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 



264 



FIG. 263. The oblong leaf-winged katydid (Amblycorypha oblongifolia); (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 (Acronycta oblinita), which feeds upon 

 various forest-margin weeds and shrubs; natural 

 size (after Riley). 



