February, '16] mccolloch and hayes: solenopsis molesta 31 



Although isolated nests are frequently found in the open, or under 

 rocks, this species seems to prefer building compound nests with other 

 ants which they rob of their eggs, larvse, and pupae. It is not impos- 

 sible, as is supposed in the case of Solenopsis fugax Lat., that these 

 isolated nests of molesta may be connected with nests of other ants 

 in the neighborhood by long underground galleries. It is by this 

 hypogseic mode of travel that workers find and devastate fields of 

 sorghum. 



Isolated and compound nests are composed of small chambers whose 

 walls are hardened and packed. They are connected by small gal- 

 leries which, in compound nests, ramify through the workings of the 

 colony of larger ants. The minuteness of these galleries prevents the 

 larger ants from molesting the small invaders who forage with com- 

 parative safety. 



Wheeler (15) reports Solenopsis molesta living in lestobiotic relation- 

 ship with the following ants: Pachycondyla harpax F&hr., Odontomachus 

 cZariis Roger, Camponotus fumidus var. festinatus Buckley, Camponotus 

 maculatus subsp. sansabeanus, Formica sanguinea subsp. rubicimda var. 

 subintegra Emery, and different species of Formica, Lasius, Stenamma, 

 and Myrmica. Forbes (17) records Solenopsis molesta living in har- 

 mony with Lasius niger americanus Emery. 



In our work we have taken molesta in colonies of Iridomyrmex pruino- 

 sus Roger var. analis Andre, Cr^mastogaster lineolata var. punctulata 

 Emery, Ponera inexorata Wheeler, Pheidole sp., and Leucotermes lucifu- 

 gus Rossi. 



In artificial nests Solenopsis molesta and Cremastog aster lineolata are 

 decided enemies. The larger ants will bite and sting the smaller ants 

 until they are exterminated but not, however, without a severe strug- 

 gle in which the smaller ants bravely bite the legs and antennae of the 

 attacking giant. A compound colony of Iridomyrmex pruinosus and 

 molesta was kept in an artificial nest without either being disturbed 

 by the other. Each took up quarters in opposite sides of the nest. 



In natural formicaries, winged males and queens appear in July. 

 No data have been obtained on the mating flight. In artificial nests, 

 queens were never fertilized. Tanquary (23) reports a mating flight 

 in Boston as occurring September 5 at 5.00 p. m., and September 8. 

 In artificial nests, queens unattended by workers will rear and care 

 for the young. From this fact we can assume that, after fertilization, 

 queens are able to establish new colonies without the aid of workers. 

 In populous nests as many as nine fertile queens may be found. 

 Table II gives the composition of a number of nests that have been 

 examined. 



