GALL APHIDS OF THE ELM. 22$ 



1905. Pemphigus tdmifusus. Washburn loth Ann. Rept. of the State 

 Ent. (Washburn 4th) p. V. Fig. 2. Photograph of galls on 

 leaf. 



1908. Pemphigus ubnifusus, Jackson. A Synopsis of the Genus Pemphi- 



gus. Proceedings of the Col. Hort. Soc, p. 204. Bibliography. 

 Brief description. 



1909. Pemphigus ulmifustis, Gillette Jour. Ec. Ent. Oct. Fig. 10, antenna. 



SCHIZONEURA AMERICANA 



Since the excellent account of Riley's so little work has been 

 done with this species that probably a total quotation of the 

 original publication will be more valuable in this paper than 

 anything else which is at present available. It is, therefore, 

 given entire : 



"ScHizoNEURA Americana n. sp.. 

 "(Curling and gnarling the leaves of the White Elm (Ulnius ameri- 

 ~£ana) , forming thereby a sort of pseudo-gall. The curl made by a sin- 

 gle stem-mother in the spring takes the pretty constant form of a rather 

 wrinkled roll of one side of the young leaf, but, according as there is 

 more than one stem-mother, or as several contiguous leaves are affected, 

 the deformation assumes various distorted shapes, sometimes involving 

 quite large masses of the leaves). 



Biological. 



"There is a good deal of irregularity in the time of appearance of the 

 different generations, but the general history of this species, as I have 

 observed it for several years, is herewith given. There is much greater 

 difificulty in fully tracing the life-history of one of these small creatures 

 than might be supposed. They languish in confinement and ill 

 bear handling. To trace their growth and movements in a state of 

 nature requires vigilance and perseverance, and a great deal of time ; and 

 I have been fortunate, in my studies of this and the next species, in 

 securing the patient aid of Miss M. E. Murtfeldt of Kirkwood, Mo., a 

 lady to whom I have already had repeated occasion to express my indebt- 

 edness. 



"If, during the winter, we carefully examine the cracks and crevices 

 of an American or White Elm that was badly infested with this leaf- 

 curling species the previous summer, we shall be pretty sure to find its 

 impregnated egg — a minute, dull-yellowish, ovoid object, about 0.5 mm. 

 long (Fig. 128, a), either free or still more or less eft'ectually covered 

 with the parent's dry skin, which faintly shows the insections that char- 

 acterized the living female. The same spring influences that cause the 

 leaf-buds to swell and open, likewise induce the hatching of this win- 

 ter egg, and the little creature that issues from it instinctively crawls 

 to the more terminal twigs and branches, and settles upon the first ten- 

 der leaflet it meets with. It constitutes the stem-mother, or first genera- 



