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Psyche 4:83-86, 1883.

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PSYCHE.
THE INFLUENCE OF METEOROLOGICAL CONDITIONS ON INSECT LIFE.
BY CHARLES GOLDING BARRETT, PEMBROKE, WALES. [Abstract, by B : Pickman Maim, Washington, D. C., from Entom. mo. mag., June 1882, v. 19, p. 1-8.1
G L The means employed by nature to
keep species within due bounds-check-
ing their inordinate increase or unnec-
essary decrease - are so certain and
reliable in their results, and yet so
obscure and difficult to trace in their
inodes of action, that almost any obser- vations, however slight, which seem to
be reliable as data from which to ascer- tain these means, are interesting and
worthy of being p ~ ~ t on record.
In every district and every climate
there are evidently many species so
peculiarly fitted to it that none of the periodical changes of weather and
temperature materially affect their num- bers, and from these little evidence can be obtained. It is from those species
which only casually and rarely extend
themselves f!om their natural lwmes
into climates unsuitable for them, or
from those which are always to be
found in a given locality, but sometimes rarely and always varying in numbers,
that the most satisfactory evidence n~ust be expected.
lL In the first class of cases an exam-
ple occurred to nle a few years ago
which seems very much to the point.''
From eggs of Dez'ojez'a julchella
received from the south of France some
motlls werc, by great care and assiduity, reared to maturity in England, and
from these were obtained fertile eggs,
which d~dy lmtched. Only about half
a dozen of the larvae seemed to possess
sufficient vitality to feed. These were
fed on potted plants, grown in a sunny
window, where they, covered with
gauze, LLgrew rapidly. feeding with es-
pecial eagerness when the sun was shi-
ning on them. The weather happened to
be fine and the sun hot for two or three weeks just at that time, and one larva
made such progress that in a fortnight it was full-fed, when it spun a very slight cocoon on the gauze and t~irned safely
to pupa. By this time two more larvae
were full-fed and left the food-plant for the gauze, the rest being fully half-
grown, when a change of weather
came, with wind, heavy rain, and a
total absence of s~~nshine. The larvae
were, of course, not exposed to the
rain, but the effect of the change
was that those full-fed made no attempt
to spin up, and the rest ceased to feed, and in a few days they all fell off the
gauze or the plants, dead. After a
fortnight of wet weather it cleared up
and the one pupa produced the moth -
a inale.
G G This seems to supply a key to the
whole 11ist01-y of the eccentric casual
appearances" in England, of this and
many other inhabitants of warmer
climates. In obedience to some s;n-
gular instinct that inlpels insects when becoming too numerous in their natul-a1
homes to enligrate to fresh fields and




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pastures new,' they, contrary to their
ordinaq habits, cross Iand or sea, ar-
riving, of course, very ohen, in some
inhospitable clime, where - if not at
once captured - they very likely soon
fall victims to some pitiless storm of
wind and rain. But supposing both
these risks to be avoided, the moth -
if an impregnated female- in due
course lays its eggs, which most proba-
bly hatch. If the temperature happens
to be lower or the weather wetter than
the natural constitt~tion of the species is able to mdure, the young larvae die
without even attempting to feed: but if
matters are more favourable, the strong- est of them struggle along, and if fairly favoured by the weather a few of them
may reach the perfect state; if quite
unusually favored by the weather a large proportion of them may do so, pro-
ducing those remarkable instances of
the sudden appearance in numbers of
a species usually rare. Such good for-
tune rarely extends to a second semm
and the species becomes a rarity again
or is even probably exterminated, to be
renewed at some future time by the same
instinct of migration. In cases such
as these it appears to me that sunsliine means life, and its absence destruction, to the larvae, and that by this simple
and obvious influence the extension of
species beyond their assigned limits is
practically prohibited.
'4 It also happens sometimes that the
immigrant> foHoGing instinctively its
inherited habit, attemph to produce an
additional hod in the year, over what
the climate will allow." For instance,
pupae of the second brood of Co&s
edusu, in England, showed ill Decem-
ber the yellow color of the wings,
which only shows itself when the
insect is nearly ready to emerge," thus
6 L foliowing inherited habit so as to
hibernate, as they are well known to
do [on the continent of Europe] in the
perfect state, but from insufficient
warmth and sunslhe xere unable to
muster sufficient strength," and died.
Again, in the autumn of 1880, in
which year there had been a wonderful
immigration of Vumssa cardui into
England, evidently a portion of the
vast army that migrated across Europe,
larvae were found tolerably common,
feeding, at the beginning of October,
on young thistle plants, dose to the
pmnd, making their nests among the
radical leaves, all the tall thistles being dead, From some of these larvae two
pupae were obtained, in doors, 17 and
-
20 October, and one imago7 20 Novem-
ber, i4 The rest died. This failure of
instinct on the park of the immigrants
surely explains, in some degree, the
fact that last year [1881 J the insect was more than usually scarce, hardIy any
appearing to have hibernated, and also
why an insect with such power of
increase in a suitable climate is so un- certain and variable in its appearances
in one that is nnfavorable.
'< With reference to the second class
of cases - those in which a species
always present is periodically common
or scarce - much has been written,
excessive rain being usually assigned
as the cause of diminution in numbers,
sunsliine as the cause of increase,
Without doubt these causes act to a




