388 



ENTOMOLOGICAL NEWS. 



[Nov., '07 



respiratory tube, however, is strongly chitinized, the chitinous thicken- 

 ing extending on the dorsal surface to the very base. The flanks of the 

 respiratory tube bear occasional setae, and its tip is somewhat hollowed 

 to provide for the posterior spiracular openings of the trachae, two in 

 number, which traverse the tube. From the rim of the concavity at the 

 tip, proceed four small processes, each provided with a bunch of setae, 

 which serve to form the cup for holding bubbles of air, whence the larva 

 gets its supply of oxygen. An anterior pair of spiracles are borne on 

 the first segment behind the head, occurring well back in the segment. 

 They project from the dorsal surface as a pair of short cylindrical 

 tubes provided with circular terminal openings. 



The mode of life of the larva is closely connected with its 

 breathing. The larva, as was said, is found especially in wet 

 manure. If exposed to the air and deprived of the moisture 

 which it finds in its natural surroundings, it quickly becomes 

 dry and hard, and dies. On the other hand, v 

 if entirely submerged, i. e., if its air tube is \, 

 covered (the larva is unable to maintain itself 

 at the surface), it is also killed. It is therefore 

 confined, so far as ability to persist is 'concerned, 

 to a mere film of water. The necessary con- 

 ditions are evidently found in the manure beds 

 where the larv?e were so abundant. They are 

 usually found twisting and crawling about, 

 worm-like, over the straw, dragging a thin film 

 of water after them, the anal segment upraised 

 to the surface, where a bubble forms about the 

 spiracular cup. The feeding process has already 

 been mentioned. The larva does not, however, 

 feed continuously, nor is it always in motion. 

 It is often found coiled up, and hidden in the 

 material on which it lives. 



The pupa (Fig. 2) is 3.2 mm. long, the greatest width 

 being .75 mm. It resembles in general appearance other Nema- 

 tocerous pupse, especially those of the Tipulidse. 



It is at first pale in color like the larva, but upon settling down and 

 losing its motility turns dark brown. The body is largest anteriorly, 

 where the forming organs of the imago, wings, legs, eyes, etc., are 

 plainly outlined in the pupal sheaths. Nine segments are visible on the 



Fig. 2. 



