BULLETIN OF THE BUSSEY INSTITUTION. 113 
middle thing between an Aphis and a Coccus, having the shape of the 
latter, but not its carapace, the body remaining soft and becoming 
clothed with a woolly covering. This animal, together with one or 
several species of true Coccus, are always found with the Fumago, 
sometimes in such numbers that there is not a leaf which does not 
harbor a cluster of them in its axil, where they attack and ruin the 
young leaf or flower-bud by their punctures. Of course, they are 
found on the leaves too, principally the lower face, where by their 
punctures they produce that exudation of gummy substance which 
covers the leaf often in large patches. Whether the exudation pro- 
ceeds direct from the leaf or from the body of the animal, I cannot 
say; but it is always after its appearance that the first black specks of 
the Fumago begin to show themselves. The Fumago, of itself, does 
little harm, at least in leaves with a glossy surface and destitute of such 
retaining apparatus as there is in the olive; it, of course, impedes the 
respiration for the time being, but a good rainy season washes it well 
off and leaves the tree clean.” 
During the month of October, 1876, we had a good opportunity to 
observe how closely the fungus known as Capnodium elongatum fol- 
lowed the presence of certain insects. This fungus, which is botanically 
closely related to the fungus which attacks the olives and oranges of 
California, was abundant at Auburndale, Mass. We observed a 
bluish gray mass which, in the distance, seemed like the plasmodium 
of some species of Myxomycetes, judging from the color and the 
manner in which it was spread over every thing with which it came in 
contact, entirely regardless of its nature, whether vegetable or mineral. 
_ A closer examination showed that the alder-bushes on or near which 
the fungus was growing were covered with insects of a white color, 
covered with a woolly substance and producing a copious oily exuda- 
tion. Mr. Edward Burgess, to whom specimens of the insects were 
sent, kindly informs us that they belong to the genus Hriosoma. 
Wherever the exudation fell, whether on other insects, on the ground, 
on dead sticks, ferns, or any other substance, the fungus at once made 
its appearance. In some cases, where the exudation dropped upon 
other insects, they were covered by the bluish-black fungus, while still 
alive. All this serves to strengthen the view, previously maintained, 
that the fungi of this group grow upon the exudation of insects rather 
than directly upon the bark and leaves of plants. 
VOL. ll. 8 
