Egg . The egg of the citrus rust mite is round, white or pale 

 yellow, with a smooth surface approximately .03-. 04 mm in diameter 

 (Swirski and Amitai, 1958). Yothers and Mason (1930) referred to de- 

 tection of a folded larvae visible within the egg a few hours prior to 

 hatching. Both Yothers and Mason (1930) and Swirski and Amitai (1958) 

 found the egg incubation period to be 3.1 days. 



Larva . Swirski and Amitai (1958) described the first and second 

 stages of the citrus rust mite. The first stage is white and measures 

 about .08 mm in length. The second stage ranges from .10 to .12 mm and 

 is pale yellow. Developmental times varied according to temperature 

 with 3.1 days at 32.6°C and 10.7 days at 25.1°C (Yothers and Mason, 1930) 



Adult . The adult citrus rust mite is generally wedge-shaped, pale 

 yellow, and 1/200 in. long (Muma, 1965). The adult becomes light brown 

 to brown with age (Swirski and Amitai, 1960). The female is 0.15-0.16 

 mm in length and lives up to 16 days at 26°C (Swirski and Amitai, 1959) 

 while the male is only 0.13-0.14 mm in length (Keifer, 1938; Swirski and 

 Amitai, 1959). 



Sex determination . Yothers and Mason (1930) described the citrus 

 rust mite as parthenogenetic when they were unable to find any males. 

 Ebling (1959) found 39% males present in units of 144 individuals. 

 Swirski and Amitai (1960) recorded males to be present throughout the 

 year with increase in spring and decrease numbers in autumn. 



Independent observations were made by Oldfield et al . (1970), 

 Sternlicht (1970), and Sternlicht and Goldenberg (1971) as to the occur- 

 rence of spermatophores in Eriophyidae' and the females self-fertilization 

 (laying eggs resulting in offspring of both sexes, as opposed to un- 

 fertilized females which lay parthenogenetic eggs bearing only male 



