_ ENTOMOLOGICAL News. 353 
Sv eactemission of Bubonic Plague: a. Study of 
g the San Francisco Epidemic. 
“a By M. B. Mrrzaarn, B.S. 
he role of the flea in the trahsmission of bubonic plague 
$ particular interest to observations on the species of fleas 
-stin g rats in the San Francisco epidemic. 
In the present campaign of rodent extermination eighteen 
i rats have been examined by the writer. From the lat- 
a t of inant to December st he spent much of his time 
Miliitieinfected districts of San Francisco and other 
Re : where the existence of the plague was suspeeted. In 
___ this connection an effort was made to locate the source of the 
E ees id flea introduction into the infected regions. 
= om ms SEGCE AMD EteTRIBUTION OF SPECIES OF FLEAS, 
: _ From coasting ships and river steamers the common flea ob- 
is & d was of the species Ceratophyllus fasciatus Bosc, and 
those _ collected from ships from oriental ports were of the 
s Ctenopsylla musculi Duges and Pulex cheopis Roth. 
eae 5 ver eteeared to be a definite invasion of the introduced spe- 
de s. Along the water front and east to the Latin quarter in 
z. Be Bemis there came to my obseravtion certain evidence 
is | introduction. As far as could be determined the orien- 
Sal get flea seemed to disappear east of this line within ten city 
a and only the common rat flea, Ceratophyllus fasciatus, 
made its appearance. In outlying districts I have not succeeded 
collecting ship rat fleas. I have secured negative evidence 
} determine that the foreign fleas are alone responsible for 
Fhe transmission. On twenty plague rats not one of the 
alien species was obtained. The flea in evidence was that com- 
mon to the Pacific coast, Ceratophyllus fasciatus. This species 
is the predominant rat flea in the counties bordering the bay. 
It was collected in San Francisco, Oakland, Point Richmond, 
and in districts where plague had been reported by the local 
h boards. At Point Richmond nineteen rat fleas were col- 
tasted i in a warehouse which was a probable source of human 
Se ame 08 proved to be the common species. From one in- 
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