241 

 Denning: Trichoptera 



are strongly attracted to lights, especially to blue 

 neon lights. Yellow and red lights are usually the 

 least attractive. Conventional type light traps will 

 yield large numbers, especially if placed near a 

 productive source of water. If electricity is not avail- 

 able, automobile lights, gasoline lanterns, or a 

 portable mercury glow-tube light may be used to 

 advantage. 



Adult caddisflies should always be preserved in 

 70 to 80 per cent alcohol. The only exceptions are 

 Leptocella — slender, white species, which should 

 be kept dry. 



Larvae and pupae. — Immature stages of Trichoptera 

 are collected by turning over stones, logs, and other 

 objects in the water. In streams many larvae wedge 

 themselves into narrow crevices under stones; a few 

 species live exposed on sand or gravel, and some 

 burrow beneath the surface. In lakes or ponds, espe- 

 cially if marshy, larvae often are found around emer- 

 gent plants. Drift, weeds, or debris often contain 

 larvae. In general, caddis larvae are restricted to 

 particular habitats, each species showing a preference 

 for certain types of water and kinds of bottom. Pupa- 

 tion usually takes place in the larval case, or in 

 pupal cells fastened to rocks (fig. 10:2/). 



Larvae and pupae should be preserved in 70 to 80 

 per cent alcohol. Some may be removed from their 

 cases, but larval and pupal cases or pupal cocoons 

 should also be collected with their contents intact 

 because pupae can be identified if the male genitalia 

 are well developed. This makes possible the asso- 

 ciation of adults with larval cases and sometimes 

 also with sclerites of the cast larval skins. Vials 

 containing larvae and pupae, especially the larger 

 forms, should be decanted and refilled with alcohol 

 sometime after the original collection is made. This 

 is advisable because water in the cases and body 

 fluids dilutes the alcohol and permits decomposition 

 to occur. 



Key to Families 1 

 Adults 



1. Size small, not more than 6 mm. long; wings long, 

 narrowed, fringes very long, often those of hind wing 

 longer than breadth of wings; antennae shorter than 



fore wings, front tibia with only one spur 



HYDROPTILIDAE 



— Larger insects, size ranges from 5 to 40 mm.; wing 

 fringes not longer than breadth of wings; antennae 

 seldom shorter than wings 2 



2. Ocelli present 3 



— Ocelli absent 8 , 



3. Maxillary palpi 3-segmented LIMNEPHILIDAE ° 



— Maxillary palpi 4- or 5-segmented 4 



4. Maxillary palpi of males 4-segmented 



PHRYGANEIDAE 



— Maxillary palpi 5-segmented 5 



5. Maxillary palpi with 5th segment 2-3 times length 

 of 4th segment (fig. 10:4<z) PHILOPOTAMIDAE 



— Maxillary palpi with 5th segment only slightly longer 

 than 4th segment (fig. 10:46) 6 



6. First 2 segments of maxillary palpi short, thick, sub- 

 equal (fig. 10:46) RHYACOPHIL1DAE 



'Adapted from Ross (1944). 



i k 



Fig. 10:4. Generic characters of Trichoptera. a,b, maxillary 



palpus; c-i and k, dorsal view of adult pronotum and mesonotum; 



/, tarsus; a, Wormaldia; b, Ryacophila; c, Psychomyia; d, Seri- 



costoma; e, Brachycentrus; f, Beraea; g, Hydropsycbe; h, 



* Helicopsyche; i, Goera; /', Beraea; k, Ganonema (Ross, 1944). 



— Second segment of maxillary palpi much longer than 

 first 7 



7. Anterior tibiae with 1 spur, middle tibiae with 2 or 3 

 spurs LIMNEPHILIDAE 



— Anterior tibiae with 2 or more spurs, middle tibiae 

 with 4 spurs PHRYGANEIDAE 



8. Maxillary palpi with 5 or more segments 9 



— Maxillary palpi with less than 5 segments 11 



