204 



HEBPETOMONAS ASPONUOl'I 



Process of 

 division 



unstained area is present around the blepharoplast. The nucleus is generally spherical 

 in shape and is placed centrally, but occasionally it is situated behind. The nucleus 

 shows great affinity for the red constituent of the Eomanowsky stain, but in more or 

 less decolorised preparations chromosomes can be distinctly made out. The blepharoplast 

 is more rod-shaped than round : it stains very darkly and is situated at the anterior 

 portion of the flagellate. In many parasites it has a double appearance suggesting 

 commencing division. The flagellum measures about 13 /j in length ; it consists of one 

 stout filament which arises from an achromatic space somewhat anterior to the blepharo- 

 plast and passes out at the anterior end. The intra-cellular portion of the flagellum does 

 not differ from the rest, and no basal granule could be detected. On examining a flagellate 

 which is about to commence dividing (Fig- 37, q), it can be seen that the nucleus is 

 somewhat enlarged ; it does not stain so readily, and in some eases chromosomes are 

 recognisable. The blepharoplast is thickened and somewhat elongated. It was not 

 possible to ascertain if the second flagellum grew out of the micronucleus, or if it was 

 formed by the splitting of the original flagellum. After close examination of many 

 specimens it seems most probable that the new flagellum grows from the micronucleus 

 (Fig. 37, q) ; at a later stage the blepharoplast splits transversely (Fig. 37, r) and the two 

 halves become separated. The nucleus now becomes elongated and it undergoes division 

 (Fig. 37, (• and .«). A line is seen which commences at the root of the blepharoplast and 

 runs to the posterior end of the parasite. Along this line the parasite divides (Fig. 37, t), 

 the anterior end of the parasite separating first, the cleavage later extending to the 

 posterior end (Fig. 37, «). It is quite common to see all stages of division in the crop 

 in good infections. The parasites evidently divide many times, as division was observable 

 in quite small forms, and also in many larger forms which evidently gave rise to the 

 long thin form (Fig. 37, o and p) ; some of these long forms measured as much as 32 ^i. 

 Dividing parasites were always found in the crop, less often in the stomach and 

 mid-gut and very rarely in the rectum. As mentioned before, the bodies supposed to 

 Salivary glands be the resting stages were found in the faeces on two occasions. In one melon bug the 

 salivary glands were found to be swarming with parasites, many of which were dividing. 

 Several of the drawings were made from parasites from these glands. 



The method of infection 



Very little can be said on this point as infected bugs were extremely rare. Patton's 

 view that the liquid faeces are sucked up by other bugs seems by far the most acceptable 

 hypothesis regarding the mode of infection. As mentioned before, a large nmuber of 

 larvte and nymphs was examined but they were never found to be infected. In the few 

 infected bugs which were studied, careful examination of the ovaries was made but no 

 parasites were discovered. 



Experiiiienf.i 



An emulsion of the contents of the crop of a bug, which contained njany flagellates, 

 was made in salt solution and injected into a gerbil ; the result was negative, no infection 

 taking place. An attempt was made to keep the flagellates in citrate of soda solution, 

 but they all died quickly. 



Concluding Remarks 



Herpetoiiionas asponc/opi is a true parasite of Aspongopua viduatui!, the complete cycle 

 of development taking place in the alimentary tract of the bug. The parasite is not 

 transmitted hereditarily, but it probably is conveyed from host to host by the ingestion 



infected 



