76 SANITARY ENTOMOLOGY 



ment necessary before they are ready to be returned to the definitive host, 

 after transformation of the nymphal tick to the adult stage. Noe be- 

 lieves that the dog becomes infected during the initial phase of attach- 

 ment of the adult. He also suggests that adult males which, unlike adult 

 females, may pass from one host to another are capable of acquiring 

 infection from one dog and transferring it to another. He has found 

 as many as 22 larvae of A. grassii in one male tick. Noe is of the 

 opinion that the larvae escape through thin portions of the cuticle of 

 the mouth parts of the tick and thus reach the final host in a way similar 

 to that followed by the larvae of D. immitis and other filarias trans- 

 mitted by mosquitoes. 



It is of interest to note that Grassi and Calandruccio (1890) found 

 larval nematodes in Rhipicephalus siculus (=i?. sanguineus) which they 

 identified as the larva of Filaria recondita {^Acanthocheilonema recon- 

 ditum). Noe thinks that these larvae may have been A. grassii rather 

 than A. reconditum. 



Evidently further investigations into the life history of A. grassii are 

 necessary before ticks can be accepted as the intermediate host of this 

 parasite. 



Acanthocheilonema reconditum (Grassi, 1890) Railliet, Henry and 



Langeron, 1912 



This nematode is a parasite of the dog and in the adult stage has been 

 collected from adipose tissue in the .neighborhood of the kidney. Accord- 

 ing to Grassi and Calandruccio (1890) the first-stage larvae occur in the 

 blood stream, and are the so-called Haematozoa of Lewis which have 

 been seen by many observers, first by Gruby and Delafond (1843), after- 

 wards by Lewis and others. Apparently, however, the larvae seen in 

 the blood of dogs by Grassi and Calandruccio as well as those known 

 as Lewis's Haematozoa are in reality the larvae of Dirofilaria repens. 

 Grassi and Calandruccio describe various stages of nematode larvae 

 found in fleas (Ctenocephalus canis, C. felis, and Pulex irritans) and in a 

 tick (Rhipicephalus siculus^R. sanguineus) as developmental stages in 

 the life history of A. reconditumi. According to Noe (1907, 1908), the 

 larvae found in R. sanguineus by Grassi and Calandruccio were probably 

 those of Acanthocheilonema grassii. 



Owing to the confusion existing with reference to the identity of the 

 parasite that Grassi and Calandruccio studied, the species to which the 

 larval nematodes observed in fleas belong, is uncertain. Grassi and Calan- 

 druccio's experiments can not be considered conclusive so far as con- 

 cerns the life history of A. reconditum. 



