Acentropus. 147 



by some of our entomologists -,"* I presume this refers 

 to English cabinets, at all events it is true that most of 

 the English specimens have the middle segments of the 

 abdomen darker than the rest, but I feel confident that no 

 one who examines a series of Acentropus would think of 

 resting a new species upon that alone. The value, how- 

 ever, of Newman^s note is, that he recognizes the Neva 

 insect as an English species, and the one most commonly- 

 seen in our Cabinets. Hagen had previously told us 

 (Stett. Zeit. 1859, p. 203) that specimens from England 

 were identical with one of Kolenati's specimens from St. 

 Petersburg which was sent to him, and that Kolenati's 

 doubt on the subject was unfounded. Lastly, Heinemann 

 cites Stainton's insect and Kolenati's insect as identical 

 with what he calls A. niveus ; and Snellen (Tijd. voor 

 Eut. 1871, p. 170) considers that the Dutch specimens 

 agree perfectly with English examples, and with those 

 collected by Nolcken in the Neva, and that the whole 

 are referable to one and the same species. 



Of A. Nevce Nolcken says " female unknown," and 

 this is true. But Kolenati says, " I saw one female dive 

 and crawl down the stem of the Potaniogeton." Now this 

 was in 1846, ten years after Stephens in his 'Illustra- 

 tions ' had given the winged Hansoni as the female of 

 niveus, and eight years before the existence of an apterous 

 female was dreamt of. Under these circumstances, I 

 think we may fairly infer that the female which Kolenati 

 saw was a winged female : had it been apterous, so startling 

 a novelty would scarcely have been unnoticed. Even 

 when writing his account of the insect (which was not 

 published till 1858), Kolenati would seem to have been 

 unaware of Curtis and Dale's discovery of the apterous 

 female in 1854, and the record thereof in our 'Proceed- 

 ings' may well have escaped his notice ; whilst Brown's 

 history of the genus was not given to the public until 

 1863, and then in the form of an Appendix to a local 

 Natural History, so that it was scarcely likely to attain 

 that extended circulation on the Continent which the 

 interest attaching to its contents rendered so desirable. 



* For instance, by Newman himself : "it is curious that the basal seg- 

 ments of Acentria nivea become greasy very shortly after the insect has 

 been shut up in a camphored drawer" (Zool. 5629). I apprehend that 

 the beautiful belt is Olivier's "partie superieure de I'abdomeu un peu 

 obscure." 



