[Scanning electron microscopic observation on morphology of ].

Objective: To observe the morphological characteristics of live at different stages of life cycle and its ultrastructure.

Methods: The live specimens were isolated from longan pulp, and firstly rinsed with double distilled water under a light microscope to make slide preparation by the conventional manner, and then were made into scanning electron microscope (SEM) specimens. The specimens were observed under SEM for the ultrastructure characteristics at different developmental stages including egg, larva, nymph and adult (male and female) .

Results: The SEM photographs showed that the egg was oval and milky. The larva had three pairs of legs, without genital setae, preanal seta and coxal rod, and there was no trace of genital growth. The nymph had four pairs of legs, genital seta and preanal seta, whereas the genital area was looked still under-developed. The male adult had a conical gnathosoma and a pair of external verticals which were longest setae at the dorsal idiosoma, whereas the other dorsal setae were all short rhabdoid. At the ventral idiosoma, there was an aedoeagus which was like a bent cube, and the top was straight forward. The external sacral setae and post anal were longest setae. The female adult's genital plates were a composite of plastron and cutex inner root, covering the genital tract, and a hole of anus and a pair of anal setae were located at posterior of idiosoma.

Conclusions: The morphological characteristics and ultra-structure of at different stages of life cycle can be vividly observed under SEM, which provides the morphological bases for further study of the relation between parasitism and disease.