ALEBRA. 101 



our crops, by reason of their irritating punctures on 

 the leaves, which injuries result in small yellow spots, 

 caused by the destruction of the parenchyma. Thus 

 our potatoes and mangold leaves sometimes suffer, 

 and also the ferns in our hot-houses, through similar 

 attacks. Various bushes and forest trees form food 

 and shelter for several species. Occasionally the white- 

 thorn (Cratcegus) is tenanted by thousands of small 

 Typhlocybm, and these cover the clothes of anyone who 

 shakes a bough overhead. Noticeable amongst trees 

 forming their habitats may be named the hazel, the 

 elm, the poplar, willow, alder, and rose tree ; some of 

 which trees have their special and particular species. 



I have followed Mr. J. Edwards' lead as to dividing 

 this group into seven genera. Dr. Sahlberg and other 

 systematists add to these Compsus, Notus, Cicaclula, and 

 Erythria, or at any rate they make them equivalent, if 

 not additive, to the former genera. 



The genera are separable by attention to certain 

 characteristics in the elytral and alar neuration ; and 

 by an examination of the complicated details and 

 appendages of the sexual organs. 



Of the seven genera composing the Typhlocybidse 

 it may be conveniently noted that Alebra, Dicranura, 

 Kybos and Chlorita show their wings each furnished 

 with a marginal vein, complete to the first fork of the 

 anal nerve. The three remaining genera — Eupteryx, 

 Ttjphlocyba, and Zygina — -have no marginal nervure. 



All these genera have three radial nervures, but in 

 the first section these end in the marginal nervure ; 

 and in the second section they end at the periphery of 

 the wing. 



Genus XLIII. —ALEBRA, Fkb. 



Vertex slightly curved, with its fore edge running 

 parallel to the curved hind-margin. Ocelli distinctly 

 visible. Pronotum rather wider than the head. 



