Scientific American Supplement, No. 363, December 16, 1882

Part 3 out of 3

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ON THE BIOLOGY OF GONATOPUS PILOSUS Thoms--Professor Josef Mik, in the
September number of the _Wiener Entomologische Zeitung_ (pp. 215-221,
pl. iii), gives a most interesting account of the life history of the
curious Proctotrupid, _Gonatopus pilosus_ Thoms., which has not before
been thoroughly understood. Ferris, in his "Nouvelles excursions dans
les grandes Landes," tells how, from cocoons of parasitic larvae on
_Athysanus maritima_ (a Cicadellid) he bred _Gonatopus pedestris_, but
this he considered a secondary parasite, from the fact that it issued
from an inner cocoon. It appears from the observations of Mik, however,
that it was in all probability a primary parasite, as with the species
studied by the latter (_G. pilosus_) the larva spins both an outer
and an inner cocoon. The larva of _Gonatopus pilosus_ is an external
parasite upon the Cicadellid _Deltocephalus xanthoneurus_ Fieb. The eggs
are laid in June or July, and the larvae, attaching themselves at the
junction of two abdominal segments, feed upon the juices of their host.
But one parasite is found upon a single Cicadellid, and it occasionally
shifts its position from one part of the abdomen to another. Leaving its
host in September, it spins a delicate double cocoon in which it remains
all winter in the larva state, transforming to pupa in May, and issuing
as an imago in June.

It will be remembered that the female in the genus Gonatopus is
furnished with a very remarkable modification of the claws of the front
tarsi, which are very strongly developed, and differ somewhat in shape
in the different species. It has usually been supposed that these claws
were for the purpose of grasping prey, but Professor Mik offers the more
satisfactory explanation that they are for the purpose of grasping the
Cicadellids, and holding them during the act of oviposition.

It is interesting to note that there is in the collection of the
Department of Agriculture a specimen of _Amphiscepa bivittata_ Say,
which bears, in the position described above, a parasitic larva similar
to that described by Mik. It left its victim and spun a white cocoon,
but we failed to rear the imago. It is probably the larva of a
Gonatopus, and possibly that of the only described American species of
the genus, _Gonatopus contortulus_ Patton (_Can. Ent._, xi p. 64).

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numerous species of this family, we know the development and earlier
stages of only one species, viz, Fuller's rosebeetle (_Aramigus
Fulleri_[1]). A few other species have attracted attention by the injury
caused by them as perfect insects. They are as follows: _Epicoerus
imbricatus_, a very general feeder; _Pachnoeus opalus_ and _Artipus
floridanus_, both injurious to the orange tree. Of a few other species
we know the food-plants: thus _Neoptochus adspersus_ feeds on oak;
_Pachnoeus distans_ on oak and pine; _Brachystylus acutus_ is only
found on persimmon; _Aphrastus toeniatus_ lives on pawpaw (but not
exclusively); _Eudiagogus pulcher_ and _rosenschoeldi_ defoliate the
coffee-weeds (_Cassia occidentalis_ and other species of the same
genus). Two very common species, _Pandeleteius hilaris_ and _Tanymecus
confertus_, appear to be polyphagous, without preference for any
particular plant. Very recently the habits of another species, _Anametis
grisea_ Horn, were brought to our knowledge by Mr. George P. Peffer, of
Pewaukee, Wis., who sent us specimens of the beetle accompanied by the
following communication: "The larger curculio I send you is working
around the roots of apple and pear trees, near the surface of the ground
or around the union where grafts are set. I found fifteen of the larvae
on a small tree one and a half inches in diameter. The beetle seems to
lay its eggs just where the bark commences to be soft, near or partly
under the ground. The larvae eat the bark only, but they are so numerous
as to girdle the tree entirely in a short time."--_C. V. Riley_.

