CACTUS-FEEDING INSECTS AND MITES 61 



average duration of the life cycle may be calculated as follows: mid- 

 summer, November-February, 60 to 90 days; autumn, January-May, 

 60 to 120 days; winter, February-October, 150 to 250 days. The 

 shortest period on record is 47 days at Sherwood in February and 

 March, divided as follows: egg stage, 5 days; larval period, 27 days; 

 pupal period, 15 days. 



Both in Argentina and in Australia two complete and one partial 

 generations occur annually, the peaks of moth emergence taking place 

 in November, January-February, and April-May. However, the gen- 

 erations overlap to a marked degree. In Argentina all stages of the 

 insect have been observed in every month of the year, and during 

 rearing operations at Sherwood the same conditions prevailed. 



Eggs of the summer generation may be laid at any time from Sep- 

 tember to early December; moths from these eggs may emerge as early 

 as December or as late as March. In 3 years' breeding work at Scone, 

 New South Wales, the majority of the summer generation moths 

 appeared in January. From 25 to 75 percent of the larvae hatching 

 from eggs deposited by these moths develop rapidly and produce 

 the moths of the autumn partial generation from late March to May, 

 while the slower developing larvae reach the adult stage in September 

 and October. The progeny of the autumn generation become adults 

 about 4 weeks later in October and November. In Argentina autumn 

 moths emerge most freely in June, and sporadic emergence occurs 

 throughout July and August. 



Parasites. — The two important parasites in the Argentine are the 

 tachinid Epicoronimyia mundelli and the braconid Apanteles alexanderi; the 

 former insect attacks the large larvae and emerges from the pupae. 



Tucumania porrecta Dyar 



Very little is known concerning this insect, which was described from 

 two female moths bred in early February 1925 from two larvae collected 

 the previous month at Paysandu, Uruguay. The larvae, deep-red or 

 purple-red with small dark spots, were feeding in segments of an 

 undetermined, and possible unnamed, low-growing Opuntia whose 

 characters suggested an affinity with 0. sulphur ea, one of the dominant 

 species of western Argentina. The larvae formed their cocoons within 

 the excavated segments. 



EREMBERGA Heinrich 



This is a North American group of three species, of which twoj 

 Eremberga creabates (Dyar) from California and E. insignis Heinrich from 

 San Luis Potosi, Mexico, are known from single captured specimens. 

 According to Heinrich (1956) their food plant is unknown. 



