Mesostigmata 



45 



MEGISTHANINA TRAGARDH, 1946 



Only a single family is contained in the Megisthanina. There is little 

 doubt, however, that it deserves group rank. Mites that belong to this 

 group have a unique genital opening in that the sternal plate appears 

 to function as an epigynial plate. 



Megisthanidae Berlese, 1914 



Figure 35 



Diagnosis: Megisthanids are large (from 1 to 

 4 mm.) mites, oval in shape, and their bodies 

 are divided into a gnathosoma and idiosoma. 

 The cuticle is present with a single dorsal plate 

 over the entire dorsum. The venter has an elon- 

 gated ventral plate, and the sternal plate is 

 divided into two parts, the posterior part of 

 which resembles an epigynial plate. No eyes 

 are present. A pair of presternal setae flank the 

 tritosternum, the palps are unmodified, and the 

 chelicerae are chelate and stout with strong 

 teeth. Legs are stout with toothlike projections 

 sometimes present on leg iv but there are no 

 claws on leg i. The female genital opening is a 

 crescent-shaped fissure placed just posterior to 



the sternal plate, while the male genital opening is located in the 

 sternal plate aperture and is closed by two plates between which there 

 is a transverse fissure. The stigmata are opposite the posterior legs 

 and have elongated peritremes. 



Figure 35 Megistha- 

 nus floridaniis Banks, 

 1904. Ventral view of 

 female. 



Genera: 

 1. 



Megisthanus ThoreW, 1882 

 Type. Megisthanus caudatus Thorell, 1882 

 Celaenogamasus Berlese, 1901 

 Type. Celaenogamasus hirtellus Berlese, 1901 

 Cyclothorax v. Frauenfeld, 1868 

 Type. Cyclothorax carcinicola v. Frauenfeld, 1868 

 Hoplomegistus Berlese, 1903 



Type. Megistanus armiger Berlese, 1888 {Megistanus is a lapsus of 

 Megisthanus) 



