THE CORN ROOT-APHIS AND ATTENDANT ANT. 29 



tiou F were ample warrant for the holding of a joint session. He 

 thought the plan was one that would probably be advisable to con- 

 tinue in the future. 



The following tAvo papers, taken from the programme of Section 

 F, were then presented. They will be published in full elsewhere. 



THE PROBLEM OF WING ORIGIN AND ITS SIGNIFICANCE IN 

 INSECT PHYLOGENY. 



By Herbert Osborn, ('oliiiiihiis, Ohio. 



[To be pnblislied elsewhere.] 



PRELIMINARY OBSERVATIONS ON THE VARIATIONS OF 

 UTETHEISA VENUSTA DALMAN. 



By Mel. T. Cook, S(niti<t(/o <Ic las Vvyas. Viihu. 



[Absti-Mct. I 



The literature recognizes three species {U. hella, U. vemista.. and 

 U. ornatrix) and three varieties {hyhrida, terminalis^ and stretchii) of 

 this genus. These cover a very wide range. The species and varie- 

 ties are separated primarily on color characters. After examining 

 a very large number of specimens, many of which w^ere reared in 

 captivity, the writer concludes that the intergradations are such as 

 to reduce these three species and three varieties to one species. The 

 writer has also bred and reared a number of these insects, from the 

 study of which he reaches the same conclusion as indicated above. 

 The work will be continued. 



The following paper was presented : 



THE CORN ROOT-APHIS AND ITS ATTENDANT ANT. 



{ApJtis iiKiiili-rddicis Forbes and Lttxiiis iiificr L.. v;ir. aiiicricuinis Emery.) 

 By S. A. Forbes, Urbdim, III. 



Two great dangers threaten tlie perpetual prosperity of the North 

 American corn belt; one, the gradual exhaustion of some essential 

 element of soil fertility, and the other, the gradual increase of insects 

 esj^ecially injurious to the corn crop. Of these two dangers the lat- 

 ter is, I believe, the more immediate nnd the more diflicult to meet. 



It is the more innnediate, first, because the exhaustion of any in- 

 gredient of the soil is a process of subtraction merely, while the in- 

 crease of insects is a process of nndtiplication ; and, second, be(;ause 

 farmers are generally accustomed to return to tlieir farms, iri more or 



