CHARACTERISTICS OF LARV.E OF AXOPHELINA. 125 



(o) Thorax. — A difference in hair ornamentation as be- 

 tween Myzorhynchus paludis and others is observable, 

 but we hesitate to assign significance to this. 



(4) Palmate hairs. — These are of decided specific im- 

 portance in regard to: (a) relative size; (6) relation of 

 filament to leaflet; (r) character of filament and of 

 " shoulder" (the term" shoulder " is adopted from Christo- 

 phers and Stephens as meaning the abrupt widening at the 

 point where the filament runs into the leaflet — vide PI. 

 XXIV) ; (d) position in which palmate hairs are found. 



A palmate hair may be found on the thorax and all the first 

 seven abdominal segments, or it may be absent from thorax, 

 first and occasionally second abdominal segments. Great 

 care in examination is necessary before concluding the 

 absence entirely from any segment, because on thorax it is 

 always, and on the first abdominal generally, rudimentary, 

 and in instances close scrutiny with a magnification of x 250 

 or so is required for .certainty where the hair is closely folded 

 in death (c f . PI. XXI, fig. c, 1). If the larva be examined 

 alive the rudimentary hairs are found expanded, as the fully 

 developed, but they are generally quite translucent ; the 

 leaflets, smooth and free from shoulder in most species, do not 

 terminate in any filament, but in smooth, narrow lanceolate 

 extremity (PI. XXI, fig. c, 2). They appear, however, to 

 be functionally active (vide PI. XXIV, fig. I, first and 

 second abdominal segments). 



It is said that these hairs aid the larva in maintaining its 

 horizontal position, and that the long plumose lateral hairs 

 act as balancers. They are, however, liable to be broken or 

 torn off, and the larva appears little, if at all, incommoded by 

 their loss. On one occasion a larva of species paludis (in 

 \vhich the palmate hairs are pigmented and easily discerned) 

 was watched for a considerable time ; there were no balancers 

 on the thorax, two ])roken stumps on the first abdominal 

 segments on one side, and none on the other, nor on the 

 second on either side ; palmate hairs lost from fourth, fiftli, and 

 sixth abdominal segments o)i one side, and from third and 



