ENTOMOLOGIST AND BOTANIST. 



229 



ON THE TRANSFORMATIONS OP SIMULIDM. 



UY liAllON U. OSTEN SAIKKN, XKW YCKK - 



[Fig. US.J 



Explanation of Fi<;lkk 145 —(n) Larva ft-om a side viuw, 

 enlarged, the Imir-line aI>ove showing natural size; (b) 

 same, from a back view; (c) pupa, ventral view, enlarged; 

 (rf) same, dorsal view; (flpuiial puurh, enlarged, the liair- 

 linc ehowing natural size — After Vcrdat. 



Several excellent observers have studied the 

 natural liistory of this genus, which, except in a 

 lew doubtful points, may be considered as fairly 

 elucidated. The foUowinf-- account has been 

 prei)ared by comparing my own obsei-vations, 

 made upon a species which I found in the envi- 

 rons of Washington, with those of Verdat and 

 others. In this account, the discrepancies be- 

 tween authors have been carefully noted, in 

 order to draw the attention of future observers 

 to those points which deserv(^ to beinvestigate<l. 

 It must be borne in mind, however, that some 

 of tliese discrepancies may be due to the fact that 

 the observed larva^ belonged to difl'erent species 

 of the genus SimuUwii. 



The lai-va> are frequenth' found in small streams 

 of running water, in large societies, lastened by 

 their tails to stoues or to the leaves or stalks of 



water plants. They are about 0.35 of an inch 

 long, subcylindrical, attenuated in the middle, 

 inciassated towards both ends; the latter third 

 of the Iiody is stouter than the antei-ior tliird, 

 and almost club-shaped; head sulxiuadrate. yel- 

 lowish, with a pair of small. ai)proximate lilack 

 ilots on each side. Verdat took them for eyes, but 

 1 did not discover the slightest convexity in fheni. 

 Tliey are evidently below the horny shell of the 

 liead. Antennae slender, subuliform, a|iiiareiitly 

 four-jointed. Epistoma horny, subtriangular; 

 upper lip tieshy, fringed with long, delicate hairs ; 

 its ordinary position is not horizontal, but almost 

 vertical, at right angles with the upper surface 

 of the head and iis if lapping over the oritice of 

 the (esophagus; (it can be perceived only by 

 looking in the direction of the axis of the body, 

 as it is concealed between the other parts of the 

 mouth) ; between the mandible and the epistoma 

 and close by the antenme the remarkable flabelli- 

 form organs, peculiar to this larva, are situated; 

 they consist of a stout st(!m bearing a fan of 

 thirty-live or forty delicate horny rays, each of 

 the shape of a very long, slender scythe; they 

 olien and close like a fan ; when closed, the tip 

 of tliis fan is inside of the mouth and touches the 

 tip of the mandibles ; its opposite end forms an 



[Fig. Uli.l 



7 



E.MT.ANATION OF FlcliBK IJfi — (a) Head of larva, Irnni un- 

 ikr.-.ide; (ii) its nuindible; (c) maxilla; (r) under li|>; if) 

 upjier lip — all enlarged; (rf) larva natural size, attacliVnl 

 tci a iilimt; (r/) pupa natural size, within its pouch —yl/(cv 

 Verdat . 



angle or knee with the stem. They may be 

 compared to the antenna; of the dlelolonthidw, 

 only the rays are much more numerous. The 

 mandibles consist of a pale-colored, tipparently 

 tieshy, basal piece, with a tuft of hairs on the 

 inside, and to their upper extremity are fastened, 

 •1st, a small, horny, black tooth, having the shape 

 of an ordinary mandible, bitid at the tip. and 

 with a very minute projection inside of (his in- 

 dentation; 2d, a brush of hairs, or perhaps of 

 scythe-shaped organs analogous to those form- 

 ing the fan. The maxilke consist of a stout, 

 fleshy basal i)iece, an elongated apptirently two- 

 jointed palpus (tirst joint cylindrical, second 

 short, rudimeiil;u-y), ;md an internal, rounded, 

 thumb-shaped lobe, bearing tufts of hairs on both 



