194 ILLINOIS STATE ACADEMY OF SCIENCE 



GENERAL SURVEY OF THE FAUNA OF LAKE KNOX— Continued. 



Phylum Arthropoda — Concluded 



Family Corixidae (water boatmen) 



Corixa was found on the surface near the spring at Sta- 

 tion II. 

 Family Notonectidae 

 Notonecta insulata 



This backswimmer was very common in the pond 

 near Station II. 

 Family Acanthidae 



A small green water strider was very common on the sur- 

 face of the water both in the pond and in the slow 

 stream at Station V but has not yet been identified. 

 Family Gerridae 

 Gerris 



This long legged skater is quite commonly seen on 

 the surface of the pond as well as in the stream of 

 the muskrat region. 

 Suborder Homoptera 

 Family Aphidae 



RhophalosipJium 



This aphid was found on the duckweed near the 

 east side of the pond in the fall. 

 Order Lepodoptera 



Land forms were seen on the banks. 

 Nymphalidae 

 Euploeinae 



Anosia plexippus 



The monarch butterfly was found dead on the 

 bank. Larvae were found in May on milkweed. 

 Larvae of viceroy were found on the willow in 

 May also. 

 Pyrrharctia Isabella 



The common black and brown caterpillar was seen 

 frequently on the banks. 

 Order Coleoptera 



Family Dytiscidae 

 Ditiscus 



Larvae of this predaceous diving beetle were 

 abundant. They were found in early March in 

 the mud of the muskrat region. These larvae 

 are commonly known as water tigers. 

 Family Hydrophilidae (water scavenger beetles) 

 Tropistei'mis 



This is a common black beetle often seen on the 

 surface of the pond. 

 Family HaUplidae 

 Peltodytes 



A small yellow beetle seen frequently on the 

 water near Station II. It is swift in its move- 

 ments. 

 Order Diptera 



Family Chironomidae 



CMronomous larvae, commonly known as blood worms, 

 were rather common at Station III. 

 Family Culicidae 



Mosquitoes were common but none were identified as 

 to species. 



