CHAITOPHOEUS ACERTS. 121 



Chaitophoeus aceeis, Lmn. Plates LXXVIII and 



LXXIX. 



Aphis aceris, Linn., Fabr., Schr., Scop., Kalt., Walk. 



Chaitophoriis aceris, Kocli, Pass. 



Puceron de VErahle, Reaum., Balb. et Signoret. 



Much interest attaches to this insect on account of 

 its remarkable dimorphic forms. These characters 

 are so varied that comparatively recent authors have 

 placed the abnormal insect under a different genus ; 

 and even more, some have suggested that a new family 

 should be formed for its reception between the Aphid^e 

 and the Coccidae. 



It will be convenient first to describe the normal 

 forms of this insect. 



Apterous viviparous female. 



Inch. Millimetres. 



Size of body 0-090 XO'OSO 2-27 X 1*27. 



Length of antennae 0*060 1*52. 



cornicles O'OIO 0-25. 



Dark green, shining, much wrinkled. Head broad, 

 olive-green. Vertex flat, furnished with two tufts of 

 fine bristles. Thorax wrinkled. Abdomen globose, 

 with numerous setose tubercles ; posterior rings rapidly 

 narrowing to a blunt apex. Cauda inconspicuous. 

 Antennae and legs green. The whole insect setose. 



Some examples may be found entirely black, and 

 some less tuberculose than others. 



Winged viviparous female. 



This insect is very variable both in form and colour, 

 and these varieties show, also, certain differences as 

 regards their economy. 



