16 Lake Maxinkuckee, Physical and Biological Survey 



water. They may often be taken pairing in such places, and pre- 

 fer to lay their eggs in the shallow water along shore, amongst the 

 yellow algae, where the water is scarcely deep enough to cover them. 

 They feed largely on Diptera. 



Found at Lost Lake, Lake Maxinkuckee, Twin Lakes, Yellow 

 River, and Tippecanoe River. 



11. PACHYDIPLAX LONGIPENNIS (Burmeister) 



A very cosmopolitan species found over the whole United 

 States, Mexico, and the Bahama Islands. Both sexes are swift 

 fliers, and as the males, which are most in evidence, hover near the 

 surface of the water and in among the vegetation they are difficult 

 to catch. The females remain at some distance from the water 

 when not ovipositing, and so are less difficult to capture. When 

 ovipositing both sexes fly in and out among the cow-lilies and 

 arrowheads where it is hard to strike with a net, and when they 

 do alight it is usually on the sides of the lily stems close to the 

 water. This species has the curious habit of drooping its wings 

 and elevating its abdomen when resting, so that the insect ap- 

 pears to be trying to stand on its head. As Williamson remarks, 

 this simply furnishes the large Libellulas an excellent mark to nip 

 at, and the author has repeatedly seen L. luctuosa and L. pulchella 

 snap at the tip of the elevated abdomen and drive the Pachydiplax 

 away, but has never seen one of the latter killed. 



This species was found during the entire summer in every lo- 

 cality visited. 



12. LIBELLULA LUCTUOSA Burmeister 



This was the most abundant of all the dragon-flies, and was 

 found on all the lakes visited. It seems to prefer the higher and 

 drier ground and was not usually found near low and swampy places. 

 It is a strong flier and often pauses and holds itself stationary by 

 rapid vibration of its wings. 



It is also inquisitive, searching into everything, and often re- 

 turning to the same place when missed by the net. When fishing, 

 the author has repeatedly seen them snap at the cork float on the 

 fishing line, both while it was in the air during the casting and 

 while it was floating on the surface of the water. 



When alighting they often prefer the side of a rush stem, or 

 even the bare ground. The eggs are deposited in the shallow 

 water near the shore, the female hovering over the spot and re- 

 peatedly dipping her abdomen beneath the surface in almost the 

 same place. The black markings of the wings make this species 

 very conspicuous, especially in the male where they are contrasted 



