114 Uiiiveraifij of Calif ontia PuhUcations in Zoologt/ | Vol. 10 



occupants at night. Tlie bites are annoying, cause local inflammation, 

 and general malaise, but no permanent ill effects so far as is known. 

 Among the various insects, principally Coleoptera, which have been 

 sent in to us as the supposed disturbers were a few individuals of 

 Triatoma protracta Uhler. 



"We are indebted to Mr. E. P. Van Duzee for its identification, and 

 also to him and to Mr. W. S. Wright for a supply of bugs which have 

 been secured from the nests of the wood rat, Neotonia fuscipes. 



It is the purpose of this present preliminary paper to place on 

 record the discovery, in the digestive tract of this bug from the nest 

 of the wood rat, of a trypanosome in various stages of development, 

 which, since it is associated in the stomach of the bug with the rem- 

 nants of mammalian blood corpuscles, is presumably a parasite of 

 the blood of the wood rat. We hope to be able to elaborate its life- 

 history more fully in a future paper. 



The most completely known life-history of a trypanosome is that 

 of Trypanosoma Icwisi of the rat, which has the flea for its inverte- 

 brate host. We owe to Minchin and Thomson (1915) our fullest 

 account of the stages in the invertebrate host. Since the evidence 

 at hand indicates that the form we have found in Triatoma is in some 

 important particulars much like those which these investigators found 

 in the flea, rather than like the stages described by Chagas (1909) in 

 Conorlnnus for Schizotrypanum cruzi, we shall follow the terminology 

 of the former authors rather than that of the Brazilian investigator, 

 with the important exception that we will call the kinetonucleus the 

 parabasal body (see Kofoid, 1916). Our paper should therefore be 

 compared with that of Minchin and Thomson and especially with 

 their diagrammatic presentation of the life-cycle in the flea, as shown 

 in their plate 45. 



In brief, the cycle which they have found is as follows: The 

 trypanosome ingested by the flea with the blood of the rat passes 

 through a stomach, and a later rectal phase. In the former it retains 

 its trypanosome characters. In the early stomach phase the nucleus 

 and parabasal are far apart, the latter being well towards the posterior 

 end of the body. It then enters an epithelial cell of the stomach wall, 

 undergoes multiple fission therein, and emerges as a smaller, more 

 slender merozoite with the parabasal somewhat nearer the nucleus. 

 These merozoites may repeat the process of intracellular multiple 

 fission in the stomach, or may pass into the rectum, where they trans- 

 form at once into the crithidial phase marked by the migration of 



