78 U.S. NATIONAL MUSEUM BULLETIN 256 



NOCTUELIA Guen^e 



This pyraustid genus of several species contains one cactus-feeding 

 representative. 



Noctuelia elautalis Grote 



This insect is primarily a flower and fruit enemy. It appears to be 

 restricted to the United States, being distributed over the greater 

 part of the plateau of Arizona, New Mexico, and West Texas. In 

 Texas its range extends eastward from the foothills around Del Rio 

 to Uvalde and along the Rio Grande to Laredo; however, it has not 

 been found north or east of Uvalde. Records of more or less heavy 

 or general infestations of larvae, made between 1924 and 1928, are 

 as follows: 



1925: Very numerous in the foothills of Valverde County west 

 of Del Rio, Texas, and around Tucson, Arizona. Present generally 

 in Arizona but not observed in western Texas and New Mexico. 



1926: Prevalent around Carlsbad, New Mexico. Fairly numerous 

 in some areas in the Tucson district. 



1927: Rather common at Eagle Pass, Texas. 



1928: Very few larvae in Valverde County, Texas. Common 

 at Mesilla Park, New Mexico. Generally prevalent in the southern 

 half of Arizona as far north as Ashfork. 



The host plants include various prickly pears of the shrub type, such as 

 Opuntialindheimeri,0.cacanapa,0.engelmannii, 0. phaeacantha, 0. atrispina, 

 0. tenuispina, and 0. macrocentra. Cylindropuntia food plants are 0. 

 fulgida commonly in Arizona, 0. imbricata occasionally in west Texas 

 and New Mexico, and one record of the small low-growing 0. stanlyi 

 in Arizona. All species of Platyopuntia occurring within the insect's 

 range of distribution appear to be subject to attack. Thus there is no 

 marked preference for a particular host. However, in Valverde County, 

 Texas, in 1925, when the larvae were very abundant in areas containing 

 a mixed flora of the low-growing 0. atrispina and both low-growing 

 and taller forms of 0. lindheimeri and 0. engelmannii, the former seemed 

 to be the most frequent host, while the taller plants of the other two 

 prickly pears were almost immune from attack. Concerning Cylindro- 

 puntias, in the Tucson district where several species are abundant, 

 0. fulgida was certainly the preferred, if not the sole, food plant among 

 this group. 



The adult has a wing expanse of about one inch; the wings are dull 

 yellowish with somewhat darker markings. The larvae are white, with 

 several narrow crimson transverse bands. 



