265 
and the feeling of emulation among scientific workers quite commend- 
able, yet in all of this activity it is well before one does the honors of 
introducing to his fellows a new-found depredator to look well to it that 
some one has not performed the saine office even before the time of either 
himself or his immediate ancestors. .The earlier agricultural and horti- 
cultural publications of the country are full of references to the depreda- 
tions of insects whose names, if they had any, were unknown to the 
observer, yet often the most important characteristics are so clearly | 
described as to leave little or no doubt as to the species involved. 
THE COLOR OF A HOST AND ITS RELATION TO PARASITISM. 
By C. W. STILES, Ph. D., and A. Hassati, M. R. C. V.8., Bureau of Animal Industry, 
U. S. Department of Agriculture. 
In Prof. Wallace’s book on Darwinism, it is stated that white cattle 
are more subject to the attack of flies than dark colored cattle, and 
that white fowls are more subject to the gape-worm disease than dark 
fowls. In regard to the former statement, two explanations immedi- 
ately occurred to us, 7. ¢., (1) the flies would be more easily seen upon 
a white background than upon a dark background, and the assumed 
correlation between the host and its parasites would be in this case 
only apparent, or (2) the white color might attract the flies more than 
a dark color. It is, in fact, a common household belief that if ob- 
jects of various colors are suspended from the ceiling of a room, the 
light-colored objects attract the flies more than the dark colored ob- 
jects. We can hardly see, though, how the white color of fowls can 
stand in any relation to their Nematode parasites, since the latter have 
no organs of sight, and the only explanation which we could imagine 
was that the white fowls are constitutionally weaker than dark fowls, 
and would on this account succumb more easily to the ravages of the 
worms than darker fowls with hardier constitutions. There is, how- 
ever, serious objection to assuming that white fowls are inferior to 
dark fowls, since white breeds of fowls exist which are very hardy—the 
White Leghorn, for instance. 
Upon inquiring among our friends we find the most contradictory 
opinions in regard to the two statements by Wallace mentioned above. 
Mr. Howard states that there is certainly no connection between the color 
of cattle and the Horn-fly (Haematobia serrata); several persons have 
noticed that white horses are attacked more by flies than dark horses, 
while other persons are not willing to admit this statement. From two 
sources we have the statement that on two farms it was very noticeable 
that the white chickens were considerably weaker than the dark fowls, 
while from other sources we have the opposite statement. 
In hopes of obtaining some decisive evidence for or against Professor 
