Proceedings. 1924 39 



Eacli iiiii;raiit dejidsits six (ir scvrii scxcil iiiilividiials. whirli, as i-liar- 

 acti'ristic (if the sexual fiinus (if tliis uciius ai'c witlidiit functidiiiuji- iiiinitli 

 |)ai'ts. 



These males and females li\-e foi- ahdut a week hidden in the ereviees 

 (if the hark and amongst the damp nuiss (if the trunk. Fdur moults take 

 place hefore mating, after whieh (iperation the male soon dies. The 

 female lives for a day or two and may or ma\- Udt extrude her single e<xff 

 hefore death. Eggs may often be found appai-ently healthy, with the 

 shrivelled skin of the mother still adhering. 



The sexes are without wooly secretion, jiale straw in eohir, the males 

 smaller and dai-ker than the females, whieh measure 1 mm, in length; 

 the males being only one-half mm. hmg. 



The egg is elongate, abdut .(i mm. hmg, pellucid when laid, becoming 

 straw yellow by spring. The eggs are not attached to anything when 

 laid, but are sim])ly (lepositiMl in crevices amimgst the nidss stems. 



EcdXdMic Imimiktaxci: and ("(IXTROI,. 



This insect has udt jiroved to he of seridiis ecfuiomic imiiortance so 

 far in America, It is, Imwever, repdrted by Theobald as doing serious 

 damage to young currants in the nursery row in England, 



In the event of its increasing to serious extent, the following observa- 

 tions may be useful: 



In the control of this insect on its ])i-iniary host, the elm, the most 

 vulnerable period appears to be when the fall migrants are clustered on 

 the trunks, depositing the sexes there. At that time even one application 

 (if nicotine sulphate would undoubtedly destroy a very large percentage 

 of this migration, and two a])plications ten days apart would undoubted- 

 ly destroy almost the entire number, 



Wliere elms hav(» been rendei'cd uiisighlly by leaf curls made either 

 by tliis s|)ecics (ii- dther Eriosomas, as often occurs, the above procedure 

 siiduhl be folldwed, 



Tlu' leaf cui-ls are almost impenetrable by si)rays, and, with tlie 

 additional protection the lice receive fi-om their waxy secretion, they are 

 very difficult to destroy at this stage in their life-history. 



Experiments were conducted at Agassi;^ in 11121 with soil insect ieidcs, 

 such as carbon bisulphide, naphthalene, nicotine sulphate, but all failed 

 through lack of penetration, and whereas the subterranean forms descend 

 several feet, it would a]")pear economically imjiossible to treat the roots of 

 small fi'uils thus. 



In 192;5 an experiment was cdnducted with naphthalene as a deter- 

 rent, the object being to ]U'event the deposition of the root form by the 

 spi'in^ migrants. 



