34 



PRINCIPAL CACTUS INSECTS OF UNITED STATES. 



As has been stated, this is an important enemy of the Opuntia 

 plant where the fruits are desired for food. In cactus plantations, 

 however, where the plants are reproduced by cuttings, it is of com- 

 paratively little importance. On account of its gregarious habits 

 and its location on the parts of the plant easily reached by a gasoline 

 torch, its control is not a difficult matter. 



There are three other species of Narnia which feed upon the fruit 

 of Opuntia and related plants. After pattidicomig, the most com- 

 mon species is fem-orata, which is as widely distributed in Texas as 

 that species and extends its range as far westward as Los Angeles, 

 Cal. It has also been taken in Mexico at Aguascalientes, Victoria, 



and Durango. In general appear- 

 ance it resembles pallidicomis very 

 closely, but is somewhat larger. N. 

 pallidicomis has the dilation of 

 the hind tibia narrower, lanceolate 

 shaped, and the inner part of the 

 dilation broadest behind the middle. 

 The remaining species of the 

 genus which we have observed on 

 cactus are inornata and snowi. The 

 former has been taken in California 

 and Mexico only, while we have only 

 a single record of the latter species, 

 at Albuquerque, X. Mex., in April. 



Asphondylia opuntise Felt. 1 



Asphondylia opuntuc Felt ranks 

 next in importance to the Xarnia 

 bugs so far as injury to the fruits 

 of Opuntia is concerned. It is not 

 restricted, however, to the fruits, 

 but sometimes infests the margins 

 of the joints. Its presence is first detected by a yellowish coloration 

 of the fruit or joint and later by the protruding puparia in close 

 groups of sometimes as many as 10 individuals (fig. 5). 



This species has a wide range. Specimens have been taken at many 

 points in Texas and southward to San Luis Potosi, Mex., and west- 

 ward to Los Angeles, Cal. There are evidently several generations 

 in the season, the first adults appearing in southern Texas in March. 

 Especially in California this species is extremely abundant. On 

 this account it is fortunate that its injury primarily affects the fruit 

 and does not interfere seriously with the growth of the plant. Tt 



Fig. 5. — Opuntia fruit with puparia of 

 Asphondylia opuntia. Enlarged. 

 (Original.) 



Order Diptera, Family Cecidomyiidce. 



