124 U.S. NATIONAL MUSEUM BULLETIN 256 



The larvae live in individual cells which are filled with dead plant 

 tissue. Their presence is conspicuous on account of the yellow or 

 brown circular patches, less than an inch in diameter, on the surface 

 of the segment. Several or many cells, each containing one larva, may 

 occur in one segment. At Tucuman the larvae pupated within the cells 

 in August, and the adults emerged in September. The insect was in 

 the pupal stage at Montevideo in December, the adults appearing 

 in the same month. 



DASIOPS Rondani 

 Dasiops saltana (Townsend) 



A Mexican form was discovered in October 1926 infesting the younger 

 segments of various kinds of prickly pears at Aguascalientes and at 

 Morelia and Uruapan in the State of Michoacan. The larvae occurred 

 singly or in small colonies containing as many as eight individuals, in 

 cells usually on the margins of the segments; the affected portions 

 were noticeably swollen, and the cells contained semidry tissue. From 

 one to several cells were present in each segment. The larvae pupated 

 within the cells, and the adults emerged in November. Damage was 

 minor where plant disease organisms gained entrance through the 

 cells and spread through the segments. In March 1928 this insect was 

 found in the pupal stage at Cuernavaca, State of Morelos; the adults 

 emerged in the same month. 



HYMENOPTERA 

 Chalcididae 



Two chalcidid species have been reared from prickly pear under cir- 

 cumstances that might indicate a phytophagous habit. However, it is 

 possible that both insects are parasites on cecidomyid larvae. 



TORYMUS Dalmaa 

 Torymus bifasciipennis (Gahan) 



A green and black callimomid with a long ovipositor, described as new 

 in 1936, was reared in numbers from segments of Opuntia tomentosa 

 collected at various points within 30 miles of Mexico City. The orange 

 larvae occurred singly or in colonies in cells beneath the areoles; the 

 adults emerged through the areoles. Large larvae and pupae were 

 present in March 1928, and the adults emerged in March and April. 

 A few specimens of the cecidomyid Mayetiola Keiffer sp. C. were reared 

 from the same segments. The Torymus larvae were found in various 

 stages of development in cells in which no Mayetiola larvae were 

 living. 



