706 



CLASS IV. INSECTA. 



torpid. After some weeks they change into motionless pupae 

 with free limbs. Boreus is devoid of pro-legs in the larval 

 stage, and of wings in the adult. Bittacus resembles a Daddy- 

 long-legs and has very long limbs. 



Fam. 1. Panorpidae. With the characters of the Order. Panorpa, 

 Bittacus, Boreus. 



Order 17. TRICHOPTERA.* 



Body and wings covered with fine hairs ; the latter with few 

 nervures arising from one another at very acute angles ; hind-wings 

 larger than fore-wings with a well marked anal area ; antennae, 

 thread-like ; mandibles absent. Larvae caterpillar-like ; they 

 usually construct a case to live in. Pupa like an immature 

 imago and active just before the last ecdysis. 



The Caddis-flies have their two pairs of maxillae united to 

 form a sucking tube. The meso-thorax is bulky : the large 

 coxae of the anterior legs arise close together. There are nine 

 distinct abdominal segments and the last bears a pair of pincers 



in the male. The moth- 

 like images are weak on 

 the wing and haunt the 

 shady margins of the 

 streams from which they 

 emerge. Mandibles, 

 though absent or obsolete 

 in the imago, are present 

 in the pupae as well as 

 the larvae. The eggs are 

 laid, in jelly-like clumps 

 of a hundred or so, in the 

 water. The newly hatched larvae at once set about building the 

 well known caddis-worm cases, from which they protrude only 

 the head and thorax, a strong pair of hooks at the end of the 

 body serving to anchor the larva in its case. The larvae breathe 

 by abdominal tracheal gills ; they live many months and in some 

 cases through the winter ; they are largely vegetarians but 

 at times eat other insects. During the period of pupation the 



* McLachlan, Tr. Ent. Soc. London (3), v, 1865, and Monographic 

 Revision of the European Trichoptera, 1874-80. Lucas, Arch. Naturg. 

 lix, p. 285, 1893. 



FiG. 453. Phryganea striuta. 



