NOTES ON A COLORADO ANT. 77 



there were still some living specimens at each nest. The pupae at the 

 treated nests seemed to be dead and the living ants paid no attention 

 to them. It was observed that at two places quite a number of 

 pupae had been overlooked and not soaked by the solution and at 

 another place a moderate number of winged specimens had crawled 

 from an opening of an untreated (overlooked) nest. 



By September 27 about a dozen small, weak colonies had started, 

 and on the following day between 4 and 5 p. m. all the inhabited nests 

 wore again treated with 25 gallons of the solution at the rate of one- 

 half ounce of 98 per cent cyanid to each gallon of water. In this 

 treatment all the openings in the nests were enlarged with a pointed 

 stick and from a quart to a gallon of the solution poured into each. 

 At this date many of the cantaloupe vines had been trampled down 

 by the pickers or had died from disease or other cause. As a result 

 there was not a very good suppl}' of aphides in the immediate vicinity 

 of the nests and the ants were mostly close about or in the nests. 

 At two places many pupae were present and at another nest there were 

 a good many winged specimens. 



Examination made on the following day (September 29) showed 

 that there were still a few living ants about the nests, and the pupae 

 were still light in color and did not appear to be dead. A day later 

 some of the pupa? appeared to be still aUve, but as all of these were 

 embedded in the moist soil, where the living ants paid no attention 

 to them, they certainly could not have survived. At this time there 

 was no odor of the cyanid over the nests, but when lumps of the 

 moist soil were picked up the odor from them was quite apparent. 



Repeated examinations made of the treated strip during October 

 and November showed that the ants had almost completely disap- 

 peared, while at untreated (check) nests they occurred in large num- 

 bers. It would be interesting to know what became of the few 

 specimens which survived the last treatment. Possibly they became 

 discouraged and went to less troubled quarters. 



It is evident that from experiments of this nature definite or final 

 conclusions can not yet be reached. The work was begun so late 

 in the season that the rather gradual decrease in the number 

 of the ants had no marked effect on the melon aphis. It showed 

 that to keep this species within reasonable bounds repeated appli- 

 cations of the cyanid and constant watching are necessary. As 

 this would require so much more attention than the ordinary farmer 

 can be intluced to give, it does not seem probable that this method 

 will ever become very popular for this particular species of ant, 

 unless it can be definitely proved that this species is a more important 

 factor in the melon-aphis problem than it is now known to be. It is 

 very probable that quicker results would have been obtained if a 

 stronger solution had been used. 



