2\6 VARIETIES. 



strata, form a good idea of the insects most likely to occur in 

 any district. 



Perhaps you or some of your correspondents may also be 

 able to inform me the cause of the difference which in different 

 years is observable in the brightness of colour and size of in- 

 sects of the same species ; most must have noticed how^ much 

 finer and more beautiful butterflies are some summers than in 

 others, — can this be at all owing to the nature of their food 

 when in the caterpillar state? As the wet or drought of 

 various seasons so much affects vegetation, bringing plants to 

 perfection or stunting their growth, it may perhaps render them 

 more or less nutritious to the insect tribes to which they afford 

 sustenance. It is supposed, and perhaps with reason, that the 

 nature of their food exerts a decided influence on the colour 

 and size of the higher animals ; — why may it not affect in the 

 same way creatures so much more frailly-formed ? 



Any information in a future number on these subjects, which 

 are probably well understood by the initiated in your pleasing 

 science, would, I believe, be interesting to many of your readers 

 besides myself. 



And oblige yours, &c. Y. 



Ludlow, Nov. 10, 1832. 



23. Ignis Fatuus. — '* This appearance has been strongly surmised 

 to be a luminous insect. It is many years since the similarity of its 

 motion was observed to that of an insect avoiding pursuit. A sub- 

 sequent examiner has stated, that he approached one near enough to 

 see distinctly the form of an insect, with wings like a dragon fly. 

 Two or three years ago, an anonymous article in a country paper 

 announced, that some person, in digging up the mud of an old pond, 

 had discovered two creatures, which he surmised to be the insects in 

 question, and which he described as looking like cray-fish with 

 wings. The Entomologist, who can ascertain the fact, by securing 

 an Ignis Fatuus in a bottle, will have drawn a tooth from the jaws of 

 superstition and human suffering." — From the Westminster Review 

 for October, 1832. 



We shall feel much obliged by any information our corre- 

 spondents may be able to furnish us with on this subject. Is 

 the insect in question the mole-cricket ? Our readers will bear 

 in mind that we want facts only ; we have theories on the sub- 

 ject in abundance. — Ed. 



