464 BRITISH OEIBATJD^. 



rough ridges extend backward, almost to tlie hind 

 margin ; two of these, thinner than the others, are on 

 the extreme lateral edges of the abdomen ; two similar 

 but larger ridges run a little way within the margin ; 

 the space between these and the peripheral ridges on 

 each side is almost flat, or very slightly raised, and is 

 crossed by numerous short, irregular ridges, forming a 

 bond of union between the two longitudinal ridges. 

 The notogaster within the last-described longitudinal 

 ridges is considerably elevated along the median line, 

 gradually sloping down, having a shape like an inverted 

 boat (without a keel). The remaining two ridges 

 divide the notogaster into three longitudinal bands of 

 about equal widths, but the central band is narrower 

 anteriorly than posteriorly; and these ridges are shorter 

 than the others, where they cease posteriorly the 

 hinder portion of the abdomen is hollowed out, but 

 the actual hind margin is again raised, so that a basin- 

 like depression is formed. The whole notogaster has 

 sparse, irregular, round punctures ; the space between 

 the punctures is usually six or eight times the diameter 

 of the punctures. The hind margin usually has five 

 slight, rounded projections, with a minute knob 

 between each from which springs a thick, curved, 

 white hair ; there are six of these hairs, and three 

 similar hairs, but longer and less sharply curved, on 

 each lateral edge of the abdomen, a few smaller on the 

 progaster, and a row close to each of the two central 

 ridges. These last are omitted in the figure. 



The genital and anal plates are large and close 

 together, the former nearly square, the latter oblong, 

 narrowed posteriorly. The expulsory vesicles and 

 their pore for discharge, which is dorsal, are well seen 

 under favorable circumstances. 



Nymph. 



This nymph is the Nothrus palliatus of Koch, and 

 Berlese states* that he has examined the type specimen 



* " Acari, &c. Italiani," 'Notes,' fasc. iii, p. 13. 



