90 U.S. NATIONAL MUSEUM BULLETIN 256 



in the vicinity of Cuautla. A few early adults were seen in April, but 

 general emergence occurred in July, reaching a peak late in the month. 

 After August the number of beetles in the field gradually diminished 

 until none could be located in late November. They feed high up on 

 the plants, chewing irregularly circular areas in the apical segments, 

 usually toward the margins. 



Oviposition extended from July to September, The mode of ovi- 

 position is distinctive in that the female gnaws a series of narrow 

 channels which form an irregular network two to four inches in di- 

 ameter; the narrowly elliptic white eggs are placed at intervals either 

 exposed in the channels or just beneath the surface at the bottom or 

 edges of these narrow galleries; up to 20 eggs have been counted in 

 one network. The number of eggs laid by individual females is un- 

 known, but dissection of several examples gave an average of 70 

 eggs. The incubation period in August occupied 10 days. 



Since the eggs are invariably placed on the main trunks and branches, 

 the larvae tunnel more or less gregariously in these woody stems. 

 They usually work downward, and by the time they reach full growth 

 may have burrowed several feet from the point of entrance. In Mexico 

 the earliest larvae were full-grown and had constructed cocoons in 

 November. At the end of February about 50 percent of the larvae 

 were in cocoons, but none had transformed to the pupal stage a month 

 later. The cocoons, composed of the inner fibres of the plant, are 

 bulky structures with a diameter or length attaining four inches; 

 in outline they are irregularly circular and rather flattened on the 

 sides; however, the shape is often determined by the free available 

 space. It was evident that one generation occurred annually. 



A. funestus was introduced into Australia in 1935 and is now firmly 

 established. In the field there is, as in Mexico, an annual generation 

 with the main emergence of adults in the midsummer months of 

 December and January. However under cage conditions at Gogango 

 in Central Queensland, where the rearing operations have been con- 

 ducted, two complete or almost complete generations are obtained 

 each year, with the peaks of beetle emergence occurring in November- 

 December and April- May; some adults emerge nearly every month. 

 The extra generation in the cages is attributed to the supplying of 

 moisture in dry periods, thus hastening pupation; on the other hand, 

 emergence in the field appears to await the midsummer rains. The 

 life cycle has been completed in as short a period as 105 days between 

 December and the end of March. Adults have been known to survive 

 for 112 days in summer and for 175 days during the winter months. 

 During the course of eleven generations at Gogango the average 

 return has been 12 beetles per female parent. On one occasion 342 



