540 PROCEEDINGS OF THE ACADEMY OF [Oct., 



The species occurs in the Alnus association a short distance east 

 of Round Pond, in company with Tipula dejecta Walker, the only 

 other crane-fly on the wing at this date and hour. 



The water is stagnant or nearly so with the little pools filled with 

 an algal growth, kindly determined for me by Dr. J. R. Schramm, of 

 Cornell University, as being near Microspora and Tribonema, abun- 

 dant; (Edegonium sp. and Spirogyra sp., the latter conjugating 

 laterally, and some Mougeotia, Vaucheria, etc., with many Diatoms; 

 in addition to these there is a dense growth of young seedlings 

 of Impatiens hi flora. The mud is so soft that it is necessary to 

 wade knee-deep in order to explore this region. There is still ice 

 down underneath the stratum and the Alnus is just coming into leaf, 

 allowing the sun to light up the ground underneath. The dominant 

 herbaceous plants at this time were Carex aquatilis, Saxifraga pennsyl- 

 vanica, with the plants in bud and the stalks not more than six to 

 nine inches high, and Caltha palustris in full flower. 



There is no doubt but that the Tipula and the present species both 

 emerged from the stagnant pools formed in the marsh adjoining- 

 Grassy Creek. Both species of crane-flies were common, but the 

 Tipula was more in evidence by its larger size and habit of flying. 

 The Tricyphona was usually found resting on the saxifrage or on the 

 inclined side of alder limbs, the males often fluttering about from 

 place to place a short distance above the ground, never very rapidly. 

 The females were found resting on the alder stems, inactive, and the 

 males were presumably searching for them. 



In the afternoon when the warmth of the sun made itself felt, 

 none of the Tricyphona and only a few of the Tipula were in evidence 

 in this haunt, their places having been taken by dense swarms of 

 Chironomiclae and a very few of the crane-fly, Erioptera septemtrionis 

 Osten Sacken. 



On May 20, Mr. P. A. Claassen found a male and a female in his 

 tent-traps set near this place, proving that the immature stages are 

 spent in the mud beneath. 



RHAPHIDOLABIS Osten Sacken. 



Rhaphidolabis Osten Sacken; Monographs of the Diptera of North America, 

 pt, 4, p. 284 (1869). 



Subgenus RHAPHIDOLABINA subgen. n. 



Similar to Rhaphidolabis s. s., differing as follows: Antennae 

 15-segmented, the first eight segments of the flagellum normal, 

 cylindrical, bearing strong hairs at about midlength, these alternating 



