1^1 



oped than in former generations, and the eyes are simpler. The 

 general form of a female of this generatit>n is seen at c, figure 65. 

 After a siiort time the bright yellow, which at first characterizes the 

 insect, becomes paler, the skin meanwhile being cast off, and though 

 at first smooth and glossy, the surface of the body becomes dusty or 

 powdery. The females, which are larger than the males, are about 

 fifteen hundredths'of an inch long. As may be seen in figure tj.'), c. 

 the female as she grows has a single Q^^^!,., developed within the 

 abdomen; its outlines can be indistincllv made out. Soon after 

 pairing both sexes perish, leaving in the crevices or under scales of 

 the bark the eggs more or less covered by the dried and shriveled 

 skin of the parent, and thus they remain through the winter to 

 develop in the spring into new "stem-mothers." 



Schizonciira //Iifi/\ Linn. 



Is a very similar species, and infests European elms. "Phis spe- 

 cies has undoubtedh' ]:)cen confoinuled with the preceding, but it 

 ditl'ers in some important res[)ects, such as that the stem-mother of 

 the last named species settles on the upper instead of the under 

 side of the leaf. The galls arc different, the wings seem to be 

 longer, and the veining is somewhat difHerent. Still the two spe- 

 cies certainly approach each other very closely. 



Schizofiezwa Rilcy/\ Thomas. 



Is a species common in some sections of the country, and no- 

 ticeably different from the other species that attack the elm, and 

 in the character of the injury whicii it inflicts. It is described 

 under the name of Rriosoma uhni^ by Dr. Riley in his First 

 Report on Insects of Missouri ; but Dr. Thomas in his mono- 

 graph of the family, in Vol. IG, Transactions Department of 

 Agriculture, Illinois, states that Riley's name is preoccupied 

 by one of Linneus. The winged form is dark blue, about a 

 tenth of an inch hnig, with long transparent wings. The Noung- 

 er, wingless forms are lighter, and sometimes are of a reddish 

 shade. From the cottony or wooly substance which these in- 

 sects secrete Rile\ calls the species The woolv elm tkee loltse. 

 They collect on the tree twigs, branches, or trunk in clusters, and 

 by the visitation of their punctures, produce a gnarled growth. 

 The wool secreted is of the clearest wliite, and wholly covers the 

 body of the insect, and when many are located on a branch they 



