No.413.] REVIEWS OF RECENT LITERATURE. 407 
houses. By comparing the two series, those visiting and bred from 
excrement and those found in houses, it is at once apparent what 
species are liable to carry disease germs. The results show that 
practically all of the house flies occasionally breed in or visit human 
excrement. It is thus possible that almost any house fly may carry 
the germs of typhoid fever. The next step in this process, vzz., to 
find out by experiment whether flies actually carry germs on their 
tarsi and labella, was not investigated. 
No less than thirty-six species of flies were reared from excrement, 
and forty-one other species captured visiting the same material. 
Among those bred were the common house fly (Musca domestica), 
and the pomace fly (Drosophila ampelophila). The latter is an 
especially dangerous species, as it not only frequents houses, but 
also occurs on grapes and other fruits exposed on the market. 
In the course of the work, many new and interesting observations 
of purely scientific value were made on the life history of various 
species. A large amount of the disagreeable work was performed 
by Mr. F. C. Pratt, and the determination of the flies rests on the 
authority of Mr. D. W. Coquillett. N. B. 
Trematode Fauna of Egypt.t— Just as the earlier works of 
Looss marked a new epoch in the study of the comparative anatomy 
of the distomes, so the present paper is destined to be the starting 
point of a movement toward the rational dismemberment of an 
ancient and honorable genus — Distomum. Not that others have 
failed to recognize its heterogeneous character, or to attempt its 
dissolution, but that up to the appearance of the paper under dis- 
cussion no one has indicated a reasonable way to the end desired. 
Many authors have recognized groups of forms whose relationship 
was evident, and yet have failed to give such groups their true posi- 
tion as genera, or have seized upon single and insufficient characters 
to delimit them. Thus Rudolphi endeavored to employ external 
features, which in a group of such uniform exterior does not 
Suffice ; Dujardin selected a single feature, the character of the ali- 
mentary canal, for the major part of his genera, while both Diesing 
and Monticelli erred in the same direction. To be sure, certain 
small groups were recognized and set off from the remainder, but 
the systems proposed have never met general acceptance, probably 
'Looss, A. Weitere Beitráge zur Kenntniss der Trematoden-Fauna Aegyp- 
es, zugleich ein Versuch einer natiirlichen Gliederung des Genus Distomum 
Retzius, Zool. Jahrb., Abt. Syst., Bd. xii, pp. 521-784, 9 pls. 
