SIALID.E. SIALIS. 133 



head large^ somewhat orbiculate ; eyes moderate ; mandibles stout, curved ; 

 antennae longish, somewhat setaceous, four-jointed; thorax triarticulate ; 

 abdomen setose, tail conic ; legs long, setose ; pupa folliculate. 



Of this family one genus only is indigenous, viz. — 



Genus XXV.— SIALIS, Latreille. 



Antenri(E short, setaceous, composed of numerous simple joints, the basal one 

 robust : pa/p filiform, the basal joint somewhat elongate-cylindric : man- 

 dibles small : head moderate, as wide as the thorax : eyes prominent : ocelli 

 wanting: collar ample : meso- and meta- thorax both transverse, tubercular: 

 wings deflexed during repose, all coarsely reticulated, anterior rather the 

 largest ; nervures variable : legs shortish : tibiw with two very short spurs 

 at the apex : tarsi five-jointed, the last joint but one bifid. Larva active, 

 aquatic, elongate-conic, depressed, furnished with six elongate bristly legs, 

 two somewhat longish four-jointed antennae, and stout curved mandibles; 

 the thorax is triarticulate, the abdomen furnished on each side of the seven 

 first segments with a branchial appendage ; terminal segment elongate, 

 conic, setose at the apex : pupa quiescent, reposing in a cocoon, removed 

 from the water. 



The insects of this genus have the wings deflexed, reticulated with 

 strong nervures, which frequently vary in the two sides of the same 

 individual ; the penultimate joint of the tarsi is bifid, and the insects 

 are destitute of ocelli: — one indigenous species only is known, which 

 frequents the borders of rivers, &c. 



Sp. 1. lutarius. Niger, ohscurus, alisfuscis nervis nigris. (Long. corp. 4 — 7 

 lin. j Exp. Alar. 9 lin. — 1 unc. 7 lin.) 



•f Sp. 2. flavilatera. " Alis reticulatis, cauda inermi thoracis lateribus Jlavis." — 



Linne. 

 Phry. flavilatera. LinnL—Berkenhout {\)—Steph. Catal. 321. No. 3684, note. 



Wings somewhat cinereous, reticulated ; nervures fuscous and closely 

 reticulated, especially towards the outer margin, which is dilated; body 

 wholly blackish ; antennae half the length of the body ; tail simple, without 

 prominent styles ; collar anteriorly and posteriorly yellowish. 



I have never seen a specimen of this insect : whether, therefore, this is its true 

 location I am not prepared to say; but, from the above Linnean definition, 

 such appears to be the case. 



This insect was introduced by Berkenhout amongst our indigenous species, but 

 as no example has occurred in any of the numerous collections — above 250 — 

 that have fallen under my inspection, I conceive its introduction must 

 originate in a mistake. 



