Article beginning on page 321.
Psyche 5:321-324, 1888.

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PSYCHE.
*THE CORN DELPHACID, DELPHAX MAIDIS.
BY WILLIAM HARRIS ASHMEAD, JACKSONVILLE, FLA. As is well known, the rapid changes
taking place in the environments of a
new country, under the influence of
settlement and modern civilization, by
the destruction of the forests and the cul- tivation of the soil, induce corresponding changes in the natural environment of
insect life.
The natural food plants of hosts of in-
sects are destroyed, and these are com-
pelled, by the changed conditions, to
seek among the plants brought by civili- zation such food as will sustain existence and perpetuate their species. Under
these civilizing transformations, there- fore, new insect pests are continually
being brought to notice, appearing on
some well known crop previously en-
tirely exempt from their attacks, do
great injury, cause the planter anxiety, attract the attention of the entomologist, and require skill and prompt measures
for their destruction and the saving of a crop.
A new insect pest has lately appeared
on corn in Florida, to which I have
given the above name, that peculiarly
illustrates this point.
It belongs to the familyfulgoridae,
subfamily delphacinae, in the order hem- iptera, or suctorial bugs, and is apparently unknown to science, although found in
great numbers on growing corn in my
garden, and on coarse grass elsewhere.
Up to the present time, no species in
this family, at least to my knowledge,
has as yet been described or reported as living on or injuring this cereal in either the United States or Canada.
Many years ago, however, Prof. West-
wood, in the annals and magazine of
natural history, v. 6. p. 413, published in London, England, in I 841, illustrated and described a species, very closely re- lated to and resembling it somewhat, as
seriously destructive to sugar cane in the West Indies ; so that, after all, it is not so astonishing that a species in this fam- ily should now be found in the United
States on so closely allied a food plant. The "Corn Delphacid" was detected
early in July, 1888, my attention being
first called to it by the number of ants, Cremastoguster Zineola~is Say, which
were swarming on the leaves and crawl-
ing up and down the stalk. Ants never
congregate in numbers without cause ;
and, an examination as to their super-
abundance at this time soon revealed it- self in the discovery of this new corn




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pest ; for, as is the case when attracted to the aphides, occurring on other plants, they had gone there for the purpose of
lapping up the saccharine substance,
which, from the punctures of these pests, was exuding in considerable quantity,
as a sweet viscid fluid, frequently cover- ing most of the upper surface of the
blades, and particularly in notches
formed at the basis of the leaf-stalks,
where the larvae and maturing insects
were found to be fond of congregating.
INJURIES AND LIFE HISTORY.
The injurious affect, of this insect, on growing corn is readily apparent: the
depletion of its juices and the saccharine substance on which the young and old
feed, so necessary to growth and the
maturing of the crop, occurs from the
punctures of their beaks, whereby it is
stunted in growth and the ears never
fully mature ; moreover, it is still fur- ther injured, scarred and disfigured by
the ovipositor or egg-borer of the female, which is used as a saw or borer, to cut
into the cellular tissue of the blade or stalk, where she deposits her eggs.
The little cicatrices or scars, thus
made, and the depletion of the juices of the plant from the punctures of their
beaks, give to it a diseased, sickly appear- ance, that, in connection with the
swarming ants and flies, cannot fail to
attract attention.
No delphacid, that I am aware of,
has ever been tl~orougl~ly worked up
in all its stages, and the egg and newly hatched young have never been de-
scribed or figured ; and, as these are
peculiarly characteristic and probably
of biologic importance, it is particu-
larly gratifying to me, to have been so
situated to work up the life history of
the present species, and, to be able to
present illustrations of their many re-
markable peculiarities. ^
Finding the species so plentiful on
corn and grass in my own garden, for
some weeks, it was possible to make
visits daily, and thus, the opportunity
and satisfaction in working up and
studying the insect in all its stages -to a naturalist, the greatest of pleasures - was afforded me.
The egg, (fig. a), about I mm. in
length, is of a greatly elongated shape, narrowed into a more or less distinct
neck at base, and of a translucent white color, except a yellow yelk-like spot
near the base, shown in the figure as a
black dot.
The female makes an incision, with
the ovipositor, under the epidermis of a leaf or in the stalk, into the cellular
tissue, of a sufficient size to contain two eggs together, as is shown in the figure. After oviposition, the orifice is cemented with a greyish or white glutinous sub-
stance that appears externally, on the
surface of the leaf or stalk, only as a
cicatrice.
The eggs are laid in regular rows, a
slight distance apart, and invariably two are found together, never more or less.
Hundreds were examined but I always
found two together, as illustrated.
The egg hatches in from a week to
ten days, and a succession of broods




