148 Annals Entomological Society of America [Vol. IX, 



This genus consists of two species found in Arizona and 

 southward into Mexico. The cocoons are very firm, those of 

 R. Orizaba being about two inches long, three-fourths of an inch 

 wide, rather ovoid in shape, usually slightly narrowed and 

 rounded at the ends, while those of R. jorulla are vase-shaped, 

 about of the same dimensions with a well defined opening 

 laterally at the cephalic end, showing the valvular arrangement 

 of loose fibers. Both species have very light grayish tan cocoons, 

 those of R. jorulla being suspended by a band of silk at the 

 cephalic end. The pupae of the two species can be separated 

 as follows: 



A. Median thoracic line distinct on all segments; caudal part of meso- 

 notum and metanotum depressed at base of wings; distal margin of wings 

 strongly elevated above the dorsal surface of body; setae on metathorax and 

 first four abdominal segments sparsely distributed, inconspicuous, orizaba. 



AA. Median thoracic line never distinct on metathorax and often indistinct on 

 mesothorax; caudal part of mesonotum and metanotum not depressed at 

 base of wings; distal margin of wings only slightly elevated above the 

 dorsal surface of the body; setse numerotis on metathorax and first four 

 al)dominal segments, con.spicuous, at least a millimeter in length, jorulla. 



Rothschildia orizaba West wood. — Color generally black 

 with light brown transverse conjunctiva, sometimes abdominal 

 segments 5-10 or 8-10 are light in color; exposed parts of 

 thorax and abdomen sparsely covered with reddish setae, less 

 than a millimeter long and almost invisible; thoracic segments, 

 face parts and appendages with indeterminate, transverse 

 striations, abdominal segments smooth; antennae of male with 

 length two and three-fourths times breadth, female with length 

 four times the breadth; face parts curving sharply to the level 

 of the labrum and maxillae; labrum variable, width about twice 

 length, usually five-sided and slightly elevated above maxillae; 

 maxillae, measured on meson, one-sixth the length of wings; 

 median line distinct on all thoracic segments; mesothorax 

 tuberculate at base of wings; caudal part of mesonotum and 

 metanotum strongly depressed adjacent to wings; the distal 

 margin of first wing always considerably elevated above the 

 dorsal surface of body ; mesothoracic spiracles slit-like ; abdom- 

 inal spiracles free, second abdominal spiracle one-half the width 

 of its margin away from the wing ; caudal end of abdomen with 

 band of stiff, straight setae, always erect. Length, abdomen 

 retracted, 23-27 mm., expanded, 30-37 mm.; girth about 

 50 mm. 



