422 SANITARY ENTOMOLOGY 



Haemogregarina (Haemogregarina) mauritanica (Sergent and Ser- 

 gent), a parasite of Testudo mauritanica, is transmitted by Hyalomma 

 aegyptium (Linnaeus) Koch, according to Von Prowazek. 



Haemogregarina (Hepatozoon) jaculi (Balfour), parasite of the 

 jerboas (Jacidus gordoni and J. orientalis), while usually carried by 

 the flea, may be carried by the mite, Dermanyssus gallinae Redi, according 

 to Von Prowazek. 



Haemogregarina (Hepatozoon) leporis (Patton), a parasite of the 

 rabbit Lepus nigricollis, may be mechanically carried by Haemaphysalis 

 flava Neumann in India, according to Von Prowazek. 



Haemogregarina (Hepatozoon) muris (Balfour) the cause of RAT 

 ANEMIA, was found by Miller to pass its schizogony in the rat and its 

 sporogony in the rat mite Laelaps echidninus Berlese. In sucking the 

 blood of the rat the mite takes up the leucocytes containing the gameto- 

 cytes of this organism, which are then liberated from their cells by the 

 digestive action of the mite's gut. They arrange themselves in couples 

 which are at first quite similar, but which later differentiate into macro- 

 gametes and microgametes. Zygosis now takes place forming an ookinete 

 which grows, and, leaving the gut by piercing the wall, forces its waj' 

 into the body cavity and further into the sheaths of the muscles and 

 into the investing membrane of the salivary glands. In the tissues it 

 encysts and becomes the oocyst which grows rapidly in size and under- 

 goes nuclear division. The daughter nuclei migrate to the periphery 

 which becomes covered with 50 to 100 bud-like projections, in each of 

 which a nucleus is to be found. These buds break off' from the central 

 mass and form sporoblasts, the nuclei of which divide to foi'm daughter 

 nuclei which gather at the poles, while the whole sporoblast encysts. 

 Short rod-like processes of cytoplasm, each containing a nucleus, now 

 break off from the sporoblast and become sporozoites, of which there 

 are on an average 16 to each sporoblast. 



Infection of the rat takes place by ingestion of the mites, when the 

 sporozoites are liberated by the juices of the duodenum and become 

 actively motile, striated vermicules which penetrate the intestinal villi, 

 enter the blood system, and are carried to the liver, into the cells of 

 which they penetrate and start the cycle of schizogony. As the mites 

 leave the rats during the daytime, only feeding on them during the night, 

 it is easy to understand the manner in which the disease spreads from 

 the sick to the healthy. 



Hcemogregarina (Karyolysus) lacertarum (Danilewsky), a parasite 

 of lizards of the genus Lacerta, is recorded by Chatton and Roubaud from 

 nymphs of mites of the family Dermanyssid^, in which the cycle of sporog- 

 ony takes place. 



