The Two-winged Flies 



which have a sort of sieve-like skin. In both cases the pupa breathes the 



oxygen which is mixed with water and is thus not 



compelled, as are the mosquito pupas, to come to the 



surface for air. The larvae of the genus Ceratopogon 



and its allies, which include the fiercely biting and 



blood-sucking little punkies (Fig. 422), so irritating 



to the fisherman and hunter in the north woods, 



FIG. 420. FIG. 421. 



FIG. 420. Larva of a midge, Chironomus sp. (From life: natural length J inch.) 

 FIG. 421. Pupa of midge, Chironomus sp. (From life; natural length J inch.) 



live, according to Comstock, "under the bark of decaying branches, under 

 fallen leaves, and in sap flowing from wounded trees." 



Running and half flying about over the spray- wet rocks and on the surface 

 of the smaller tide-pools between tide-lines on the ocean shore near Mon- 



FIG. 422. FIG. 423. 



FIG. 422. Mouth-parts of a female "punkie," Ceratopogon sp. lb., labrum; md., 



mandible; mx., maxilla ; mx.l., maxillary lobe; mx.p., maxillary palpus; li., labium; 



p.g., paraglossa; hyp., hypothorax. 

 FIG. 423. The tide-rock fly, Erelmoplera browni. (Natural length inch.) 



terey, California, may be seen in the winter months many small, long-legged, 

 spider-like flies (Fig. 423) whose wings are reduced to mere oar-like veinless 

 rudiments. The larvae and pupae live submerged in the salt water of the 

 outer and most exposed tide-pools, where the ocean water is held in shallow 

 depressions in the rocks, and is changed many times daily by the dashing 

 of the waves. Where the flies go when the tide is in and these rocks are 



