OF WASHINGTON, VOLUME XIV, 1912. 77 



SOME NOTES ON THE TICK ORNITHODOROS TALAJE 



GUERIN. 



BY ALLAN H. JENNINGS. 



In 1910, while connected with the laboratory of Ancon 

 Hospital at Ancon, Panama Canal Zone, I made a series of 

 observations upon the domestic rats of Panama and their 

 ectoparasites, these observations being continued daily for 

 seven months. 



During that time about 2,300 rats were examined. The 

 material was received alive, chiefly from the health officer of 

 the city of Panama, though a small number of animals was 

 sent from Colon, together with a few from the Canal Zone. 

 The species received were, in the order of their abundance, 

 A fits norvegicus (brown rat), Afits rattns (black rat), A fits 

 alexandrinus (roof rat), and Mus ninsciiliis (house mouse). 



When chloroformed and examined for parasites, many rats 

 were found to be infested by large numbers of the larval stage 

 of an argasid tick which was subsequently identified by Mr. 

 Nathan Banks as Oniithodoros talaje. 



Though taken from all three of the species of rats, the brown 

 rat was by far the most heavily infested and of the many 

 hundreds of the ticks examined but a small percentage was 

 taken upon the other forms, none occurring upon the house 

 mouse. It should be noted that the nesting habits of the 

 brown rat are different from those of the black and roof 

 species in that the brown rat is essentially a burrowing animal, 

 while the nests of the other species are usually above ground, 

 in the walls of houses and even in trees. 



Brown rats from Colon were also found to harbor the ticks, 

 though the proportion of animals infested and the degree of 

 infestation was less than among those from the city of Pan- 

 ama. However, the number received from the former city 

 was not great enough to warrant the formation of definite 

 conclusions as to their abundance. But that ( Iruithodoros. 

 talaje occurs on the Atlantic side of the Isthmus is certain 



The larvae were attache'! to almost all parts of the bodies 

 of the animals, but showed a marked preference for 1 In- 

 posterior portion of the dorsum. A peculiarity regarding 

 the points of attachment was that in almost all infested 

 animals, especially in those in which the infestation was heavy, 

 a considerable portion of the parasites could have IK-CD easily 

 reached by the teeth of the host, yet they \\ere not destroyed. 

 Thus it would seem that a cetrain toleration for them has been 

 established in the rodent. In many cases in which gross 

 infestation of the dorsum occurred, the irritation caused by 



