Article beginning on page 124.
Psyche 8:124-125, 1897.

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[October 1897.
THE NUMBER OF MOULTS IN .INSECTS OF DIFFERENT ORDERS.*
It will be seen from the data here
presented that the number of moults
is as a rule greatest in metabolic insects with the longest lives, and that an
excessive nuniber of ecdyse~ is due to
some physical cause, such as lack of
food combined with low tempesat~~re.
111 Campodea there is a single frag-
mentary moult (Grassi), while the
Collen~bola {Afamoioma $ZumJea j shed
their skin througl~out life. (Sonmer.)
In the winged insects, especially
Lepidoptera? the n~~mher of moults is
dependent on climate. Insects of wide
clistsibution growing faster in warmer
climates conseq~ie~~tly shed their slii~~~ oftener; for example the saine species
inay moult once oftener in tlte southern than in the northern states, as in the
case of CuUosada $mtaethec~~ vvhic11
in West Virgiuia is do~~ble-brooded.
Hibernating larvae mo~ilt once oftener
than those of the suinnxr brood (Ed-
wards). Weniger by rearing the larvae
of Aeiheraeu mylitiu and Eada im-
'
$widis, and ~hkli when reared under
normal conditions actudly 11a17e the six stages, when seared in a warm moist
atmosphere of about 25' C. have but
five stages, i. e., moult but four times. In the hot and moist dimate of Ceylon,
*published in advance from the author's Text book of E~tomology, Any corrections or additions would be tl~aukfully received by the author.
A. mylz'ffa has but five stages.
(P$jcl~e V, p. 28.)
Acsydians moult five times ; Dia-
$h~romerafemoratu hut twice (Riley) ;
a katydid (Micvocentwm retimvds)
moi~lts four times (Comstock) . Mm-
tis ~eJigios~, according to Pagenstecher n~oults seven times* having eight stages, including that of the singular pse-
nymph. Cockroaches ( Pep-i$Zmzetu
ume~ica~a) are said by Nhrlatt to pas8
through a variable number of nloults,
there being sometimes as many as seven
stages.
In the Hornoptem there are in gen-
eral from two to four moults; tliu~ in
Typl~locyl~~~ there are five stages, in
Psocus fo~x? and in Aphis at least three, and in Psylia four du14ing the nymphal
state, Riley states that the nymph of
the fen~ale Cowid, Icerya $z~~+c&Izsz',
sl~cds its skin three times and the male twice. Notwithstancling its slow growth, Riley says, the 17-year Cicada moults
oftener than once a year, and the nm-
bes or larval stages probably an10~1nt6 to twenty-five or thirty in all. The bed-
bug sheds its skin five times; and with
the last mouIt appear the minute wing-
pad8 characteristic of the adult.
In
Conm-hinus sangaisuga these are 'L at
least two larval stages and pupal
stages" (hbrlatt) ,
In the hlay-fly, Chloeon, the num-




