February-, '16] MCCOLLOCH and HAYES: solenopsis molesta 27 



Larger ants like Cremastogaster lineolata Say and Iridomyrmex pruino- 

 sus Roger were kept quite successfully in these cages. 



When the cage difficulty was eliminated, other serious problems 

 presented themselves. As yet no single individual has been followed 

 through all stages of its life cycle. The immature forms cannot be 

 kept under observation when piled upon each other in large colonies. 

 When small colonies are started, the cannibalistic instinct of the ants 

 becomes more noticeable and before a series of eggs will hatch, or a 

 group of larvse become full grown, they may be eaten by their supposed 

 caretakers. 



Life-History 



Egg. — The eggs (PL 2, fig. 1) are pearly white with a bright luster 

 which changes, just before hatching, to a clear, semi translucent color. 

 They are elliptical in shape and about ,25 mm. long. The eggs are 

 covered with a viscid substance which enables them to adhere in 

 packets for purposes of transportation by workers or to the surfaces 

 where deposited. 



Eggs are laid by the fertilized queens and cared for by the workers. 

 Queens, when unattended by workers, will care for and carry packets 

 of eggs from place to place in the nests. Unless eggs are attended by 

 either workers or a queen, they will not hatch. 



Fertilized queens collected in the field and placed in artificial nests 

 cease egg laying almost entirely, and the few that are occasionally laid 

 are soon greedily eaten by the workers. This condition, coupled with 

 the fact that large numbers of eggs in a nest are hard to keep under 

 observation, makes it difficult to determine the length of the incuba- 

 tion period. The methods used by Newell and Barber (24) on the 

 Argentine ant were employed to work out the length of the egg stage. 

 A fertile queen was placed in a nest with a small number of workers 

 and assuming the time from the laying of the first egg to the time of 

 the first one hatching to be the time required for incubation. This 

 period was found to vary from 16 to 28 days, depending on tempera- 

 ture and moisture conditions. The daily egg-laying record of eight 

 queens was taken for a period of 16 days by removing from the nest 

 eggs laid during each day. The average number of eggs laid was 103.3. 

 The greatest number from one individual was 387 and the smallest 

 was 27. One queen deposited 105 eggs in a single day. Table I 

 shows how the egg record of a queen will decrease after being put in 

 an artificial nest. This queen was taken in a large colony May 10. 



