230 [March, 



"Wherever there is fresh water, either Btanding or running (so 

 long as it be not habitually dried up by the heat of summer, or 

 poisoned by the refuse of mines and factories, or the sewage of large 

 cities), there caddis-flies will be found. But the immediate vicinity 

 of water is not absolutely necessary, for many of the more powerfully 

 organised species evidently take long nocturnal flights, and are often 

 dislodged during the day in localities very far from water. I remember 

 once finding numbers of a species of Limnopliilus in a sheltered hollow 

 on the summit of a bare chalk-cliff, where there was no fresh-water 

 for two or three miles. I have several times before had occasion to 

 refer to fir-trees as particularly productive to the Neuropterist ; to 

 the collector of Triclioptera they are pre-eminently favourable. The 

 best way is to beat the branches over the net, and the caddis-flies 

 that tumble into it must be boxed or bottled speedily, for they are 

 wonderfully nimble, and by their peculiar zig-zag motions, often 

 escape ; and this habit renders their pursuit when on the wing some- 

 what perplexing, for although they do not fly far when disturbed, 

 they often bafile the collector, and are even difHcult to detect when 

 settled, though probably under one's very nose. Some species (e. g., 

 Colpotaulius) may be " trodden out " from the herbage on the margins 

 of ponds, and the longer the same spot is disturbed, the more abundant 

 the insects become. Another good plan is to separate the reeds or flags 

 with the hand, and examine closely near the roots or at the surface of 

 the water, for this is the favourite diurnal hiding-place of many. The 

 copings of bridges and walls should not be neglected. I have, on 

 more than one occasion, found good species under the coping of the 

 bridge over the Serpentine in Hyde Park. Some species of the 

 beautiful long-horned IjeptocerxdcB fly briskly in the hot sunshine close 

 to the water in calm weather ; but, if an air of wind disturb the sur- 

 face, or the sun become obscured for a moment by a passing cloud, 

 they mount rapidly into the air and disappear. Some again (species 

 of Hydrops]] die for instance) dance in swarms over streams, esj^ecially 

 towards dusk. Although (with only one or two exceptions) they are 

 all aquatic in their earlier stages, yet their habits are as varied as are 

 those of the terrestrial Lepidoptera. Many genera can only exist as 

 larvfe in water that is always in a placid condition (such as that of 

 ponds), whereas others require the element to be highly aerated (e. g., 

 Wiyacopliila) and constantly cold, and there are lovers of every inter- 

 mediate state, so that a few miles walk along the banks of a small 

 stream sufiiciently varied in its character, will furnish a large number 

 of species. Even the mechanical contrivances by which man alters 