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March-Arpil 1890.1 -‰âÂ's2'-C 323
appear all during the last of July,
August and September, the young and
old, in various stages of growth, appear- ing together. Whether the broods
appear later than September I cannot at
present tell, as my observations on the
species were abruptly terminated by the
yellow-fever epidemic.
The newly hatched larva is shown in
figure 8. It is of a pale greenish white color and less than 2 mm. in length, and insect assuming more and more the
appearance of the imago ; the cephalic
prolongation disappears with the third
molt, when the frontal carinae are more
or less distinctly visible, as well as the three carinae on the thorax, and distinct wing pads appear.
There are two distinct forms of
imagos-a perfect winged and a brachyp-
terous form-which are briefly described
below, being, it is believed, together
in some of its characters quite dissimilar to the adult : The head has a remark-
able cephalic prolongation, shaped as
in the figure ; the thorax exhibits dorsally six quadrilateral plates ; the abdomen is composed of 7 segments, the basal one
being the longest ; the middle and an-
terior tarsi are only I-jointed, while the posterior tarsi are 2-jointed, the posterior tibiae being without the large movable
spur, so characteristic of the adult.
From this stage to the adult there are
five distinct molts, after each molt the with the figure, sufficient to distinguish the species.
Delphax maidis n. sp.
8 Length 2 mm. ; wing expanse 6$
mm. Pale greenish-yellow, in death
pale brownish yellow ; apex of 1st and
the apical half of 2nd antenna1 joints,
lower part of frons, spots on pleurae,
most of the abdomen, except the 1st
ventral segment and the lateral edges of the dorsal segments, smoky black.
Legs pale, the femora more or less em-
browned ; apex of posterior tibiae with




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324 ^<yl'c//&. [March-April 1890.
several black tipped spines and a large
movable spur ; tarsi 3-jointed, the basal joint longer than the other two to-
gether, all with black tipped spines or
teeth at apex ; the anterior and middle
tarsi shorter, the terminal joint the long- est, longer than the first two together. Face with three keels, the middle one
forked on the frons above; clypeus
also tricarinated, the middle carina deli- cate ; beak, apparently, but two-jointed, reaching far beyond the middle coxae,
the first joint being slightly the longer. Prothorax and mesothorax tricarinate,
those of the last being delicate or sub- obsolete. Front wings pale greenish-
brown, sub-hyaline, the apex of the
clavus and veins of apical cells more or less distinctly surrounded by fuliginous clouds, as shown in the figure (c).
Q . Length 2% n1m. ; wing expanse 7
mm. This sex agrees with the male,
except its slightly larger size, the cly- peus as well as the frons and all the
coxae are more or less distinctly em-
browned or blackish, while the apical
edges of the abdominal segments, as
well as the lateral edges and a broad
dorsal stripe, are yellow.
The ventral apical aspect of the two
sexes is shown in figures e and f ; the
head and antennae in figure d.
The brachypterous form measures
3 mm. in length, the abdomen being
much broader and more depressed than
in the fully winged form.
The aborted wings, shown in figure
g, are less than 3 mm. in length, with
a spot at apex of clavus and two on the
apical margin, the venation as in the
drawing.
PARASITES.
The species is subject to the attacks
of a dipterous parasite and probably
also to hymenopterous parasites be-
longing to the subfamily dryininae. A
single 9, unfortunately killed in the
cyanide bottle before I discovered the
fact or I might have reared it, exhibited peculiar inflated or oval protections
issuing from each abdominal spiracle,
covered with a dark colored, felt-like
skin, which, on dissecting under the
microscope, I found each to be the re-
cepticle of a puparium of a dipteron
closely allied to, if not, a Cecidomyia. Another year's observatioris will prob-
ably enable me to rear this parasite and settle definitely to what family it be-
longs and it is only mentioned at this
time as an interesting fact in
its life
history well worthy of record.




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