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. leta 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 my 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 Jacordairei. 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 diffi- 
cult to be perceived among the foliage. 
A little before sunset they fly about; and I have procured several 
specimens of P. adelaida attracted towards me by the light of a fire. 
I have found P. victorina and P. lacordairei on the 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. 
lacordairet. 
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. 
