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potentially infected flies were performed according to the technique 

 of Johnson et aj_. (1963). Since the initial aim was to demonstrate 

 transmission of parasites, most dissections occurred post mortem , or 

 when the fly was obviously too weak to refeed. Data recorded for each 

 specimen included eclosion date, feeding information (to include size 

 of blood meal and host), oviposition date and number of eggs 

 deposited, longevity, and pararasite information. 



To establish the complete life cycle of L mexicana in Lu . 

 diabol ica , "healthy" infected flies were immobilized by refrigeration 

 for ten minutes at 0°C, and dissected at 12, 18, and 24 hrs, to 

 determine when promastigotes first appeared, then at 24-hr intervals 

 for the next seven days. Ten flies were dissected at each time 

 interval. A brief description of the infection, location, morphology 

 and behavior of the parasites was recorded for each dissection. 

 Phase-contrast photomicrographs of live and Giemsa-stained parasites 

 and measurements of the various forms were taken through a Zeiss Photo 

 III microscope. 



Ultrastructure Studies 



The purpose of these studies was to examine the ultrastructure of 

 amastigotes in hamsters infected by bite of Ljj. diabol ica , and 

 promastigotes present in the gut of infected flies. To obtain the 

 amastigotes in macrophage cells, aspirates were drawn from 

 histiocytomas of infected hamsters and centrifuged at 1,000 gravities 

 for one minute to concentrate the cells into a small pellet. To 

 maintain the integrity of the cell pellets during fixation and 

 embedding, they were first fixed in 1% osmium tetroxide for 1 hr, then 



