NATURAL PARASITES OF FLEAS 435 



per cent of the dog fleas (Ctenocephalus canis) caught in November 

 and December in Berlin infected with Herpetomonas ctenocephali, 

 Fantham, this species having been previously noted by Fantham in 

 England and Marzocchi in Turin. Three per cent of Ctenocephalus 

 fells are infected with a similar parasite in Madras. Herpetomonas 

 ctenopthalmi, Mackinnon, is found in Ctenopthalmus agyrtes, the 

 common flea of field mice in England; Herpetomonas pattoni, Swingle, 

 is recorded from P. brasiliensis * and P. sp., from Ceratophyllus lucifer, 

 Rothsch., and from Ceratophyllus fasciatus in France ; Ceratophyllus 

 alladinis, from the Indian squirrel, Funambulus palmar um, also 

 harbours a Herpetomonas. Xenopsylla cleopatrae, which occurs on 

 the jerboa in Egypt, is infected with a flagellate (Herpetomonas?). 

 In C. agyrtes, in addition to the Herpetomonas, there is also a 

 Crithidia, described by Patton and Strickland ; Hystrichopsylla talpae, 

 the mole flea, harbours Crithidia hystrichopsyllae, Mackinnon. Most 

 important of all, Pulex irritans has been shown by Porter, working 

 in England, to be naturally infected with Crithidia pulicis. The 

 importance of the flagellates from fleas which are found on the dog 

 and on man cannot be over-estimated, for they are, at one stage 

 of their life history, practically indistinguishable from the parasite of 

 Kala Azar. The early stages of the species occurring in Ctenocephalus 

 felts and Ceratophyllus alladinis are passed in the Malpighian tubes 

 of the larva, and are almost motionless ; as the larva pupates the 

 parasites mature and pass down to the hind-gut, where they may be 

 found in the adult, forming a palisade around the wall. They are 

 passed out in large numbers with the faeces of the flea. Probably 

 all these flagellates reach the adult through the larva, and return to 

 the larva when it absorbs the blood-containing faeces of the adult. 



Gregarines are frequently found in the intestinal tract of adult and 

 larval fleas. One is recorded by Ross in Ctenocephalus ' serraticeps ', 

 from dogs in Egypt, and another by Strickland from Ceratophyllus 

 fasciatus. Ashworth and Rettie have recently described a new species, 

 Stenina rotundata, from several species of the genus Ceratophyllus ; 

 it was found most frequently in Ceratophyllus styx from the nest of the 

 sand marten, 



Malpighella refringens, Minchin, occurs in the rat flea, Ceratophyllus 

 fasciatus, and was also found by N oiler in the dog flea. The dog 

 flea also harbours a species of Nosema (Noller). A spirochaete has been 

 found in the larva of Ctenocephalus felis (Patton). 



* cheopis 



