Animals of the Mississippi Bottoms near Quinoj. 101 



labium of which differs from that of all the preceding larvae in 

 lacking the median tooth. Its condition would not permit of 

 more extended comparison with the others, and it may prove 

 the same as (3). 



Ceratopogon^ larva. 



This is an extremely slender, transparent larva, resembling 

 a vinegar eel, with eight long hairs radiating from the pos- 

 terior body segment. It has been noted by Professor Forbes 

 in the stomachs of fishes. 



Common among algie in Lily Lake August 15. 



ORDER COLEOPTERA. (Beetles.) 



The aquatic members of this order of insects frequently 

 have some or all of their limbs flattened and fringed to fit them 

 for rajnd locomotion in the water. Others show little in their 

 structure that is adaptive to aquatic life, and simply creep 

 about under water or cling to submerged vegetation much as a 

 terrestrial beetle might. They are all, when adult, obliged to 

 come to the surface for air, which they take and hold in 

 bubbles by means of antennae, wing-covers, or legs. Some of 

 the larvie also come to the surface for air, but others are pro- 

 vided with special respiratory structures by means of which 

 they are enabled to get oxygen from water. Only the larvae 

 and adult beetles are aquatic. The larva quits the water when 

 ready to become a pupa, and commonly burrows into the 

 neighboring banks, where it excavates a small chamber in which 

 it pupates. The adult on emerging returns at once to the 

 water. 



Many beetles in both larval and adult stages are very de- 

 structive to small aquatic animals of other kinds, and even 

 attack fishes of considerable size. Tadpoles many times larger 

 than these insects are often devoured. Some eat only the 

 dead of other insects, while still others feed largely on vege- 

 tation. 



The families containing aquatic species are Amphizoidai, 

 Haliplidai, Dytiscidas, Gyrinida3, Hydrophilidie, Parnidte and 

 Dascyllida3. The great majority of individuals and species 



