MOIST FOREST MARGIN 



267 



willow in spring (Fig. 267). Sawfly larvae are common; the large light- 

 colored one (Cimbex americana) (179) has habits of special interest. The 

 female, which is a wasp-like insect, deposits her eggs on the under sides 



of leaves. Blisters are formed, and a 

 young larva lives for a time in each 



263 



264 



Fig. 263. — The oblong leaf-winged katydid (Amblycorypha oblongijolia); (after 

 Forbes) natural size. 



Fig. 264. — The fork-tailed katydid (Scudderia furcata) (after Lugger from 

 Forbes) ; natural size. 



of these. Later it is to be found living freely on the leaves. It usually 



rests with the posterior segments wrapped around a petiole or twig. 



Pupation takes place in a 



silken case. The spotted 



sawfly larva (Pteronus 



ventralis Say) (179) is less 



common. 



Beetles are common 

 on the willow. The leaves 

 are eaten by May-beetles 

 (189) and several leaf-feed- 

 ers (Calligrapha and Lina 

 are common). Several 

 borers attack the twigs 

 (Saperda concolor). Galls 

 are very numerous. The 

 trunks of small willows are 

 commonly attacked by the 

 larvae of the introduced 

 snout-beetle (Cryptorhyn- 

 chus lapathi), and the 

 goat-moth larva {Prionoxystus robiniae Peck.), which bores in the heart- 

 wood. The sap which exudes attracts many sap-beetles (Nitidulidae) . 



Fig. 265. — The adult and larva of the smeared 

 dagger-moth {Acronyda oblinita), which feeds upon 

 various forest-margin weeds and shrubs; natural 

 size (after Riley). 



