CACTUS-FEEDING INSECTS AND MITES 129 



Average larval period 74 



deposited by one female was 233 eggs laid in 30 separate lots at inter- 

 vals over a period of 170 days; the largest number deposited in one day 

 was 25 eggs. 



Unlike those of C. vittiger, the larvae of C. tabulata are not gregarious; 

 those hatching from one batch of eggs feed separately and soon disperse 

 over the plant. However, where the species has occurred in enormous 

 numbers in an area, hundreds of larvae have congregated on the same 

 joint. 



This species attacks Platyopuntias generally. In Texas the host plant 

 is usually Opuntia lindheimeri. In Mexico shrub pears of the 0. lindheimeri 

 and 0. cantabrigiensis group, and robust plants of the 0. sireptacantha 

 and 0. tomentosa types, are freely infested. In certain sections of Mexico 

 observations have indicated some degree of preference for shrub pears 

 in comparison with semitree and tree pears. In Australia, the shrub 

 pears 0. inermis and 0. stricta, the semitree pear 0. streptacantha, and the 

 tree pear 0. tomentosa are all subject to attack; but where the four 

 species are growing in one locality, 0. inermis is the more favoured host 

 plant. 



One note has been made of feeding on Cylindropuntias, the species 

 being 0. imhricata at San Luis Potosi. In Central America Nopalea 

 and Cereus, in addition to Opuntia, were infested. Feeding marks were 

 observed on Cactus caesius in Venezuela. Acanthocereus pentagonus and 

 Harrisia martinii has been recorded as a food plant in Australia. 



Chelinidea canyona Hamlin 



In contradistinction to C. vittiger and C. tabulata, this insect has a very 

 restricted distribution. It occurs in the higher valleys of the Frio and 

 Nueces Rivers, north of Uvalde, Texas, thence westward through the 

 foothills to the Big Bend country north of the Rio Grande, extending 

 into Mexico, San Luis Potosi, Canoas, and Ciudad Mante, according 

 to F. D. Bennett (1963, unpublished report). It is not uncommon 

 north of Uvalde, and has been found in numbers in the Chisos Moun- 



263-il7— 68 10 



