28 LIFE HISTORY OF THE ALDER BLIGHT APHIS. 



Pag-e. 



Prociphilus, description of genus 6 



tessellata, ant associates , 11 



apterous female on alder, description 23-24 



asexual generations, descriptions 21-25 



colony on leaf of maple, description 20, 21 



description by Fitch 6-7 



of principal stages 18-25 



economic status 25-26 



first series ( Pemphigus acerifolii Riley) 9-14 



generic and specific synonymy 6-9 



hibernating series, description 24-25 



insect enemies 11 



male, description 20 



mention by Kalm as Chermes alni 8-9 



migrant, description 22-23 



notes on alternate series 14-18 



original series 11-14 



second series (on alder) 14-18 



sexual female, description 19-20 



generation, description 19-21 



stem-mother, mature, description 22 



young, description ._ 21 



winter egg 21 



Psylla alni, description by Ratzeburg, on alder 9 



viridis= Chermes alni 9 



Schizoneura tessellata, description by Thomas 8 



= Prociphilus tessellata 6 



Syrphid fly larvae, enemies of Prociphilus tessellata. 11 



Tapinoma sessile, association with Prociphilus tessellata 11,17 



Witch-hazel, food plant of Hamamelistes spinosus 5 



Hormaphis hamamelidis 5 



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