268 NATURAL HISTORY OF AQUATIC INSECTS CH. 



the Insect is at rest. In this position the upper wings 

 are nearly flat above, then they bend at an angle and 

 slope downwards. These two upper wings are mode- 

 rately transparent, but appear opaque when they 

 overlie the others. It is their opacity which causes 

 them to resemble Butterflies' wings, but on close 

 examination we see that they have none of the scales 

 which are characteristic of the wings of Lepidop- 

 tera [but are clothed with hairs]. The lower wings 

 are very transparent [and usually folded fan-wise] ; 

 they consist of a colourless or slightly bluish gauzy 

 membrane. The fly immediately after emergence, 

 and for some days subsequently, has a greenish tint ; 

 then it gradually turns dark. The six legs are long, 

 but the fly does not stand high above the surface on 

 which it rests. The antennae are very long, longer 

 than the body, gradually tapering, and of many 

 joints. The eyes are compound, like those of other 

 Flies and Butterflies. The mouth bears implements 

 very unlike those of the larva or pupa. There are 

 [no mandibles, but] four palps, two above and two 

 below, besides a very small proboscis [labium ? The 

 tarsi are five-jointed]." 



The esters of Caddis-flies are laid in water or on 



o o 



water-plants, or on trees overhanging a stream, or 

 sometimes far from water. 1 They are often of green 

 colour, and are laid many together in a mucilage 

 which swells out as soon as it comes in contact with 

 water, forming a cylindrical egg-rope, or in some 

 cases a flat disc. As soon as the larvae arc hatched, 



} McLachlan, Entom, Month. Mag., Vol. XVI., p. 135 (1878). 



