42 THE ENTOMOLOGIST. 



Platysamia cecropia {Attacus cecropia, Linn.). Platysamia is 

 the generic name given to this species and the three following 

 ones, which are all closely-allied species. P. cecropia is the 

 largest silk-producer in the United States. The cocoon, open 

 like those of the same genus, is surrounded by a large irregular 

 envelope, which is often of an extraordinary size. The larva has 

 six stages (some authors say it has but five) ; is more difficult to 

 rear in the open air in northern countries than T. polypheimis. 

 It feeds on a great number of fruit and other trees, especially 

 wild plum, willow, &c. The moths pair easily in captivity. 

 Brodie, in ' Papilio,' February, 1883, gives a list of forty-nine 

 species of plants belonging to the following genera : — THia, 

 Acer, Pimnus, Spircea, Cratcegus, Ptjrus, Amelanchier, Ribes, 

 Samhuciis, Ulmus, Quercus, Fufius, Conjlus, Carpinus, Betula, 

 Alnus, Salir, and Popidiis. Other authors give the following 

 genera : — Berheris, Liriodendron, Syringa, Carya, Gleditschia, 

 Ruhus, Ceanotliiis, Ampelopsis, Ceplialanthus,Fraxinus, Vaccinium, 

 and Rosa. 



Platysamia ceanothi, Behr {calif ornica, Gr.). A species 

 smaller than P. cecropia. The envelope, which is iron-grey and 

 pyriform, is much larger in proportion than the true cocoon 

 inside, the space between the two being rather considerable. 

 The larva of this species has been reared in Europe on plum 

 and willow. Probably it would live on several of the same 

 food-plants as P. cecropia and P. gloveri. The name of ceanothi 

 is derived from one of its principal food-plants, Ceanothus ameri- 

 canus. The larva, as well as that of P. gloveri, is very similar to 

 that of P. cecropia, especially in the first two stages. From the 

 third stage the difference, the most striking, is that the dorsal 

 tubercles of ceanothi and gloveri are of a uniform colour, orange- 

 red or yellow, whilst the first four tubercles on the back of the 

 cecropia larva are red, and the others yellow. The lateral 

 tubercles are blue on the three species. The ceanothi moths 

 have the background of the fore wings of a reddish brown ; on 

 the contrary, the colours vary in the other two species. The 

 moths do not pair so easily as those of cecropia. 



Platysamia gloveri, Streeker. A species which is inter- 

 mediate between P. cecropia and P. ceanothi in size and colouring 

 of the wings. The envelope of the cocoon is silvery grey ; the 

 true cocoon is dark brown. The outer envelope adheres to the 

 cocoon, leaving no space between the two. This species was 

 discovered in Utah, where cocoons were found on a small leaf 

 sallow. It is also found in Arizona. 



P. cecropia, P. ceanothi, and P. gloveri, being closely-allied 

 species, pair readily among themselves, and very interesting 

 hybrids have been obtained by the crossing of cecropia with 

 ceanothi and cecropia and gloveri. 



Platysamia Columbia, Smitb. This species, somewhat 



