412 NEAV 3'ORK STATE MUSEUM 



bottom, jerking its body rapidly from one side to the other. It 

 appears to be Jiea^ier than water, for sometimes it may be seen 

 to descend quietly, apparently without motion; though, in order 

 to rise, it " wriggles " to the surface. In the full grown larva 

 the head, more or less rounded, is large, usually nearly as wide 

 as the thorax from which it is separated by a narrow neck. 

 The antenna, which arises from a slight prominence a little in 

 front of the eye, consists of a single elongate shaft, with a short 

 terminal joint (which appears to be annulated), several bristles 

 and jointed hairs at the end of the first joint, and a tuft of 

 hairs at about the middle of the shaft. Projecting from the 

 middle of the anterior end of the head is a complex arrangement 

 of hairs which spring from two folded ridges one on each side 

 of the ventral surface of the labrum [pl.43, flg.5]. The length 

 of the hairs varies with the species. Meinert [De Eucepliale 

 Ml/ggeJarreT] speaks of this as a whorl, or rotatory organ, as he- 

 believes that it is by the vibrations of these bristles that the 

 food is directed into the mouth. The greater part of the upper 

 surface of the head is formed of a single plate which Meinert 

 [loc. cit.] calls the dorsal surface of the third metamere. In 

 front of this is a short, broad plate ('' scutum of the second 

 metamere," Meinert), called the clypeus by Giles [2Iosqidtoes]^ 

 [pl.t4, flg.Sc] 



Attached to the anterior m.argin of the latter is the round 

 prominence covered with hairs; this is the labium [pi. 44, fig. 8], 

 or " scutum of the first metamere " [Meinert]. If the front 

 part of the dorsal surface of the head be removed and turned 

 ventral surface uppermost [pl-4o, fig. 5], the two fans or rota- 

 tory organs ,[fig.5f] may be seen, mesad and caudad of which 

 are two tufts of hair projecting caudad. Between the latter is 

 a rounded process on which are from two to four spines. This 

 process together with the two tufts of hair, I believe to be the- 

 epipharynx[e]. 



The eyes are large and placed laterally, behind which and 

 lying close to, may usually be seen a small ocellus. On each 

 side of the mouth opening, ventrad of the fans, are the man- 

 dibles; stout, quadrangular pieces with a number of sharp teeth, 

 at the cephalic end with two stout spines curved mesad, a row 

 of hairs arranged on a ridge or keel overhanging the teeth and 

 another row of long hairs arranged on the posterior margin 

 [pi. 45, flg.l, 2]. A fingerlike process with hair at its apex pro- 

 jects mesad from the mesocaudal margin [fig. 2a.]. Ventrad of 

 the mandibles are the maxillae [pl.43, flg.4a;]. These are also 

 indicated by dotted lines under the mandibles [m] on right hand 

 side, the figure being a dorsal view of the lower half of the head,. 



