36 JOURNAL OF ECONOMIC ENTOMOLOGY [VoL 2 



Early in September, however, migrants leave the alder in great 

 numbers and as they do not alight upon other alders seem to be lost 

 to any significance for the species. 



Last fall, however, these migrants were present in such countless 

 numbers about the jNIaine Campus that it was possible to ascertain 

 without doubt that they were migrating to the trunks of maples. — 

 preferably Acer dasijcarpum. Ehrh. and an ornamental cut leaved 

 variety of that species. Alighting upon the trunk they sought crev- 

 ices, gave birth to minute forms. — • true apterous males and females. 

 These females without feeding deposited eggs upon the bark. 



This fact explained apparently not only the function of the mi- 

 grants from the alder but the resemblance of Pemphigus tessellata 

 and P. acerfolii, for there seems no place for doubt that the Pem- 

 phigus common upon the leaves of Acer dasycarpum from early 

 spring to mid-July are hatched from the eggs of Pemphigiis tessel- 

 lata deposited upon the maple trunk. 



Additional light upon the identity of these two species may perhaps, 

 be found in a collection of migrants taken on alder leaves in mid- 

 July at the time P. acerfolii is leaving the maple. 



There is no need for taking further time for these comments here. 

 But as this species has been of exceeding great interest to me I have 

 brought specimens of: 



Pemphigus tessellata apterous viviparous forms. 

 Pemphigus tessellata migrants. 

 Pemphigtis tessellata hibernating young. 

 Pemphigus tessellata males, females and eggs. 

 Pemphigus acerifolii migrants. 



These will be here during the session and can be seen by any who 

 wish. 



President Forbes : The paper is now before you for discussion. 



C. L. jMarlatt : Mr. President, I am sure we all are very much 

 interested in this paper by ]\Iiss Patch. She has done a very cred- 

 itable piece of work and has cleared up some facts in the life history 

 of this insect, and thrown light on the general subject. I am sure I, 

 for one, feel very much indebted to her and am very much interested 

 in the work she has already published. I wish also to compliment 

 her on the clearness and brevity with which she presented her paper. 

 It will be a lesson to many of us. 



President Forbes called First Vice-President Britton to the chair. 