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September4ctober I$å¦J PsYcfJIZ- 85
veiy Iarge extent, large n11mber5 of hr- the high roads were coated to a thick-
vae being actud1y drowned by COII- ness of three or four inches [7.6 to 10.2 tinuecl heavy raiii, and others rendered cm.] fur weeks. liable to disease, but a little evidence 6L The winters of 1879 and 1880 were has come under my notice, pointing so equally cold, indeed, the latter was said distinctly to another influence of equal to be the coldest known here for fifty potency> that 1 think it well worth years, even the sea sands dong the tide recording in detail."
line were covered ankle deep with ice
For many years previous to 1878 miI frozen mow, a sight &rY rareIy seen there 11ad been little or no intense cold on this coast. The first of these three . in Pembrokeshire) owing to the pre- winters [1878-18791 killed dl the dominance 66through each winter of slxubby veronicas and some of the winds from the southeast, south and sumachs, and the tree f~~chsias and west) and especidly the southwest* all
myrtles above the ground.
corning OK a sea kept constantly warm 44 And now I will give the results as by the gulf stream. In many places reprds insects.'' fuchsias standing out of doors had never L~pidoptera which before were ex-
.been cut down by frost within the man-
ceedingly rare became more and more
ary of the inhabitants." Some of these abundant in 1879, 1880. and 1881, until plants had become trees five or six in the Iast year they actually abounded: metres high) with trunks of the size of Specks previous1y restricted to a few a man% leg,
Plai~ts usdiy grown in favorite spots spread nll along the coast greenl~ouses here flourished in the open or over the country. Many Geumeirae air.
'< During these years, very many tuimed LIP which 'had hardly been seen insects of general distribution [in Great before. Britain] continued to be either very
;' But in Noctaue, the improvement
scarce, or confined to exceedingly was the most remarkable) as in that restricted locdities in this district.'' group the scarcity had been most [Particulars given.] L4Noctuae (except marked." [Mentions numerous spe- a few imiversally abundant species) cies which became abundant.] appeared to be almost absent; such a Here we seem to have a direct , dearth of ordinary ~iigh~flying species
example of cause and effect, but I am
1 never knew anywhere before.
not prepared to say that the effect al-
6 6 But in the winter of 1878)
there
ways arises in the same way. I think
was a great change, Persistent north
there can he nu doubt that in the case
or northeast winds, intensely cold, froze of those insects, whose mode of life
everytl~ing up hard, the warm sea air
includes the capacity for hibernation)
was completely expelled7 or if a slight
their constitutio~~ is greatly strengthened change of wind permitted a few clouds
and their chance of arriving at maturity to come over, the rain from them was increased, if the cold of winter is suffi- njstantly conveited into ice, with which ciently severe to induce com$ete tor-




