No. 115.] 127 



balls or globules, of various sizes, of a sweet liquid which have 

 been excreted by the aphids. As the young emerge through the open- 

 ing, which spreads apart for their egress, the excretion of the 

 " honey-dew " continues, and, when the trees are badly infested, 

 falls almost in showers to the leaves beneath and to the ground. 

 When the elm is a shade tree upon our streets, the honey-dew may 

 often be seen covering and blackening the pavement beneath it. 

 All the members of this second generation are females and winged. 



A third generation follows these, which do not produce galls and 

 from which we have, later in the season, sexual individuals and 

 the deposit of the eggs in sheltered places beneath the bark, destined 

 to survive the winter and give forth the " stem-mother " the 

 following spring. 



The scientific name of this aphis is Glyphina ulmicola (Fitch). 



So far as known, its galls are formed only upon the white elm, 



Ulmus Americana, and upon the younger trees of the species — 



seldom over twenty-five feet in height. The best account of the 



species that we have is that of Messrs. Riley and Monell, cited below. 



Remedy. — Nothing could be done to check the operations of 

 this aphis during its gall stage. Later, when it deserts the gall 

 and is distributed over the tree, its numbers may be reduced by 

 spraying with soap-suds and quassia water, or with tobacco water. 

 Fortunately it seldom becomes very abundant or destructive. 



Bibliography. — As with many other of our aphides, this species 

 has been obliged to submit to so many changes in name since its 

 original description by Dr. Fitch, in 1859, that it would be difficult 

 to recognize it under its various appellations without the aid of a 

 synonymical table, such as is herewith given : 



Bryoscripta ulmicola Fitch : Trans. N. Y. St. Agr. Soc, xviii, 

 1859, pp. 843-4; 5th Report Ins. N. Y., 1859, pp. 63-4, No. 347. 



Thelaxes ulmicola. Walsh : Proc. Ent. Soc. Phil., i, 1862, p. 304 ; 

 Amer. Entomol., i, 1S69, p. 108, f. 90, p. 224. 



Pemphigus ulmicola. Packard : Guide Stud. Ins., 1869, p. 524, 

 f. 525; Ins. Inj. Forest and Shade Trees, 1881, p. 68 (Colopha). 



Colopha ulmicola. Monell : Canad. Entomol., ix, 1877, p. 102. 

 Thelaxes ulmicola. Lintner : Count. Gent., xliii, 1878, p. 455. 

 Colopha ulmicola. Riley - Monell : Bull. U. S. G. - G. Snrv. 

 Terr., v, 1879, pp. 9-13, pi. 1, f. 2. 



