38 U.S. NATIONAL MUSEUM BULLETIN 256 



Larvae with dark blue bands, found at Mazatlan on the west coast 

 of Mexico. 



Larvae similar in color and habits to . junctolineella, found on the 

 coastal strip of southern California. 



Larvae pale-colored, resembling those of 0. subumbrella, occurring 

 in the drier sections of southern California. The entrance hole is closed 

 and the frass not discharged. Heinrich includes California in the 

 distribution of subumbrella. 



Olycella junctoUneella (Hulst) 



The distribution embraces the coastal and subcoastal portions of Texas, 

 and the northeastern Mexican States of Coahuila, Nuevo Leon, and 

 Tamaulipas. In Texas it occurs from Brownsville along the gulf coast 

 as far north as Galveston, thence inland as far west as Presidio in the 

 Big Bend country of the Rio Grande; it has not been found north of 

 San Antonio nor on the western plateau. In Mexico its range extends 

 southward at least as far as Tampico; it is common around Victoria 

 in Tamaulipas, but does not seem to occur on the Central Plateau. 



The insect is comparatively abundant. The usual food plant is the 

 shrub pear Opuntia lindheimeri, which is the dominant and often the 

 only prickly pear growing throughout a great part of its range of dis- 

 tribution. On the Texas coast 0. inermis is freely attacked, as well as 

 the dwarf pears 0. Juscoatra, 0. grandiflora, 0. macrorhiza, and others of 

 the 0. tortispina group. In the Mexican State of Coahuila larvae have 

 been found in the low-growing 0. microdasys, while at Presidio in 

 Texas tlie related but much larger 0. rufida is the host plant. In Australia 

 the larvae have bred successfully in 0. inermis and 0. stricta and in the 

 younger segments of the tree pear 0. streptacantha. 



The adult possesses grey forewings with indefinite transverse mark- 

 ings; the hind wings are light grey in the female, white in the male. 

 There are two generations annually, but pupation and emergence are 

 extended over a considerable period. In Texas, moths from the winter 

 generation larvae emerge from mid-January to May, the earliest 

 recorded date being January 18, while those of the summer generation 

 appear from late August to early November. Full-grown larvae, young 

 larvae, and unhatched eggs may occur simultaneously in the same field 

 in certain months, e.g., March and October. 



The eggsticks contain from 4 or 5 to as many as 30 eggs, the usual 

 number being 10 to 12. They are generally attached to the spines or 

 fine spicules of the fruit and young growth. The incubation period 

 occupies 7 to 14 days according to the time of the year. The females 

 are ratlier prolific and often produce more than 200 eggs per individual, 



