4 ENTOMOLOGICAL NEWS. [Jan., '04 



The Colossal Silk-worm Moths of the Genera 

 Attacus and Rothschildia. 



BY ALPHEUS S. PACKARD. 



The word colossal is used advisedly in speaking of these 

 moths, for they are mammoths compared with the most primi- 

 tive Lepidoptera, such as Eryocephala and Microptcryx, which 

 are no larger than small-sized caddis-flies. 



The species of Attacus comprise the largest in size and ex- 

 panse of wings of all the Lepidoptera, although the bulk of 

 the body is exceeded by some Sphingidae. The lamented Mr. 

 Grote had justly separated the American species, before that 

 referred to Attacus, under the name Rothschildia from A. 

 atlas. Our own studies both as to the larval and adult 

 characters had also led us to regard the American Attaci as 

 belonging to a distinct genus, and we had given a ms. name 

 to the group. In their venation and the antennae as well as 

 other characters the species of Rothschildia, which among 

 Lepidoptera are typically neogsean, not occurring in Africa or 

 Asia, present constant differences from Attacus. There are 

 also noticeable differences in the markings, Attacus alias and 

 its congeners presenting constant differences. 



The presence of a lanceolate oval clear spot in the last sub- 

 costal cell shows that Attacus is more specialized than Roths- 

 childia. The ocellus present near the apex of the forewings of 

 Rothschildia is wanting in the species of Attacus, its place 

 being taken by a deep indian red slash, ending in a fine line 

 passing to the outer edge of the wing. 



As regards the larval characters of the two genera in all 

 their stages we now have very fair material. We are indebted 

 to M. G. Poujade for excellent figures of the larva of Attacus 

 atlas, (Annales. Soc. Ent. France, 1880, PI. 8). I have, with 

 the aid of Mr. L. H. Joutel, reared the larva of, and have 

 colored drawings of RotliscJiildia oriiaba, /\. jonilla (duct us}, 

 and in the American Museum of Natural History is a series 

 showing the three stages of A', jacobcie from Buenos Aires. 

 Burmeister has also given good colored drawings of the cater- 

 pillar of A', hcspct'us, cthra, aurota , bet is, and spcculifcr. 



