AQUATIC INSECTS OF FRESHWATER 



Stones in the streams and feed on the larvae and nymphae of May-flies, 

 Stone-flies and other aquatic insects. The larval stage lasts three months 

 and longer, but the pupal stage is quickly passed, and in less than a month 

 after the larva leaves the water to malce a cell for itself nearby, in which 

 to undergo the metamorphosis, the adult insect or imago appears. 



Some of the 

 common species 

 of Sialiadae, of 

 smaller size, the 

 Alder-flies, or 

 Chauliodes, are 

 C.pecticornis, hav- 

 ing greyish wings 

 and featherlike 

 antennas, and C. 

 serricornis of a 

 brownish - black 

 color with white- 

 spotted wings. 

 Four other species 

 are not quite so 

 generally distrib- 

 uted. All the 

 Dobson larvae are 

 carnivorous and 

 destructive to 

 small fishes and 

 snails. 



May-Flies or 

 Shad-Flies be- 

 long to family of 

 Ephemeridae, sig- 

 nifyinglasting but 

 a day. They have 

 delicate m e m- 

 branous wings, 

 with a fine net- 

 work of veins, the 

 fore wings larger 

 than the second 

 pair, which latter 



FIG. 213. 

 J . May-fly, Heptagtnia pulchella, of the family Ephemeridae. 

 2 and 3. " 5««s />y^ff!<ra, lateral and dorsal views. 



4. Stone-fly, Leuctra tenella, of the family Plecoptera. 



5. Caddice-fly, Phryganea intertufta, of the family Hydropsychidae. 



Enlarged x 6. 



6. " Phryganea interrupta, Imagos at rest. Natural size. 



7. ** larva. Enlarged x 5. 



8. " pupal case. Enlarged x 4. 



9. Black-fly, Roederiodes juncta, of the family Empididae. Enlarged x 10. 



10. " larva. Enlarged x 5. 



11. " pupa. " X 5. 



12. " " in case. Enlarged x 5. 



13. Buffalo-fly, Simulium venustus, of the family Simuliidse. Enlarged x 5. 



Group of pupae. 



14. " larva. Enlarged x 6. 

 H. ** Natural size. 



259 



