AQUATIC INSECTS IN NEW YORK STATU 443 



the Corydalinae. The more important of the distinctiye char- 

 acters of the subfamilies are included in the following tables. 



TABLE TO SUBFAMIIilES 



Adults 

 a Accessory veins of radial sector on tlie front side of 

 vein K3 [fig. 23] ; ocelli wanting; fourth segment of 



tarsi prominently bilobed Sialidinae 



■aa Accessory veins of radial sector on the posterior side 

 of vein E2 [fig. 24, 25, 26] ; ocelli three; fourth seg- 

 ment of tarsi obscurely or not at all lobed Corydalinae 



Larvae 

 a Anal prolegs wanting; lateral filaments only seven 



pairs, and distinctly jointed. .., Sialidinae 



■aa Anal prolegs one pair, provided with claws; lateral 



filaments eight pairs, slightly or not at all jointed. Corydalinae 



Egg masses 



a Eggs always in one layer [pl.51] Sialidinae 



■aa Eggs in more than one layer [pl.52] ...."...Corydalinae 



Eggs 

 a Distal portion of micropylar projection cylindric, 

 twice as long as broad, joined to the egg by a short 



neck [fig.20] '. Sialidinae 



na Distal portion of micropylar projection nearly globu- 

 lar, joined to the egg by a long neck [fig.20] Corydalinae 



Subfamily sialidhmab 



The adult members of this subfamily are all much smaller 

 than those of the Corydalinae; the ocelli are wanting; the acces- 

 sory veins of the radial sector in both pairs of wings arise 

 from R3 and extend forward, giving the insect a very charac- 

 teristic mode of flight; the fourth segment of the tarsi is promi- 

 nently two lobed. 



The subfamily includes a single genus Sialis. 



siAiiis Latreille 

 Besides the characters of the subfamily given above, the fol- 

 lowing additional generic characters should be added: 



Adult. Body and wings black or ferruginous; prothorax 

 quadrangular, almost equal in width to the head, not so long as 

 the mesothorax and metathorax combined; ocelli wanting; an- 



