PROSPECTS FOR 1887. 65 
rain into the sewer traps. Now, however vigilant the authorities may 
be during the heat of summer in cleaning out these traps, at the ap- 
proach of cold weather the necessity for their frequent cleaning is sup- 
posed to be removed. Asa consequence of this, vast masses of black, 
decomposing, and reeking leaves are left to fester during the late fall 
and early winter, and even through the whole winter, sending forth their 
injurious and insidious emanations from every street corner. From 
personal experience we. are convinced that this is a source of much sick- 
ness hitherto almost entirely overlooked, and it behooves the authori- 
ties to have the traps on all the tree-planted streets thoroughly cleaned 
out immediately after the trees have become essentially bare. 
PROSPECTS THE COMING SEASON.—CONCLUSION. 
From the habits of the Orgyia as compared with the Web-worm there 
is good reason to believe that the former will become in the future more 
and more numerous and more and more of a nuisance, just as it has be- 
come the most grievous pest in Boston and Philadelphia and other cities 
where the trees are older. As to the prospects of a repetition of the 
Web-worm nuisance the coming season, the probabilities are that it will 
be very much less troublesome than it was in 1886. It is almost a uni- 
versal rule in insect life that abnormal increase of a plant-feeding species 
is followed by a sudden check. This is due to two causes: First, the 
great multiplication of the parasites and natural enemies of the species 
which such undue increase permits; secondly, to the greater feebleness 
and tendency to disease resulting from insufficient food, which is a very 
general accompaniment of such undue increase. From the diseased 
condition in which the bulk of the last generation of the Web-worm 
was found, and from the great increase in its parasites that we know to 
have taken place from actual observation, we may safely expect ex- 
ceptional immunity the present year. 
SOURCE OF ILLUSTRATIONS. 
Plates I and II are from photographs. Figures 1,2,3,4,5,6,and 11 are republished 
from former Government reports by the author. Figures 7, 12,13, 14, 15, 20, 21, 22, and 
26 are from the author’s Reports on the Insects of Missouri. Figures 9, 10, and 25 are 
from other miscellaneous papers by the author, Figure 8 is from Hubbard, and fig- 
ure 16 is from Glover; while figures 17, 18,19, 23,24, and 27 were drawn for this Bul. 
letin and for our Annual Report as Entomologist to the Department of Agriculture 
for 1886. 
Mp2i—Bbull, 10-——5 
