190 Illinois State Laboratory of Natural History. 



respiratory appendages is developed into an extremely 

 long and slender breathing tube, while the other remains 

 more or less rudimentary— an interesting modification. 



The structure of the larval head [Fig. 16] separates 

 this family at once from the Tipulidae, among which it is 

 usually included. The larvae and pupae, however, as well 

 as the imago, have a tipulid hahittis and mode of life, 

 and the two families should not be widely separated. 



The larva of our American Ptychoptera is unknown. 

 The European species of the genus, according to Dr. 

 Brauer, have false feet on the 2d, 3d, and 4th abdominal 

 segments, while in Bittacomorpha they are borne on the 

 1st, 2d, and 3d. 



Bittacomorpha. 



Bittacomorpha clavipes Fabr. [Fig. 15-22.] 



Station I has previously been described — a shallow 

 swampy slough, bearing a considerable growth of wil- 

 lows, and full of rushes, Sagittaria, and swamp 

 grasses. In the exceptional spring of 1895, the river 

 was not high enough to enter this passage, and in 

 March and April it remained choked with a mat 

 of dead stems, grass, and willow leaves, through 

 which a broad stream of spring water from the 

 bank, a few inches deep, slowly worked its way towards 

 the river. 



In this mat of dead stems the Bittacomorpha larvae 

 [Fig. 15] were abundant March 17. Their cylindrical 

 form, rusty-brown color, and the absence of sutural con- 

 strictions made them look much like a decaying piece of 

 grass stem ; but they usually revealed themselves, when 

 a mass of material was being searched, by their habit 

 of coiling up when disturbed. The larvae were still 

 abundant March 28, and stomachs examined were 

 found to be filled with a solid brownish mass, largely 

 diatoms, the remainder mud and dead vegetable tissue, 

 they having evidently fed on the brownish diatomaceous 

 growth which coated the decaying stems. April 9 and 



