XIV CONTENTS. 



Introduced by Shakspeare and Hogg. Theories respecting 

 its emission. Is found at all seasons. Verses suggested 

 by its appearance when covered with hoar-frost page 207 



LETTER XII. 



CONCLUDIXG EPISTLE. 



Notices of some insects not mentioned by Shakspeare. The 

 Ichneumonidaj ; their oviposition and imjjortance. Dragon- 

 flies. Their rapacious habits. Poetical notice of them as 

 Damsel flies. Attracted by peculiar colours. Habitats of 

 two species mentioned. Number of lenses in the eye. 

 Mask of the larva. Descent of the parent fly into the 

 water, when about to deposit her eggs. Analogous fact 

 observed in a species of Phryganea. Caddis-worms. 

 Variety of material employed in the structure of their 

 cases. Shells thus employed. Ingenious defence ; sul)- 

 stitute for the usual grating. The great water-beetle 

 {Dyticm marginalis). Its flight, and its food. The water- 

 scorjiion {Nepa cinerea). The boat-fly {Notonecta glmica). 

 Ilydrometridfe. Entomology makes every pool of water 

 attractive. Appearance of insects at irregular intervals. 

 One example of tliis furnished by a moth {Plusia feshicts). 

 Numbers of a gnat {Chironomus virescens), in 1832. Of 

 the cockchafer {Melolontha vulgaris) in 1835. Its ravages 

 in 1688. Failure of parsley in 1830-31 ; its growtli in 

 1832. Recognition of certain insects in unexpected 

 situations. Examples — Pentatoma riifpen in Belfast ; 

 Cossonus Tarda at Cranmore ; a burying beetle (Nfcro- 

 phorus morhwrum) on a high mountain. Mutual dei)cn(l- 

 ence of the sciences on each other. Conclusion . 225 



