152 



With Apbids and Coccids, which are covered with an abundant waxy 

 secretion which can not be readily brushed away, we have adopted the 

 plan of melting the wax. We place the insect on a bit of platinum foil 

 and pass it once over the flame of the alcohol lamp. The Avax melts at 

 a surprisingly low temperature and leaves the insect perfectly clean for 

 study. This method is i)articularly of use in the removal of the waxy 

 cocoon of the pupte of male Coecidoe, and is quicker and more thorough 

 than the use of any of the chemical wax solvents which we have tried. — 

 L. O. H. 



THE RELATION OF ANTS TO THE CORN APHIS. 



In the August number of the American Naturalist Professor Corn- 

 stock criticises my note* on the Corn Aphis {Rhopalosiphum maidis), as 

 follows: 



After narrating several experiments, clearly showing that the ants collect the plaut- 

 lice and carry them to the roots of the corn, Mr. Webster makes the following remark- 

 able statement : "These observations led me to conclude * * * that ants, of which 

 three species attend these plant-lice, viz, Lasius flavus, Formica schaufussii, and F. 

 fusca, are not in the least responsible for their distribution over the fields, * * *." 

 We do not think the conclusions of Professor Forbes can be set aside in this way. 



My critic will, possibly, pardon me for suggesting that there is noth- 

 ing remarkable in the statement referred to, nor are the observations of 

 any one set aside. The position taken is simply this ; 



The Corn Plant-louse owes its distribution to the winged migratory 

 broods, of whose ultimate destination the ants can have no conception 

 and as little control over their movements. The number of individuals 

 may be largely increased through the influence of ants, but there is 

 nothing to indicate that their influence directs the movemeuts of the 

 winged generation. Nor do we see that the ants are any more account- 

 able for the appearance of these winged females in any particular field 

 than is the farmer who produces the corn responsible for its appearance 

 in foreign markets when he disposes of his crop to a local dealer. 



In our notice we gave observations showing that as soon as a winged 

 viviparous female alighted on a corn plant and was fouud by an ant the 

 latter took her in charge, placing her on the roots of the plant, where 

 her progeny were fostered and cared for ; that this oflspriug constituted 

 the generation which was the most destructive to the corn crop ; that 

 only in cases of dire necessity were these offspring removed, and all of 

 our attempts to force their removal by the application of substances 

 supposed to be distasteful resulted in failures. 



That ants collect the eggs and young of Aphides, carry them to their 

 homes, and even place the young on their food plants, no one can reason- 

 ably doubt. But to say that this proves that the Aphides are wholly 

 dependent on the ants for either their existence or diffusion is rather a 

 sweeping assertion. 



* Report Commissioner Agriculture 1887, pp. 148-9. 



