54 



fjernet og nærmet til Mnndaahningen og bidrager 

 derved til Fodens (-)ptagelse. Af de 2 Grene ei' den 

 indre ganske kort, cylindrisk og forsynet paa Spid- 

 sen med 4 cilierede Borster. Den ydre Gren er der- 

 imod af lietydelig Størrelse, omtrent saa lang som 

 Skaftet og temmelig tyk, dog gradvis afsmalnende 

 mod Enden. Den er meget boielig og viser en An- 

 tydning til en tæt Leddeling, idet Kanterne er fint 

 crennlerede. Langs ad dens indre Side findes en 

 E,ad af 15 — 16 stæi'ke, cilierede Svommeborster, 

 hvoraf 2 iidgaar fra selve Spidsen. — (Jverlæben er 

 meget stor og fremspringende, dannende en oval, i 

 en stnm]) Spids endende og i Flngt med Hovedets 

 nndre Flade gaaende Klap, der ganske dækker 

 Mundaabningen nedad. — Kindbakkerne er synlige 

 til liver Side af Overlæben som 2 convexe Frem- 

 spring; men deres Tyggedele synes endnu ikke at 

 være ndviklet. Derimod har enhver .Kindbakke paa 

 den ydre Side et temmelig stort fodformigt Vedhæng 

 af atlang oval Form og forsynet med ialt 8 cilierede 

 Børster, hvoraf 3 ndgaar fra Spidsen, 3 fra en bred 

 Lap af den liagre Rand og 2 fra en noget mindre 

 Lap mellem denne og Spidsen. To Par smaa knnde- 

 formige Fremspning nmiddelbart bag Kindbakkerne 

 antyder Anlægget til de 2 Par Kjæver. Af Bran- 

 chialfodder er der Anlæg til 7 Par, snecessivt afta- 

 gende i Størrelse bagtil. De har alle Formen af 

 simple Tværvnlster, nden Spor af Borster. Hale- 

 enden gaar nd i 2 smaa tils]iidsede Lappe, enhver 

 endende med en enkelt liden simpel Borste. I det indre 

 af Legemet sees tydeligt den med orangefarvet Ind- 

 hold fyldte Tarmkanal, der fortil danner to simple 

 tilrundede Blindsække. Larven bevæger sig meget 

 raskt om i Våndet ved rythmiske Slag af 2det Par 

 Folere, som i dette Stadinm er dens eneste Loko- 

 motionsoro-aner. 



Det Fig. 16 af hildede Larve.stadium er allerede 

 adskilligt videre ndviklet. Legemet er stærkere 

 forlænget og viser en begyndende Sondring i de 3 

 Kropsafsnit. Hovedet er dog endnn meget kort og 

 næsten tvært af knttet fortil. De sammensatte Øine 

 har nn begyndt at ndvikle sig som to convexe Frem- 

 spring ved Basis af Iste Par Folere. I deres indre 

 er der afsat en ringe Mængde rodt Pigment, og der 

 er en svag Antydning til Synselementer. De 2 Par 

 Følere og Mnnddelene forholder sig i alt væsentligt 

 som hos det foregaaende Stailium. Derimod er der 

 indtraadt en kjendelig Udvikling af de bag Mnnd- 

 delene følgende Lemmer. De i forrige Stadinm fore- 

 kommende 7 Par simple Tværvnlster, der rejiræsen- 

 terede Anlægget til IJranchialfodderne, liar nn for- 

 detmeste sondret sig fra Kropssiderne og rager tyde- 

 ligt frem i Form af bncde Plader, der er svasjt ind- 



bristles. Dnring the movements of the oars, these 

 projections are alternateh' brought near to and 

 withdrawn from the oral apertnre thereby assisting 

 in the admis.sion of food. The inner of the two 

 rami is ijnite short, cylindrical, and fnrnished at the 

 point with 4 ciliated bristles. The onter ramns, on 

 the otlier hand, is of considerable .size, aljont as 

 long as the scape, and tolerably thick, though ta- 

 jjering towards the extremity. It is very flexible, 

 and shows an indication of close articnlation, the 

 margins being finely crennlated. Along its inner 

 side, there is a row of 15 or l(i strong, ciliated, 

 natatory bristles, two of which issue from the very 

 ■point. The labrum is very large and prominent, 

 forming an oval, blunt-pointed fiaji extending back- 

 wards as an immediate continuation of the inferior 

 surface of the head, and (piite covering the oral 

 aperture below. The mandililes are visible on each 

 side of the labrum in the form of 2 convex projec- 

 tions, but their masticatory part appears to be still 

 undeveloped. Each mandible has, however, on the 

 outer side, a rather large, oblong oval leg-like 

 appendage furnished with S ciliated bristles, 3 of 

 which issue from the jioint, 3 from a broad lobe of 

 the hind margin, and 2 from a somewhat smaller 

 lobe between the hiiul margin and the ]ioint. Two 

 pairs of small knob-like projections immediately be- 

 hind the mandibles indicate the 2 incipient pairs of 

 maxillæ. There are indications of 6 pairs of bran- 

 chial legs, successively' decreasing in size posteri- 

 orly. They all have the form of simple transverse 

 prominences without a trace of bristles. The end 

 of the tail divides into 2 small pointed lobes, each 

 terminating in a single, small, simple bristle. Within 

 the body may be plainly seen tire intestinal canal 

 with its orange-coloured contents, forming in front 



2 simple, rounded cæca. The larva moves about 

 rapidly in the water with lythmical strokes of the 

 second pair of antennæ, which, in this stage, are its 

 only organs of locomotion. 



Tlie larval stage represented in fig. 16 is already 

 considerably more developed. The body is more 

 elongated, and shows an incipient division into the 



3 sections of the body. The head is still, however, 

 very short and almost abruptly cut ofi' in front. 

 The compound eyes have now begun to develop in 

 the foi'm of 2 convex projections at the base of the 

 first i)air of antennæ. Inside them there is a small 

 quantity of red pigment, and there is a faint indi- 

 cation of visual elements. The two pairs of antennæ 

 and the oral parts are essentially in tlie same con- 

 dition as in the foregoing stadium. On the other 

 hand there is a perceptible development of the limbs 

 behind the oral parts. The 7 pairs of simple trans- 

 verse prominences in the ju'evions stadium, which 

 represented the incipient branchial legs, have now 

 for the most )iiirt separated themselves I'roni tlie 



