CHAPTER 9 



Aquatic Neuroptera 



By H. P. Chandler 



California Department of Fish and Game 





Family SISYRIDAE 

 Spong il la-F I ies 



The only strictly aquatic family of Neuroptera is the 

 Sisyridae. Its larvae occur as parasites on fresh-water 

 sponges belonging to the family Spongillidae. They 

 creep about in and on the sponge, inserting their 

 styletlike mouth parts into the living cells for nourish- 

 ment. When mature they emerge from the water and 

 pupate in a double-walled cocoon. The adults are 

 known as spongilla-flies. They are small typical 

 neuropterans with large eyes, long filamentous anten- 

 nae, and large membranous brown or spotted wings 

 folded rooflike over the body. 



Relationships. — This family is regarded as most 

 closely related to the Osmylidae, which have semi- 

 aquatic larvae and are found throughout most of the 

 world except North America. The larvae of Osmylidae 

 do not have gills but hide in moist places near the 

 margins of streams and feed upon dipterous larvae. 

 The adult Sisyridae differ from the Osmylidae in that 

 the cross veins are fewer and unbranched, the larvae 

 have gills, the one-segmented tarsi are single clawed, 

 and the styletlike mandibles and maxillae are curved 

 downward. The family consists of six genera and 

 about thirty-two species distributed throughout the 

 world. Only two genera, Sisyra Burm. 1839 and Cli- 

 macia McLach. 1869, are known from North America. 



Respiration. — Respiration of the second and third 

 larval instars takes place by means of ventral jointed 

 tracheal appendages, folded medially and invisible 

 from above, on abdominal segments one to seven. 

 These gill appendages are vibrated rapidly, creating 

 a current across the gill surfaces which aids in 

 respiration. Since they are not present in the first 

 instar, they are not believed to be remnants of the 

 abdominal appendages found in primitive insects. 

 Apparently respiration is cuticular in the first instar. 



Life history. — The eggs are oval with a micropylar 

 knob at one end. They are usually placed in a crevice 

 or depression on some object overhanging the water 

 such as a branch, rock, pier, or bridge. Two to five 



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eggs are covered by a blanket composed of silken 

 threads applied in a Z-pattern by spinnerets situated 

 at the end of the ninth sternite. Hatching occurs in 

 about eight days. The larva escapes from the egg by 

 means of an egg-burster situated on the tip of the 

 amnionic membrane which it soon sheds. It then 

 drops upon the surface of the water and, often with 

 considerable difficulty, forces its way through the 

 surface film. It may crawl on the under side of the 



1 rr I 



Fig. 9:1. Third instar larva of Climacia (Brown, 1952). 



