122 U.S. NATIONAL MUSEUM BULLETIN 256 



emerged, had penetrated into the segments to which the fruit was 

 attached, and not infrequently had advanced through these segments 

 into the penultimate cladodes. 



CECIDOMYIA Meigen 

 Cecidomyia opuntiae (Felt) 



This midge was described in 1910 from material reared from prickly 

 pear segments growing in the New York Botanical Gardens. It was 

 still breeding in the greenhouses of the Gardens in 1924, but no more 

 recent information is available. Although the original infestation was 

 probably introduced with Opuntia plants from some part of America, 

 the insect has not been recorded from the field. The larvae live in cells 

 beneath the areoles. 



In September 1921 infested segments of several species of prickly pear, 

 including 0. dillenii, 0. lindheimeri, 0. robusta, and 0. elatior, were re- 

 ceived at Uvalde, Texas, from the New York Botanical Gardens. 

 Adults emerged in October, but efforts to secure oviposition in prickly 

 pear segments in cages were unsuccessful. 



MAYETIOLA Keiffer 

 Mayetiola KeiflFer, species A 



This insect would appear to be very rare or to have a local distribution. 

 The two records of its occurrence were made in the neighbourhood of 

 Floresville, Wilson county, Texas. In August 1 924 the orange-colored 

 larvae were numerous in cells in segments of Opuntia lindheimeri in one 

 small area; the affected segments bore a yellow appearance. Several 

 of the infested cladodes had been produced by fruit attacked by 

 Asphondylia. No adults were reared. 



In February 1928 apical segments on a plant of 0. fuscoatra near 

 Floresville were infested with midge larvae living in cells beneath 

 the areoles, which were swollen and yellow. The small adults emerged 

 in March and were identified by C. T. Greene of the U.S. Bureau of 

 Entomology as an undescribed species of the genus {Phytophaga Ron- 

 dani = ) Mayetiola. 



Mayetiola KeiflFer, species B 



This is another form that has been identified as an undescribed species. 

 The two records of its occurrence were made at Cuernavaca, State 

 of Morelos, Mexico. In April 1926 a yellowed segment of the tree 

 pear Opuntia tomentosa contained between 100 and 200 small orange 

 larvae; adults were not reared. In March 1928 two segments of 0. 



