214 



A qua lie Organisms 



\lul/ 



2. Hemerobiidce — Of this large family of lacc-wings 

 but two small genera (in our fauna) of spongilla flics, 

 CI i mar ia and Sisyra, have aquatic larvae. The adults 

 are delicate little insects that are so secretive in habits 



and so infrequently 

 seen that they are 

 rare in collections. 

 Their larvae are com- 

 monly found in the 

 cavities of fresh water 

 sponges. They feed 

 upon the fluids in the 

 body of the sponge. 

 They are distin- 

 guished by the posses- 

 sion of long slender 

 piercing mouthparts, 

 longer than the head 

 and thorax together, 

 and by paired ab- 

 dominal respiratory filaments, that are angled at the 

 base and bent underneath the abdomen. These larvae 

 are minute in size (6 mm. long when grown) and are 

 quite unique among aquatic insect larvae in form of 

 mouthparts and in manner of life. 



The caddis-flies (order Trichoptera) are all aquatic, 

 save for a few species that live in mosses. They con- 

 stitute the largest single group of predominantly aquatic 

 insects. They abound in all fresh waters. 



The adults are hairy moth-like insects that fly to 

 lights at night, and that sit close by day, with their long 

 antennae extended forward (see fig. 1 03 on p. 1 97) . They 

 are not showy insects, yet many of them are very dainty 

 and delicately colored. They are short-lived as adults, 

 and, like the mayflies, many species swarm at the shore 

 line on summer evenings in innumerable companies. 



Fig. 121. Insect larvae. 



a, a diving-beetle larva (Coptolomus interrogatus)- 

 after Helen Williamson Lyman); b, a hellgrammite, 

 (Corydalis cornula, after Lintner); c, an orl-fly 

 larva (Sialis infumata, after Maude H. Anthony). 



