40 



however, there are no indications of disease other than 

 premature death (Brooks, 1974). Individual fire ant workers 

 infected with Thelohania solenopsae (Knell et al. , 1977) 

 or any of four undescribed species of microsporidia, for 

 example, cannot be differentiated from healthy specimens 

 by either appearance or behavior. Diagnosis of these infec- 

 tions must be made by microscopic examination or, in the 

 case of T. solenopsae , by observing cysts in dissected gas- 

 ters. Similarly, bees, Apis spp. , infected by Nosema apis 

 Zander are completely devoid of outward signs of disease, 

 and even histological diagnosis is difficult (Bailey, 1981). 



Pupae of S^. geminata infected by B. dimorpha exhibit 

 pathognomonic signs that are obvious, and, to the best of 

 my knowledge, unique. Jouvenaz and Hazard (1978) attributed 

 these manifestations to destruction of the hypodermis and 

 described them as follows: 



A clear area in the occipital region of the head, 

 which appears about the time the developing eyes 

 become prominent, is usually the first noticeable 

 change. Later, similar clear areas appear in 

 the petiole and gaster, and the eyes become irreg- 

 ular in outline and appear sunken. Pupae having 

 such changes do not mature or even melanize. In- 

 stead, the clear areas increase in size, and the 

 cuticle eventually ruptures. (p. 27) 



Jouvenaz and Hazard also noted that NMB spores develop in the 



hypodermis, and MB spores develop in the fat body. 



This brief description of the appearance of diseased 



worker pupae and notation of tissue specificity of the spore 



types is all that has been published on the pathology of 



