'Animals of the Mississippi Bottoms near Qiiincy. 179 



9. Libellulina, nymph. 



A stout-bodied, pale brown nymph with scattered specks 

 and spots of brown. Legs annulate with brown. Segments 8 

 and 9 of the abdomen with large lateral spines ; no dorsal 

 hooks or tubercles. The digestive tubes of several examples 

 contained a good many microscopic plants and animals, 

 together with a brown granular matter which I think had been 

 gathered from the bottom. Extremely common in the upper 

 part of Cedar Creek ; the only young of this group taken there. 



10. Lihellulina, nymph. 



With a general resemblance to number 9, but rougher and 

 the markings very obscure. A pair of tubercles between the 

 eyes. A series of erect cultriform hooks on the middle of the 

 abdomen, above. From the alimentary canal of one specimen 

 a small mite was taken. Others examined did not contain 

 food. Common and widely distributed. 



Localities : Harkness Slough, Bailard Slough, Willow 

 Slough, Lily Lake, Long Lake, Broad Lake. 



11. Lihellulina^ nymph. 



Much like 10, but with smoother body, and lacks the 

 cephalic tubercles. A distinct dusky bar between the eyes. 

 Legs annulate with dusky. Dorsal spines not cultriform, and 

 not elevated behind. Not as common as the two preceding. 



Localities: Lily Lake, Long Lake. 



12. Lihellulina^ nymph. 



Similar to number 10, and possibly the young of the same 

 species. Tubercles of head relatively much larger. Dorsal 

 spines tuberculiform, erect. Body more slender, nearly uni- 

 form blackish brown. 



Two small examples from Willow Slough. 



ORDER EPHEMERID.E. (Mat Flies.) 



The adults of certain species of this group are familiar to 

 any one who has visited our rivers in July. They blacken the 

 willows at the water's edge and cause the limbs to droop, in 

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