STRUGTUKE AND LIFE-HISTOEY OF CRITHIDIA MELOPHAGIA. 213 



division occurs in both the pre-flagellate and the flagellate 

 stages of the pai*asite. 



(10) Infection of Melophagus ovinus with C. melo- 

 phagia is either hereditai-y or casual. In the case of casual 

 infection the insects ingest the post-flagellates voided with 

 the feeces of other Melophagus. 



(11) A very dilute solution of grape-sugar causes the 

 parasites to divide. There are only traces of sugar in both 

 sheep-serum and wool extract. ' 



(12) Sheep's blood or human blood added to the Crithidia 

 also increased the rapidity of their growth and division. 



(13) A fungus present in the Malpighian tubules and gut 

 of the ked (see Appendix II) has a rapid, fatal effect on the 

 Crithidia. 



(14-) An anti-coagulin is present in the salivary glands, 

 stomach and intestine of Melophagus ovinus (see Appen- 

 dix III). 



(15) A new spirochsete, S. melophagi, was found in 

 the gut, ovaries and puparia of a few of the Melophagus 

 examined (see Appendix I). 



Appendix I. 



On the Occurrence of a Spiroclia3te, S. melophagi, 

 n. sp., in Melophagus ovinus. 



I wish to record the occurrence of a rare spirochsete in the 

 gut, ovaries and puparia of Melophagus ovinus. The 

 spirochgete was observed in life in the above-mentioned 

 organs of a very few of the Melophagus examined, and at 

 very different periods of the year (February, September, 

 October). Very few spirochastes occurred, and consequently it 

 is impossible to give full details regarding size and structure. 

 The organisms seen were from 10 fx to 30 fx long and were 

 narrow. They vary in length, some being practically half 

 the length of others, indicating the probability of transverse 

 division. As some parasites were thicker than others there 



