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(Wollaston Catalogue 1857.) (with 482 sp)

Genera with 4 sp & up.

sp. with vars [calculation not transcribed]

Genera with 3 & down [calculation not transcribed]

Proportion of vars to sp. [calculation not transcribed]

Wollaston old Book: with nat. sp

sp 229 sp with vars [calculation not transcribed]

 

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Mr Wollaston having worked out the Coleoptera of the Madeira group with extraordinary care, & as he has marked the varieties with Greek letters, I have thought it desirable to see how the rule held in this one instance with insects. There are altogether 213 genera with 482 species - Of these genera 46 (including 198 species) have one or more species presenting one or more varieties, & these genera have on average 4.26 species: whereas the remaining (167) genera (with 284 species) have on average only 1.70 species per genus.

The Cat. for 1857 has marked the certainty & probably naturalised insects with 1 or 2 asterisks. These omitted in my table 100 sp. added & few vars changed into species & reverse.

(On Commonness of Variable species)

Mr W. p XII. enumerates 9 sp. as individually most of common & told me of 2 others Oxyletis & Ptinus making 13 species. Hence 13/482 = 1/37 total by new Catalog are very common. But of the 61 sp. which have vars, - 6 are very common - equal to about 1/10th.

N. B. Commonness evidently gives chance of variations; but it hardly accounts for prevention of varieties

[calculation not transcribed]