214 EKTOMOtoGiCAL NEWS. [May, 'i5 



Observations on the Preoviposition, Oviposition and 



Incubation Periods of Dermacentor nitens 



in Panama (Arach., Acar.).* 



By L. H. Dunn, Board of Health Laboratory, Ancon, 

 Canal Zone. 



In January, 1913, Dr. Darling^ detected in Panama a horse 

 infected with Piroplasma cahalli. This was the first record of 

 this piroplasma in the New World, and in view of its probable 

 transmission by the tropical horse tick, D. nitens, the follow- 

 ing observations were made concerning the bionomics of this 

 tick in Panama. 



According to Hooker,^ D. nitens passes both molts on the 

 host. Upon the hatching of the larval or seed ticks they attach 

 themselves to a suitable host, and, after engorging themselves 

 with blood, molt without becoming detached from the host. 

 After molting they appear in the nymphal stage and again be- 

 come engorged with blood and molt for the second time with- 

 out separation from the host. After the second molt the ticks 

 are in the adult stage and the females after copulation and 

 becoming engorged with blood drop to the ground to deposit 

 their eggs. This makes three blood meals taken from the same 

 host between the larval and adult stages. 



This species nearly always adopts horses and mules as hosts 

 — but are sometimes found on other animals — and the ears 

 seem to be the special place of attachment, although they may 

 frequently be found on other parts of the body — as on a horse's 

 neck under the mane — but in such cases they are generally 

 single individuals and not in colonies as they occur in the ears. 



A number of Dermacentor nitens was collected from a 

 small stray mule found wandering about in Guachapali Dis- 

 trict. Judging from its condition the mule had evidently been 

 straying about in the "Bush" for some time before coming 

 into Panama, as it was in very poor condition, having several 

 large festering sores on various parts of its body and was also 



♦ Read before The Medical Association of the Isthmian Canal Zone, 

 January 16, 1915. 



Uour. Inf. Dis. XIII, No. 2, Sep. 1913, Chicago. 

 *Jour. Econ. Entom., 1908, I, p. 47. 



