TWO NEW SPECIES OF THE GENUS LASIOSEIUS ( MESOSTIGMATA : ASCIDAE ) FROM INDIA

The mites of the genus Lasioseius Berlese, 1916 are very little knowp from Indian region. Prior to this study, only six species of Lasioseius were known from India. Chant (1960) described one new species of Lasioseius from citrus tree in Assam. Bhattacharyya (1968) described two new species from the soils of West Bengal. Ramdas and Ghai (1968) also described a new species from wheat plant in Delhi. Later, in 1992 one new species was described from bird's nest in West Bengal by Gupta and Paul. Recently Bhattacharyya et al. (1997) described one new species from squirrel nest in West Bengal.

JS all setae serrated; Z4 and ZS five and six times longer than JS (11.1); lateral membrane with 4 pairs ,of simple marginal setae (Fig. 1).
Tectum minutely denticulate (Fig. 3); pedipalp composed of five segments, all setae simple; specialized seta on pal pal tarsus with two tines.Movable digit of chelicera provided with four teeth, fixed digit multidentate (Fig. 4).Hypostomal setae nonnal for genus.Ventral groove of gnathosoma with four rows of deutosternal denticles, with II-IS denticles in each row.
Legs I-IV with well-developed claws and pulvilli.

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Tritosternum bipartite with sparsely pilose lacinae; stemiti-genital'shield with genital aperture situated on anteromedian region and with 5 pairs of setae.Ventri-anal shield bearing 5 pairs of setae (excluding a pair of para-and a post-anal setae), para-anal setae at mid-level of anal aperture.Peritreme, peritrematal and exopodal shields same as in female.
All legs with ambulacra and claws.
Remarks : Lasioseius indicus sp.nov.superficially resembles with L. lindquist; Nasr and Abou-Awad, 1987, in having the same number of dorsal and ventral setae and similar pattern of reticulation of dorsal shield but the new species can be readily separated from L. lindquisti by following characteristics: shape of sternal, peritrematal and exopodal shields and tectum, very large endopodal plates, placement of sternal setae I in relation to anterior margin of sternal shield and number of teeth on fixed digit of chelicera.
Tritosternum with a long• basal part and a pair of sparsely pilose lacinae.Pre-sternal area lineated.Sternal shield (129.5 long, 129 .5 wide) well-developed, uniq!le reticulation along anteromedian region and with fine granulation; first pair of sternal setae p1aced on anterior margin of sternal shield; metasternal shield bearing a seta; genital shield partly granulated, widened behind genital seta, posterior margin truncate.Ventri-anal shield IS 1.7 long and 188.7 at widest point, reticulated, bearing 3 pairs of setae (excluding a pair of para-and a post-anal setae); paraanal setae at mid-level of anal aperture; post-anal seta largest; six pairs of setae around ventrianal shield behind coxa IV, posterior.most largest.Large stigmatal opening between coxae III and IV; peritreme visible dorsally, reaching seta z I; peritrematal shield broadly connected to exopodal shield 'posteriorly, ventral region posterior to coxa IV striated irregularly (Fig. 12).Apotele two-tined; pedipalp five-segmented.Fixed digit of chelicera with 12 small teeth arranged in a row along its cutting edge, movable digit with 5 teeth (Fig. 13).Gnathosoma with 4 pairs of setae of which hyp2 largest.Ventral groove of gnathosoma with seven rows of deutosternal dentic les'.
Remarks: Lasioseius sahai sp.nov. is similar to L. reticulatus Bhattacharyya, 1968 in having lanceolate type of ~ae, similar reticulation of dorsal shield and by the shape of genital shield.However, the new species can be readily distinguished from the latter by the differences in number of setae on dorsal shield, ventri-anal shield and ventral interscutal membrane, shape and number of metapodal plates, shape of endopodal and peritrematal plates and number of teeth on fixed digit of chelicera.
The species is named after Shri S.S. Saha, collector of the species.
Male: Dorsal shield 240.S long and 466.2 wide, faintly reticulated with 22 pairs of simple to pilose setae; 12 pairs on anterior region, humeral setae (r3) 70.3 long; posterior region with 10 pairs of se,tae, ZS and Z4 nearly five times longer than JS (14.8); two pairs of simple marginal setae on lateral membrane (Fig. S).