[Footnote 1: Vide Annual Report Department of Agriculture, 1878, p.

locusts in Cyprus and the Dardanelles, as we learn from the Proceedings
of the London Entomological Society, are much infested with the
parasitic larvae of _Bombyltidae_, though these were previously not
known to occur on the island. This fact shows that the habit which we
discovered among some of our N. A. _Bombyliids_ recurs in other parts
of the world, and we have little doubt that careful search among locust
eggs will also reveal the larval habits of some of the _Meloidae_ in
Europe and elsewhere. Indeed, notwithstanding the closest experiments
of Jules Lichtenstein, which show that the larva of the Spanish
blister-beetle of commerce will feed on honey, we imagine that its more
natural food will be found in future to be locust eggs. The particular
_Bombyliid_ observed by Mr. Frank Calvert destroying locusts in the
Dardanelles is _Callostoma fascipennis_ Macq., and its larva and pupa
very closely resemble those of _Triodites mus_. which we have studied
and figured (see Vol. XV., pl. vi.). We quote some of Mr. Calvert's

"On the 24th of April I examined the larvae in the ground; the only
change was a semi-transparent appearance which allowed of a movable
black spot to be seen in the body. On the 8th June about fifty per cent.
of the larvae had cast a skin and assumed the pupal state in their
little cells: the color yellowish-brown, darkening to gray in the more
advanced insect. About one per cent. of the cells, in which were two
skins and an aperture to the surface, showed the perfect insect to have
already come out of them. A gray pupa I was holding in my hand suddenly
burst its envelope, and in halt a minute on its legs stood a fly, thus
identifying the perfect insect.... I found the fly, now identified,
sucking the nectar of flowers, especially of the pink scabious and
thistle, plants common in the Troad. (Later on I counted as many as
sixteen flies on a thistle-head.) The number of flies rapidly increased
daily until the 13th, when the ground appeared pitted all over with
small holes from whence the parasite had issued. A few pupae were then
still to be found--a larva the rare exception. The pupal state thus
seems to be of short duration. It was very interesting to watch the
flies appearing above ground; first the head was pushed out; then, with
repeated efforts, the body followed; the whole operation was over in
two or three minutes; the wings were expanded, but the colors did not
brighten until some time after. Occasionally a pupa could not cast
off its envelope, and came wriggling out of the ground, when it was
immediately captured by ants. Unfortunate flies that could not detach
the covering membrane adhering to the abdomen, also fell a prey, as
indeed many of the flies that could not get on their legs in time. The
flies for the first time 13th June, were seen to pair, but this rarely."

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The house sparrows were first brought to New York city in 1862. They
might have been introduced in consideration of the scientific usefulness
of the experiment; but the importation was made solely in view of the
benefit to result from their immense consumption of larvae.

I have long observed peculiarities in their acclimation which are hardly
known at all, and which must have a scientific importance. The subject
might also be worthy of general interest, so numerous and familiar have
the sparrows become all over our country.

Walking on Fifth avenue, or in the parks of the city, during the
breeding season, one's attention is repeatedly attracted by the pitiful
shrill call of a sparrow fallen on the pavement upon its first attempt
at flight, or by the stronger note of a mother sparrow, sharply
bewailing the fate of a little one, killed by the fall, or dispatched
alive by the cat.

Should we take and examine these little weaklings, we should find
generally that they are at a period when they normally should have the
strength for flight, and we should also find that they are almost always
of a lightish tint, some with head white, others with streaks and spots
of white on the tail or back, and occasionally one is found entirely
white, with red eyes--a complete albino. It is an accepted fact that the
city-sparrow is everywhere of a lighter color than that of the country.
But here the greater lightness exists in so many cases, to such
a degree, and particularly in female sparrows, that it should be
discussed, at least in part, under the head of albinism.

That so many which lack the muscular strength in their wings should be
so generally affected with albinism, is a significant fact to those
interested in this phenomenon.

Many hold, with Darwin, that this extraordinary want of coloring matter,
occasionally met with in all animals, is not to be regarded as an index
denoting an unhealthful condition of the animal. That it is so often
united in the young sparrow with physical inability, argues favorably
for those who bold a different view.

