Skdkberty 





HACKBERRY MAMMA -GALL. PsyUa celtides- mamma. RILEY. 

 (HEMIPTERA. PSYLLID^E.) 



The Psylla cdtides-mamma is the only insect found upon 

 the leaves of Hackberry tree. Prof. C. V. Riley has 

 described the insect in Johnson's Encyclopaedia as follows : 



"The Psylla form 

 galls of various 

 shapes and sizes on 

 the stems and leaves 

 of Hackberry (Cdtis). 

 In life - habits they 

 differ from all the 

 other gall-insects,and 

 agree with their near- 

 est relatives, the 

 plant - lice, only in 

 being the architect of 

 their own galls. The 

 egg glued in spring 

 to tender leaf or twig 

 soon hatches, and 

 under the irritation 

 caused by the young 

 Psylla, the^gall soon 

 imbeds it. Within 

 this gall the insect 

 dwells till it has ac- 

 quired the pupa state, 

 which is generally by 

 the time the leaves 



of gall enlarged, showing insect within; c, pupa, begin tO tum and 

 greatly enlarged, showing spines at tip of body, by i m i i 



which the gall is perforated for escape. drop. 1 D 6 n, by 



means of certain horny spines or thorns at the end of its 



HACKBF.RRY MAMMA-GALL, (made by Psylla celtides 

 mamma); a, leaf with galls, natural size; 6, sectio 



