HeRPETOMONAS ASrONOOl'I 

 liY 



W. M. AuEKs, Ph.D. 



The 



alimentary 

 tract of the 

 " Melon bug" 



Siom 



During the winter of 1908, when working in the Wellcome Tropical Research 

 Laboratories at Khartoum, Dr. Balfour proposed that I should examine a number of 

 parasites both of plants and animals in order to ascertain if the former were infested 

 with any other species of parasite ; in other words, to study what has been termed 

 hyper-parasitism. 



The first parasite examined was the " Melon Bug," Aspongopus viduatus, a large 

 hemipterous insect which causes considerable damage to the melon crops in Khartoum. 

 The adult female lays her eggs on the leaves of the melon plant. The eggs are green 

 in colour and usually number from 12 to 15. The young larvae in the winter months 

 hatch out in about 12 days ; they are bright crimson in colour, shed tlieir skins several 

 times, and develop into nymphs. The nymphs vary much in colour, some being of a 



bright red, whilst others are blackish. The bugs, if supx^lied 

 regularly with fresh food, will live well in captivity. 



The alimentary tract (w/de Fig. 36) of the adult Aspongopus 

 consists of a short narrow (Esophagus which opens into a large 

 sacculated crop : this adjoins the large round stomach, directly 

 behind which is another dilatation, the mid-glit : this is some- 

 what pear-shaped, and brightly coloured, and it is continuous 

 with the small intestine, which is generally much coiled. At 

 the junction of the small intestine and the colon, four long 

 narrow Malpighian tubes arise, and the colon terminates 

 directly in the rectum. The salivary glands are easily 

 recognised as a pair of white glistening bodies, each consisting 

 of five acini which open into the narrow oesophagus. In adult 

 females the ovaries, which are large green grape-like bodies 

 situated on either side of the body cavity, are very conspicuous. 

 The wliole of the abdominal organs are in close relation to 

 the fat bodies and tracheal tubes. Seven out of 120 adults 

 were found to be infected ; many nymphs were examined but 

 always with negative results. 



The intestinal tract was removed and placed in a watch glass containing normal 

 saline solution, a small piece of the crop was out away and the contents placed on a 

 slide and examined. In many cases swarms of herpetomonads were seen actively 

 swimming about. Other pieces of the crop were now taken and their contents smeared 

 out for staining. The films thus obtained were fixed in osmic acid vapour for a few- 

 seconds and then placed for ten minutes in absolute alcohol. I found Leishman's stain 

 the best to use, as with Giemsa's it was very difficult to stain the flagella satisfactorily. 



in^iou Lniy, Aspongopus vhiutitus 



Methods 



Structuee and Life-Cycle of the Paeasite 



I shall commence by describing what I regard as the resting stage of the parasite. 

 Bodies probably representing this stage were often found in the crop and on two 