In my observations, what has struck me as a most curious fact, and what
I have found to be generally ignored, is that this wide-spread albinism
and general weakness of our acclimated house-sparrow are not found among
its progenitors.

Throughout several sojourns that I made in Europe. I searched for a
token of the remarkable characteristics existing here, but I never
succeeded in finding one in England, France, or in Germany, nor have I
met an observer that has.

This albinism and weakness, existing simultaneously to such an extent in
our young house-sparrows, are evidently the result of their acclimation.

The hypothesis that our now _numerous_ sparrows, being descended from
a _few_ European birds, and that, probably, continual and close
reproduction among individuals of the same stock, as in the case of our
original _few_ sparrows, has encouraged weakness in the race, can hardly
serve as an explanation of this phenomenon, because the sparrow is so
prolific that, after a few years, so many families had been formed that
the relation between them became very distant.

The reason for the greater proportion of albinism found in the young is
obvious; the young sparrows affected with albinism, lacking usually the
physical strength to battle their way in life, meet death prematurely,
and thus a very small proportion of the number is permitted to reach
maturity, while those that do owe it to some favoring circumstance. Many
are picked up and cared for by the public; and among those to whom these
sparrows generally owe such prolongation of life are the policemen in
our public parks, who often bring these little waifs to their homes,
keeping some, and sending others out into the world, after caring for
them until they have acquired the sufficient strength. However, almost
all of these albino-sparrows are picked up by the cat, and immediately
disposed of to the feline's physical benefit. They form such a prominent
diet among the cats near Washington Park, where I live, that, upon the
removal of some of our neighbors to the upper part of the city, it was
noticed that their cat became dissatisfied and lean, as sparrow-meat is
not to be found so extensively there, but it finally became resigned,
finding it possible to procure about three sparrows daily.

And here attention should be called to the method employed by our cats
to catch not only the weak, but fine, healthy sparrows as well; it ought
perhaps to be looked upon as a mark of intellectual improvement, for
originally their attempts consisted chiefly in a very unsuccessful
giving chase to the flying bird, whereas the cats of to-day are skilled
in a hundred adroit devices. It has often been a source of enjoyment to
watch their well-laid schemes and delicate maneuverings.

What wonder then, with such dainty fare at his disposal, that the cat is
often found to have become indifferent to rats, and even to mice?

There are several notable changes, no more desirable than the foregoing,
which have been caused by the introduction of the house-sparrow. The
only positive benefit which occurs to me is that the measuring worm,
which formerly infested all our vegetation, is now very nearly extinct
through the instrumentality of the sparrows. A pair of these, during the
breeding-season, destroys four thousand larvae weekly.

In some places, complaints are made that their untidy nests mar the
appearance of trees and walls.

The amount of havoc in our wheatfields created yearly by them is
enormous. Their forwardness and activity have driven all other birds
from where they have settled, so that the hairy caterpillars, which
sparrows do not eat and which used to be extensively consumed by other
birds, are now greatly on the increase, probably the only creatures, at
present, enjoying the domestication of the sparrow in this country....
I have also to remark that the sparrows here betray much less pugnacity
than in Europe.--E.M., M.D.

* * * * *

It is stated in the _Chemical Review_ that recent analyses of the water
from the _Holy Well_ at Mecca, which is so eagerly drunk by pilgrims,
show this water to be sewage, about ten times stronger than average
London sewage.

* * * * *


In looking over the excellent article of Professor S. M. Haupt, in the
SCIENTIFIC AMERICAN SUPPLEMENT, No. 360, on the subject of finding the
meridian, I discovered that one important step is not given, which,
might prove an embarrassment to a new beginner.

In the fourth paragraph, in the third column of page 5,748, he says:
"Having now found the altitude, correct it for refraction, ... and the
result will be the latitude."

It will be observed that this result is only the true altitude of the
star. The _latitude_ is found by further increasing or diminishing this
altitude by the polar distance of the star.

This paper will be of great value to engineers and surveyors, for the
elementary works on surveying have not treated the subject clearly.


Ferrysburg, Mich.

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