 habits of the larva. There is probably a single brood annually. The 

 winter is passed as a larva inside the cocoon and pupation occurs in 

 the spring. The eggs are laid during May in Ontario, and are inserted 

 in the terminal twig, with the result that the twig is killed or per- 

 manently injured and distorted. The larvae, which hatch in from 

 8 to 10 days, feed on the leaves and may cause the complete defoliation 

 of closely-planted trees. Isolated trees are able to recover in most 

 cases, owing to more favourable conditions of light, air, and moisture. 

 The reduced vitality of partly or entirely defoliated trees renders them 

 liable to attack by bark beetles, notably by Dendroctonus simplex, Lee. 

 The duration of the larval stage varies from three to four weeks. 

 Pupation occurs at the base of the tree, either in the soil or on the 

 surface beneath litter. Reproduction is parthenogenetic to a very 

 great extent. 



The natural enemies of L. erichsoni include the meadow mouse and 

 deer mouse, several kinds of birds, parasitic and predaceous insects 

 and a fungus. The Ichneumon, Mesoleius tentJiredinis, Mori, is 

 parasitic on the sawfly in England and has been introduced and liberated 

 in Canada. The Chalcid, Coelopisthis {Pteromalus) netnaticida, Pack., 

 occurs in Massachusetts and probably also in Connecticut, and acts 

 as an important check. Dighchis sp. parasitised from 10 to 15 per 

 cent, of cocoons in Minnesota in 1909-10 ; while Perilampus sp. and 

 Microgaster sp. have been reared from pupae in Wisconsin and New 

 York respectively. In England, the following parasitic Ichneumons 

 have been reared : — Microcryptus labralis, Grav., Aptesis nigrocinctoj\ 

 Foers., Spilocryptus incubitor, Strom., Coelichneumon fuscipes, Grav., 



