SPONGILLA-FLIES — PARFIN AND GURNEY 

 Table 5. — Records of predators attacking Sisyridae 



445 



of S. fuscata larvae on a sponge colony is small in stagnant waters; 

 however, in the Susaa River, Denmark, on a portion of a colony 

 "only half as large as a hand," he found 25 larvae, and concluded 

 that there were undoubtedly several hundred on the whole colony. 



Navas (1935, pp. 76-78) has given a fragmentary list of a few sponges 

 .found in certain countries, but he has not correlated most of them 

 I with species of Sisyridae. Lestage (1921, p. 340) has stated that 

 ithe larvae occur as parasites upon filamentous algae and bryozoans 

 such as Cristatella mucedo in addition to the sponges. Wesenberg- 

 sLund (1939, p. 385) mentioned that Sisyra larvae are often found on 

 Cristatella. However, Brown (1952, p. 158) pointed out that third- 

 instar Climacia larvae have been found upon algae-covered rocks and 

 ;beneath bare rocks, but that they were not feeding. The fully 

 .grown third-instar larva leaves its host sponge and may wander 

 about or hide in protected places dm-ing its last day in the water, 

 and usually does not leave the water to look for a pupation site until 

 evening. Consequently, he concluded that it is possible that such 

 migrating or resting larvae, found upon algae or bryozoans, might have 

 been the basis of Lestage's statement. 



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