ACTING STATE ENTOMOLOGIST. 
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days, tliey become completely enveloped in a white cottony mass, the filaments of 
which are five or six times as long as the insects themselves, and, though somewhat 
crinkled and irregular, radiate in general from the body of the insect as from a centre. 
Attached to this mass may almost always be seen one or two globules of sap, such as 
we often meet w r itli rolling about among the powdery matter secreted by the Plant-lice 
that inhabit “ Galls.” Dr. Fitch figures and describes the cottony matter as protruding 
only from the tip of the abdomen of the larva ; (N. Y. Hep. I. p. 9); but in reality it 
proceeds in an infinity of very fine filaments from the general upper surface of the 
insect, though perhaps, as stated by Mr. Riley, it is secreted rather more densely on the 
hinder portion of the back. Most certainly it is not secreted exclusively either from 
the mouth or from the tail; for I have had hundreds of these lice sucking away at apple- 
roots in a glass vase for a month, and have thus been enabled carefully to study the 
mode in which the cottony matter is produced. So far as regards the winged insect, 
Dr. Fitch expressly says that “ the head and the abdomen on its back are covered with 
a dense mass of flocculent down (ibid. ;) and Dr. Harris, speaking of the larva of the 
true Woolly Plant-louse, says that the cottony down “ seems to issue from all the pores 
of the skin of the abdomen.” ( Inj. Ins. p. 243.) 
Dr. A. S. Packard, junr., of Maine, has published some very amusing and sprightly 
banter, in ridicule of my theory, that the cocoon of all Gall-gnats ( Cecidomyia ) is exuded 
from the general surface of their bodies , not, as in the case of Caterpillars &c., spun from 
the mouth , which this author maintains to be the true theory in the case of Gall-gnats. 
If he had given himself the trouble to read the paragraphs w'hich he undertakes to 
criticise, he would have seen that, in the case of two distinct species of Gall-gnats, the 
fact of the cocoon being exuded and not spun has been proved by actual observation by 
Winnertz and by Osten Sacken.* And as to his disbelief in the possibility of any cocoon 
being exuded from the general surface of the body, if he had ever examined with his 
own eyes any of these Woolly root-feeding Plant-lice, he would have seen at once that 
the woolly matter is not secreted from the mouth, nor even from the tail, but from the 
general surface of the body. Many other larvae do the same thing. On May 25th I 
found in a nest of Yellow Ants (Formica aphidicola , Walsh,) situated in the decayed 
stump of a Honey-locust, several remarkable woolly larvae, which a month afterwards 
produced a species of Ladybird (Hyperaspis punctata , Melsh.) These larvae were covered 
on the back with dense white cottony down, precisely like that of root-lice ; on remov¬ 
ing some of which lightly with a moist camel’s hair pencil, little globules of a yellowish 
fluid started out from the skin of the larva, evidently from the same pores from which 
the cottony down had previously exuded. This is the only genus of Ladybirds (Coccin- 
ella family) known to me, the larvae of which exude matter of this precise description 
from their bodies ; but it was long ago discovered that in another genus (Scymnus) the 
larvae have their bodies garnished with whitish cottony tufts; and on examination it 
will be found that these tufts also are mere secretions from the pores of the body, and 
not organized appendages like the hairs of a caterpillar or the scales on the wings of a 
butterfly. The bluish white powdery matter, which is well known to form gradually 
on the outside of the bodies of certain male Dragon-flies (Libellula and Agrion families) 
as they approach maturity, and also on those of several other insects belonging to 
other Families and Orders, for instance the so-called Locusts (Cicada family,) must 
^Compare my Paper Proc. Ent. Soc. Phil. III. pp._560, 562 and Dr. Packard’s Paper ibid. VI. pp. 214 
— 5. 
