THE NEUROPTERA OF GUERNSEY. 157 



The Book-louse is a wingless species belonging to this 

 family. It is sometimes called the Death Watch from its 

 habit of making a ticking sound. It is very destructive to 

 collections of insects and plants. 



The Trichoptera or Caddis-flies have been ranked as 

 a separate order by some writers on Entomology ; they are, 

 however, included in the Neuroptera in a catalogue of the 

 British species published by the Entomological Society of 

 London in 1870. In the larval stage they live under water, 

 some species only in stagnant ponds and ditches, others only in 

 rapid streams. These larvae being very soft-bodied, construct 

 tubular cases of various materials, such as bits of stick, shells, 

 seeds, small stones and grains of sand, and dwell in them. 

 The perfect insects very much resemble moths, and are often 

 mistaken for them. Twenty-one species have been taken in 

 Guernsey, one of which is peculiar to the island. 



This species was first recorded in Mr. R. McLachlan's 

 splendid " Monographic revision and synopsis of the Trichop- 

 tera of the European Fauna," from which I quote the following 

 description and notes on the species : — 



" Philopotamus insidaris (n. sp.) 



" Agreeing entirely with P. Montanus in the colour of the 

 antennas, neuration of the wings, &c, and apparently without 

 the slightest difference in the anal parts of the male, but 

 differing totally in the colour and marking of the wings. 

 The anterior wings are dull pale yellow (caused by a yellow 

 pubescence on a nearly hyaline membrane) transversely 

 reticulated with greyish fuscous, and with a few larger fuscous 

 spots, whereof one at the arculus is much larger and more 

 conspicuous than the others, the costal and apical margins 

 somewhat regularly spotted with fuscous, fringes wholly 

 yellow, neuration slightly fuscescent. Posterior wings, pale 

 smoky fuscous, pterostigma conspicuously yellow, the apical 

 margin is yelloAv, festooned inwardly, fringes wholly yellow, 

 neuration fuscous. Expanse 20-25 m. m." 



" Some years ago I noticed a single female example of 

 this among a few insects collected by the late Francis Walker 

 in Guernsey. Its appearance was so remarkable as to induce 

 me to write to Mr. Luff, an entomologist resident in the 

 island, describing the insect, and he has had the kindness 

 to send me nearly thirty specimens, which do not vary in any 

 way. He says he finds the species only in one locality — 

 a small rapid stream at Saints' Bay, and that no other species 

 of the genus occurs in the island. I have not been able to 



