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Show 118 MR. A. BOUCARD ON THE GENUS PLUSIOTIS. [Mar. 2, The genus forms the passage between Pelidnota and Chrysina, and consists of a number of species of a splendid metallic colour. They are exclusively American. One species, P. Iceta of Sturm (amalia of Burmeister), is said to be from Valparaiso ; but I think the locality is doubtful, inasmuch as, from the descriptions of these authors, it seems to be only a variety of P. adelaida. All the other species are from Texas, Mexico, Guatemala, Costa Rica, and Panama; but very likely several species of this fine group may yet be met with in Columbia and Ecuador. Having acquired lately three magnificent new species of this genus, one of which, P. aurora, has been in m y private collection for two years past, I have considered the present moment very favourable for describing these new species, and at the same time drawing up a monographic list of all those previously described. The species are excessively rare in collections, being found only occasionally in the countries they inhabit. When travelling in the State of Oaxaca (Mexico) from 1857 to 1861, I discovered the two fine species P. adelaida and P. victo-rina. In April 1858 I had the good fortune to discover the splendid Chrysina adolphi, Chevr., in the neighbourhood of Tuquila, and on the 18th of May of the same year a fine new species of Plusiotis, which I call lacordairei. Although seventeen years have elapsed since its discovery, the species is still undescribed and has never been found by any other traveller. These beautiful insects, although so brilliant in colour, are not easily found, because they pass the day, like the common European Melolontha vulgaris, devouring the leaves of trees, and are very difficult to be perceived among the foliage. A little before sunset they fly about; and I have procured several specimens of P. adelaida attracted towards m e by tbe light of a fire. I have found P. victorina and P. lacordairei on tbe leaves of oaks, which they were devouring. I have also found in the same manner Chrysina adolphi and its variety C. mnizechii. It is therefore on these trees that they must be searched for. Being assimilated in colour to the foliage, they are very difficult of detection where present; and this must be one of the principal reasons why they are so seldom sent home by collectors. The majority of those I have seen in collections were found dead on the road, and are consequently imperfect specimens. By shaking young oaks, I have procured some specimens of P. lacordairei. To be successful in finding these insects it requires to be at the proper place in the proper season, as they are very local species and live only a short time. The spring is the best time of the year to search for them. It is also necessary to have great patience, looking carefully in all directions on the oaks, principally on young trees when the leaves are coming out. The following list comprehends all the species of this rare and beautiful genus. |