MAINE) AGRICUIvTURAI, EXPERIMENT STATION. I9I3. 39 



BB. Terminal leaf cluster or rosette on Ulmus amcr- 

 icaiia. Spring migration to apple, mountain ash, 



and hawthorn. Maine to Colorado 



S. lanigera (americana in part, of authors) 



BBB. Leaf curl or roll type of deformation. 



C. Leaf roll. Wax glands of apterous generations and 

 antennae of winged generations apparently the 

 same as those of the rosette dweller. Spring mi- 

 gration to apple. Recorded as yet only from the 

 south S. lanigera (americana in part, of authors) 



CC. Leaf roll of Ulmus scabra and U. campestris. An- 

 tenna of winged generations with V and VI with- 

 out annulations. Spring migration to gooseberry 

 and currant. European species. In America 

 found in California, Oregon and Maine (1913) 

 S. ulmi (fodiens) 



CCC. Leaf roll of Ulunis americana. Second apterous 

 spring generation with wax glands distinctly un- 

 like those of lanigera. Spring migrant with 

 antenna typically with III not longer than 

 IV-|-V-|-VI. Alternate host unknown. Maine to 

 California S. americana in part, of authors 



LEAE HOPPER INVESTIGATIONS. 



The insects known as leaf hoppers belong to the same order 

 of insects as the aphids or plant-lice and like them feed by 

 piercing the plant tissue with a sharp beak and sucking the sap. 

 As their name implies, however, they are not stationary like 

 the aphids but hop actively from place to place so that often 

 the damage done by them is hard to trace to its source. Espe- 

 cially is this the case when as often happens fungous troubles 

 find entrance into the plant tissue at the wounds caused by the 

 insects. 



Closely allied to the leaf hoppers and included with them to 

 a certain extent in this account are the "frog hoppers" or 

 "spittle insects" known by the blobs of froth, common in 

 meadows and on trees in which the young live. 



Most of the species are very inconspicuous both on account 

 of their small size and their close color resemblance to the ob- 

 jects around them. They jump so quickly when disturbed that 