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ber of ecdyses is twenty.
The Ncurop-
terous AscuZu$has (Helecomitus) in-
simuZaxs of Ceylon moults three times
before pupating, Among the Mecop-
tera Felt has shown that Punoqikz
~ufesce~s,inonlts seven times.
13 Coleoptera the nor~nal or usual
nu~nber is not definitely known ; Meloe
moults five times ; PhyLonoma~ $uv.c-
iuius, the clover leaf wecvil, moulls
three times, according to Riley, who
has observed that Be9westes v@ims
passes through seven larval stages.
In the breedingjars, with plenty of food and a constant temperature of from 68O to 7Sc F., the larvae cast their first skin in fi-on1 fonr to nine days, the great majority moulting at seven days. Under the same conditions the second skinwas castat f~roni fourtosevendays, the majority moulting at 6ix days; the thit-d skin at from three to six days, the majority moulting at five days; and the fourth skin a( from three to six da!s, the majol-ity moulting at five days; the fifth skin at from five to seven days, and the sixth skin at six days. There are thus seven lar~al stages. (Report for 1885, p. 260.1
Riley has ascertained that by rearing iso- lated larvae of Teue&~io ~noZito~, one after being kept nearly a year had moulted eleven tirqes, when it died. A second larva hatched June 5, had moulted twel~e times hy June 10th of the following Jear (~877)~ vshen it also died. Of T. O~.K~LY!IS three larvae were reared to the imago state. One moulted
eleven times by August 30th of the same
year, pupated Jan. zoth, ~Siv, and finally be- came a beetle Feh. 7, 1877. The other two both moulted twelve times and reached the imago state Feb. 18 and March 9th respec- tively. ,'All were, as nearly as possible, under like conditions of food and surround- ings, and in all casesihe moult that gave the pupa is not considered among the larval
moults:'
Two larvae of the museum pest (T~ogo-
dewaa La~sde) wei-e kept by Rilej in a
tight tin box with an old silkuror~n cocoon, c' They were half grown when placed in the box. On Novetnbe1-8th, 18Sq therexel-e in the box twentyeight larva skins, all very much of a size, the larva having apparently grown but little. Tl~e skins were I-e~noved and the box closed agzzin as tightly as
possible. Recently, or after a lapse of two years, the box was again opened and w.e
found one of the larvae dead and shrivelled up; hut xhe other was living and apparet~tl,~ not changed in appearance. There were
fifteen larva skins in the box. We cannot tell when the one larva died, but it is certain that within a littlemore th~n three and a half years, two larvae shed not less than forty- three skins, and that one larva did not, during that time, appreciably increase in size. '' We know of no observations which indicate the nornial or average length of life, or number of moults in either Tenebrio or Trogoder~na, but it is safe to assume from what is known, in these respects, of allied species, that in both :he instances here referred to, hut particula~dy in the case of Trogoderma, de- velopment CVRS reta~ded by insufficient nutri- tion and that the frequent monlting and slow growth resulted therefroin and were corre- lated."* Further observations such as tbesc are greatly needed.
Of the Siphoi?aptera the common cat
and dog flea (Pule2 sewatz'ce@s) modts
three times before pupating (Howard).
In Lepidoptera the usual or average
number of moults is four: but the number varies considerably, the greatest number yet known occurring in Phyvvarctz'a
isdeZZa which, Dr. Dyar infornls me,
moults tcn times.
From Dyar's observations it appears
that there are usually five larval stages, *American Naturalist, mii.
May 1883, pqes 547-548,




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126 F's 2'Tl??.?%. [October 1697
but six and seven stages are not infre-
quent, while there are eight in Scepsis
and Apatelodes and nine and teu in
Arctians, while the European Nola
centonalis n~oults nine times, other
species sheddi~>g their skins six tirlles (Buckler)< (Psyche, v, pages 420-422).
CaUosamiu $randha moults but three
times as EX rulc. 07,gyia antigucz was
fo~~nd by Hellins to moult froin three to five times, Riley found that in 0. Zeuco- stigma the males moult four times, the
female four but sometimes five times,
whilc Dyar states that in 0. gzdosa the
male larvae moult three or four times,
the female always four times ; while in
0. antipa there are six stages, and
in the femalc seven. Litl~ocolletis,
Chambers thinks, as a rule n~oults eight times, Comstock thinks L. hamadrya-
~ ~ Z Z L Z casts its skin seven or eight times. In the blow-fly (Calliphora) Leuckast
and Wcis~nann havcinferred at least two
moults, while Weisinann suspects that
there are as many as four., In Musca
domestz'ca we have observed that the
larva moults three timcs ; in Oestridae
there are three larval stadia (Brauer) . In Corethra these are four lar~al moults,
and Miall thinks there are probably as
many. In the phytophagous Hymenop-
tera there me three moults or fonr larval stages in Ne7fi~hf~ erichsonii, but Dyar informs me that less than four stages in saw-fly larvae is very rare, that he has only one record of less than five, and that that is doubtful ; five for Nematid, six and scven fofotl~crs, is cc~tainly the rule. The highest I have is the indication
of eleven stages for Ha?,$i$kom.\ va~i-
anus " (Can. Ent., xxvii, p. 208).
In Bombus we have observed five differ-
ent sizes of larvae and hence suppobe the least number of ecdyses is five, while
we are disposed to believe that this
insect as well as wasps and bees in gen- eral shed their skins as many as ten
tinies during their entire existence.
The honey bee, Cheshire thinks, since
hc has found the red and rupt~~red pel-
licles, probably mo~~lts six times before it spins its cocoon, or passes into the
semipupa condition. (Bees and Bee-
Kceping, p. 20).
As to the causc of the great number of
moults in the Arctians and the hcetles
experimented with by Riley, it would
seem that cold and the lack of food dur- ing hibernation were the agents in Arc-
tians, and starvation or the lack of food in the case of the beetles, such cause
pscventing growth, though the hypo-
dermis-cells 1-etaincd their activity.
DIPTERA OF THE ORGAN LMOUNTAINS IN SOUTHERN NEW MEXICO. - I.
BY C. H. TYLER TOWXSEND, LAS CXTJCES, SEW MEXICO. In Schce, for Dec. 8, 1893, the Organ Mountain rangc, which lies in writer gave a general description of the the Doiia Ana county, some fificen miles



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