300 Mr. Ernest Ewart Unwin on the 
of the Drosophila in Jamaica carrying large quantities of 
acetic organisms to cocoa beans fermenting in boxes, and 
also there is good reason to suppose that they are 
responsible for conveying cells of true Saccharomyces, 
and thus assist in regulating the fermentation of the 
beans.” 
Drosophila and Disease-—Drosophila flies may also be 
one of the means of spreading typhoid fever. They have 
been known to breed in human excrement and also to 
feed upon it. If this excrement contains typhoid bacilli, 
infection may be carried into houses. “As this fly 
(Drosophila ampelophila) is frequently found in houses in 
the?autumn about dishes containing fruit, and as it also 
affects canned fruits, pickles, raspberry vinegar and similar 
substances, this discovery that it will and does breed in 
human excrement makes this species and the following 
(D. funebris and D. busckii) very dangerous ones.” * 
Mr. T. H. Taylor has drawn my attention to some larvee 
living in the decaying crowns of swedes, and also mining 
the leaf-stalks. Upon examination I found that these 
larvee closely resembled those of Drosophila funebris, 
although they were smaller in size. Having procured a 
supply of diseased swede-crowns, I kept the larve alive 
until they pupated, and then obtained the flies, which 
proved to belong to a small brownish species, Drosophila 
JSenestrarum, Fall. 
Structure of the Larva of D. fenestrarum—In general 
structure this larva agrees with the /wnebris larva, but 
there are one or two interesting points of difference, which 
are connected with its habit of mining the leaf-stalks of 
swedes, instead of living in decaying fruit like D. funebris, 
The minute hooks, which in PD. funebris are arranged 
in eleven narrow bands, here almost completely cover the 
body. The anal pseudopods are conspicuous, and are 
covered with minute hooks. I have watched live larvee in 
their burrows, and the use of these anal pseudopods in 
giving a powerful purchase to the body was very evident. 
As would be expected from the circumstance that the larva 
of fenestrarum is not buried in its food, we do not find the 
posterior spiracles carried upon an extensible process, as in 
D. funebris, but protruding only a short way beyond the 
end of the body. The anterior spiracles exhibit the same 
digitate structure as in D. funebris; at pupation they are 
* Howard (1900). 