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pidity, undisturbed by warm and spring-
at that time, and, indeed, are not very
like weather at unseasonable times, plentiful in Pembokeshire, they must and this may account for the vast in- destroy many larvae and pupae, having crease in numbers in species which little else to subsist upon. But I believe hibernate in the egg state; it also that the mischief done by all these probably has a strengthening effect on added together does not equal that done those which pass the winter as sinall by the Onisci. social larvae under a silken tent on the 66 During mild winters these crush- ground, or which, Iike the Noctzme, ceous vermin increase and mdti~ly, hibernate in the larva state on the and feed, and grow without check, ti11 ground or among dead leaves! and are in so mild a cIjrnat& they become a per- tempted out to feed by every warm and fect nuisance, pervading everything genial evening. indoors a11d O I ~ It was hardly possible $'On the other haid there can be no to keep them even out of the breeding doubt that rniId winters act directly to cages, where they wodd get introduced
cause the destruction of both hiberna-
when very snud1 and unnoticed-or
king larvae and pupae, in two ways. One
perhaps in the egg state - hunt OLI~ and is by encouraging the growth of mould, , destroy every larva and pupa, and grow which we know attacks them as soon large and plump without ever showing as, from excess of rain or lmmidiiy,
themselves above the leaves and rub-
they become sickly ; the other by per-
bish. Doubtless, their industry out of
initting the continued activity of pre- doors was in the same proportion, and daceous creatures. These are very my impression is that they approached numerous.
Moles cmtinne at work in very new to co~npletely exterminating mild winters, i~~sted of b&ng them- many species that would naturally be selves deep in the gromd; and mice common here. Severe cold seems to are constantly active. These small destroy some of them, for they are not tnammalia destroy great numbers of nearly so numerous now, and it cer- Lepidopterous pupae, and they abound
tainly puts a complete stop to their
in this district, as also do birds during destructive operations during a time the winter in an extraordinary degree. when larvae are most especia1ly helpless As soon as severe cold sets in to the
a11d liable twittack. To this: with other north and east,
the birds come down causes already mentioned, I am inclined in swarms to the open fields and shel- to attribute the extraordinq- increase tercd
hillsides of this district, and it is in n~mbers of so many species during hardly necessary to pint them out as the last three seasons, divi&d%y severe most industrious and, persevering de- winters. The winter now past has
strayers of larvae. Predaceous beetles been mild, and ,-there fore, a further pro- and eaiwigs are geneixtlly on the alert gsessi~e increase cannot reasonably be all through very mild <winters, and al- expected : but I hope that the mischief thmigh they probably do not eat much done in one mild winter may not be



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serious. It is the progressive increase
of destroyers witli the decrease of vic- tims through successive mild seasons
that is really to be dreaded.
L L As a slight corroboration of this
view, I may inention, that while this
district of country is coinpai-atively poor in all the species of which the Iarvae feed and hibernate in any exposed sit~~ation, several species of Noctuae, of whicli
tlie larvae live underground, are always abundant. and the co~~ntrj- is actually
rather rich in those species of Tortri-
cina wliicli feed and llibernate entirely within tlie stalks or roots of plants.
" It is worthy of notice, that there
are a very few species which have
appeared unable to cope witli severe
cold. Lobo$ho~*a vi~etaia was tolera-
bly con~nion here cluring the first three or four years of wliicli I have been
writing, but after tlie first cold winter it became scarce. and has since almost
disappeared ."
SAL1ITARy GLANDS IN BEES.
[Abstract of a dissertation by Pa~ilus Schien)e~~z.] RY GEORGE DITVIMOCK. CAMBRIDGE, MASS.
Paulus Scliieme~~z' dissertation &&uber
das herkoininen des futtersaftes und die speiclieldrusen der biene" . . . [Rec., no. 33371 gives many interesting facts in the anatomy of the 110ney-bee and of other
bees. The beginning of t11 is paper is a historical co~~sideration of the st~bject, with a description of the digestive tract of Apis meZZzjca, in which the author
follows Plateau's view that the proven-
triculus serves to arrest the too rapid
flow of the contents of the crop (or
honey-stomach, as Scl~iemenz here
terms it) into the ventricle. Following
the views of Leuckart, in whose labora-
tory Schiemenz prepared this paper, the
author considers that the ile~1111 of the bees, as of insects in general, has no
other function than that of furnislli~~g a suitable connection bgtween ventricle
and 1-ectiim, and he decides that the
~~utrient fluid used by bees to feed their queen, larvae and dl-ones si~relj does
not come from the ventricle, as has been often supposed. The salivary glands
are next described, and tlieii- seci-etions and histological sti-~~cture discussed, in the order introduced for them bj7 Sie-
bold, i. e.. as LLsyste~~~ I, 11, 111. 11- and v."
The gland of system I (Meckel's su-
prainaxillary gland) is provided with a
reservoir and discharges its strongly acid secretioii by openings. one on each side of the '~å¤cl~l~~ndbliittcl~en [hypopliarynx of Savigiiy]. This gland is alxent in
qLieens and drones. In six species of
bomb?^.^ this s~stein is well de~eloped, and the author describes varioi~s modi-
fications in other bees.
The glands of system 11 (Meckel's glan-
dula $,ul>lingualis) are in the head, just almw its 10~7er or posterior chitinous
walls, and are easiest prepared by first removing system I. and then the brain.
The diRerent eflkrent ducts of the parts



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