Ilomoptera of Cranhrrry Lake Region 53 



and Beech blight become very conspicuous on account of the forma- 

 tion of great quantities of cottony or wooh' covering, the waxy 

 filaments being secreted by special wax-glands of the dorsal part 

 of the body (mainly located on back of abdomen). 



One of the ecologic associations of special interest is found in 

 the very frequent, almost universal, presence of ants attending the 

 colonies of aphids, the ants utilizing the "honey dew" secretion 

 from the aphids as food. The numerous predaceous and parasitic 

 insects assisted by spiders and birds destroy immense numbers of 

 plant lice and thus the enormous reproductive powers of the aphids 

 are counterbalanced and kept down to such an extent that the 

 plants on which they feed have some show of survival. 



Hormaphis pBpyraceae lives on willow birch and corresponds 

 well with the desci-iption of gall by Oestlund. The galls consist 

 of a distinctly corrugated structure between the leaf veins and con- 

 tains numerous dark brown or black aphids. Callipterus hetu- 

 laecolens (alate individuals, and various sizes of nymphs and wing- 

 less adults) were found in some of the galls occurring on yellow 

 birch leaves, but more commonly entirely independent of the galls 

 and evidently in the galls by accident. 



Family CHERMIDAE 



These interesting little insects form a quite conspicuous element 

 in the insect fauna of the Cranberry Lake region, especially Psyllia 

 floccosa, irimaculata on fire cherry, and carpinicola, apparently on 

 numerous host plants, being taken in immense numbers. All the 

 species are leaf feeders, living on the under surface of the leaves. 

 The common gall making species occurring on hackberrj' trees are 

 wanting here as the host plant does not occur. 



A ver}^ striking feature is presented in the white cottony masses 

 covering the bodies of the nymphs in P. floccosa on alder and 

 P. 3-maculata on fire cherry. The latter form may be counted 

 as destructive and merits a more detailed study of life history 

 and ecology for economic reasons. 



Aphalara veaziei Patch. 



Cranberry Lake, July 5, 1920; June 9, 1920. 



Trioza nigrilla Crawford. 



This species is widely distributed and a fairly common species 

 on willows. Cranberry Lake, Aug. 4, 1919. 



Psyllia striata (Patch.) 



I refer here a very abundant species occurring commonly on 

 yellow birch, but as adult found on a wide variety of plants. 

 Nymphs with small fiocculent covering have been noted on birch 

 leaves, but I have not verified the connection. E\ddently very 

 close to carpimvola. Cranberry Lake. July 2-25. 1920. 



