Dog day cicada or harvest fly, Tibicen tibicen Linn. 



1 Adult 



Periodical cicada, Tibicen s e p t c n d e c i m Linn. 



2 Adult 



Alder blight aphid. Pemphigus t e s s e 1 1 a t a Fitch 



3 Portion of alder twig badly infested 



4 Twig infested with young 



a 430 



