103, 
Folere og delvis ogsaa Mandibularfodderne, hvorved 
snart Ryg- snart Bugside vendes opad. 
Et noget senere Stadium er fremstillet Fig. 3 
fra Bugsiden. Larven har nu naaet en Lengde af 
0,47 mm og har Legemets bagre Afsnit end mere 
forlenget, skjondt fremdeles uden Spor af Lemmer. 
De terminale Fortsatser, som aabenbart svarer til 
Haleklorne hos det voxne Dyr, har strakt sig be- 
tydeligt i Lengde og er skilt ved et dybt Indsnit, 
i hvis Bund Analaabningen er beliggende. I det 
indre af Overleben sees flere meget tydelige celle- 
agtige Legemer, aabenbart af kjertelagtig Natur, og 
dens terminale Fortsats er nu fuldkommen saa lang 
som den proximale Del af Overleben og skraat 
nedadrettet. Mandibularfoddernes Rodstykke har 
sondret sig skarpere fra Legemet og forlenget sig 
indad mod Mundaabningen, hvorved det nu meget 
tydeligt viser sig at representere Kindbakkernes 
Corpus. Selve Lemmerne synes dog ikke at have 
undergaaet nogen vesentlige Forandringer i sin 
Structur. Legemet er i dette Stadium betydelig 
mere gjennemsigtigt end i de 2 foregaaende Stadier 
og neesten vandklart, saa at den med gulfarvet 
Indhold fyldte Tarmkanal med stor Tydelighed 
skinner igjennem de tynde Integumenter. 
Fig. 4 fremstiller (fra Rygsiden) et betydelig 
senere Stadium, som er nerved at skifte Hud. Lar- 
ven har nu en Lengde af 0,65 mm. og har under- 
gaaet flere vesentlige Forandringer. Legemet er 
idethele temmelig langstrakt, og det bagre Afsnit, 
uden at regne de terminale Fortsatser, dobbelt saa 
langt som det forreste, fra hvilket det er sondret 
ved en meget tydelig Indknibning. I det indre af 
Hovedet viser sig nu det forste Spor af de sammen- 
satte Gine i Form af 2 smaa, endnu vidt adskilte 
Pigmentpletter, der ligger til hver Side og noget 
ovenfor det enkle Mie. Lereboullet har ment, at de 
sammensatte Mine dannedes ved en Afspaltning fra 
det enkle @ie, hvad der er aldeles urigtigt. De 
dannes ganske uafhengigt af det enkle Mie, der 
baade hvad Storrelse og Form angaar, er fuldkom- 
men uforandret. Af Lemmerne er Iste Par fuld- 
kommen af samme Udseende som hos de tidligere 
Stadier, men synes at vere rykkede noget lengere 
ned paa Bugsiden. Paa 2det Par har den basale 
Fortsats klovet sig i Enden i 2 borsteformige, tet 
cilierede Spidser, og den bagre Gren har faaet en 
Svommeborste flere paa Spidsen. Mandibularfodderne 
viser nu alle sine 3 Led meget tydeligt begraendsede, 
og den fra nestsidste Led udgaaende Borste har 
than behind. The larva, which is now 0.36 mm. in 
length, swims ahout with tolerable rapidity in the 
water, with rhythmical strokes of the 2nd pair 
of antenne, and partly of the mandibular legs, 
whereby now the dorsal, now the ventral surface is 
turned uppermost. 
A somewhat later stage is represented in fig. 3, 
from the ventral surface. The larva has now 
attained a length of 0.47 mm. and has the posterior 
section of the body even more elongated, though 
still without a trace of limbs. The terminal pro- 
jections, which evidently answer to the candal claws 
in the adult animal, have increased considerably in 
length, and are separated from each other by a 
deep emargination, at the bottom of which the anal 
aperture is situated. Inside the labrum are visible 
several very distinct cellular bodies, evidently of a 
glandular nature; and its terminal projection is 
now fully as long as the proximal part of the 
labrum, and directed obliquely downwards. The 
basal part of the mandibular legs has become more 
sharply divided from the body, and is produced 
inwards towards the oral aperture, thereby showing 
very clearly that it represents the body of the 
mandibles. The limbs themselves, however, do not 
seem to have undergone any essential change in 
their structure. The body in this stage is consider- 
ably more transparent than in the two preceding 
stages, being almost as clear as water, so that the 
intestinal canal, with its yellow-coloured contents, 
shows with great distinctness through the thin 
integuments. 
Fig. 4 represents (from the ventral surface) a 
very much later stage, when the animal is about 
to cast its skin. The larva now has a length of 
0.65 mm., and has undergone several important 
changes. The body is on the whole rather elon. 
gated, and the posterior section, not including the 
terminal projections, is twice as long as the ante- 
rior, from which it is separated by a very distinct 
contraction. Inside the head, the earliest traces of 
the compound eyes now appear in the shape of two 
small, and as yet widely-separated spots of pigment, 
lying one on each side, and somewhat above the 
ocellus. Lereboullet thought that the compound 
eyes were formed by a splitting off from the 
ocellus, a theory which is altogether incorrect. 
They are formed quite independently of the ocellus, 
which, both as regards size and shape, is altogether 
unchanged. The Ist pair of limbs is of exactly the 
same appearance as in the earlier stages, but they 
seem to have moved a little farther down on the 
ventral surface. In the 2nd pair, the basal projec- 
tion has divided at the end into 2 bristle-like, thickly 
ciliated points, and the posterior ramus has acquired 
another natatory bristle at the point. The man- 
dibular legs now show all their 3 joints very 
