22 



spore types in the first 200 spores seen. Twenty-five infected 

 pupae from a laboratory colony that had been infected with a 

 crude suspension of mixed spores for routine propagation 

 of the parasite were also examined. 



Results 



Solenopsis geminata adults did not ingest spores into 

 the crop; instead, they diverted them to the infrabuccal 

 cavity (Figs 3 and 4). One hour after exposure to food 

 containing spores, 100 of the 160 workers that were examined 

 contained spores in their infrabuccal cavities. Not one 

 contained even a single spore in the digestive tract. All 

 eight infrabuccal pellets removed from f ourth-instar larvae 

 shortly after deposition by workers contained numerous spores. 



Only f ourth-instar larvae became infected with B. dimorpha . 

 Seventy-one of the 109 that were exposed as f ourth-instar 

 larvae became infected; none of the 7 9 immatures that were 

 exposed to spores as pref ourth-instar larvae became infected. 



Nonmembrane bound spores were infective perorally for 

 S^. geminata and produced infections with pathognomonic 

 signs and both spore types. Furthermore, the spore types 

 were produced in normal ratios. Pupae that had been fed 

 NMB spores only contained 28.6% ± 10.2 (range 16-48%) MB 

 spores; those that had been fed both spore types contained 

 30.8% ±7.8 (range 16-43%) MB spores. 



In the meconia of larvae fed the suspension of mature 

 spores of both types, 1,723 (97.1%) of the 1,774 spores found 



