The Two-winged Flies 31 1 
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 pupae, 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 4 inch.) 
Fig. 421.—Pupa of midge, Chironomus sp. (From life; natural length $ 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, Eretmpptera 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 
