26 ACARIDEA. 
towards the end, slightly recurved on the notogaster. Interlamellar hairs and tecto- 
pedia apparently wanting. Legs brown, bearing three claws and some bristles. 
Pteromorphe long, rather narrow, slightly coloured, brown, semitransparent, their 
anterior end protracted forward so as to nearly reach the top of the rostrum, rounded, 
the posterior end somewhat pointed; they are very flexible, and when closed com- 
pletely hide the legs, the whole body then assuming the shape of a small black seed. 
The minute texture of the pteromorphe consists of extremely fine wrinkles, which 
radiate from their point of insertion. The sides of the anterior part of the abdomen 
are slightly excavated for the reception of the pteromorphe. Anal plates larger than 
the genital plates, occupying a somewhat pentagonal area. Genital plates semilunar. 
Mandibles short, thick; the fixed branch bears four, the flexible branch five, short 
blunt teeth. Second joint of the palpi thick; the fifth joint bearing on its middle a 
claw-like, pointed, slightly curved tooth. 
Examples of this species were captured by me in the forests near Retalhuleu, where 
it lives on dead wood in damp places during the rainy season, in company with Hoplo- 
phora retalteca. 
Note.—0O. rugifrons being the only true Oribata observed by myself in the “tierra 
caliente” of Retalhuleu, it seems possible that the nymphal form of this genus 
delineated by me on Tab. XV., figg. 3, 3a-d, belongs to this species. Clusters of 
hundreds of individuals of these were found crawling on the underside of a piece of 
dead wood in a cacao-plantation near Retalhuleu on the 3rd of July, 1880. They bear 
a marked resemblance to those nymphal forms upon which Koch founded his genus 
Murcia, especially to his M. trimaculata (C. L. Koch, Deutschl. Crust., Myr. und Ins. 
Heft ii. p. 136. n. 21). 
The following are the notes which I then made on the living animal :— 
Body oblong, arched, broadly rounded behind, rather diminishing in size towards the 
somewhat blunt anterior end. Cephalothorax distinctly separated from the notogaster 
by a deep furrow, attenuated at its base, conical, large, triangular ; palpi projecting on 
the sides of the apex when seen from above. General colour greyish-white, the dark 
intestines shining through the smooth and transparent skin. In the angles of the 
abdomen on each side a globose, yellow, shining corpuscle. The dorsal surface bearing 
a few long pinnate bristles. On the legs the hairs more numerous, also pinnate, but 
shorter. First pair of legs the longest, the first and fourth pairs longer than the 
second and third. Tarsi with one claw only. Mandibles short, large, the fixed 
branch with four, the flexible branch with three teeth. Maxille of each side bearing 
four differently-sized teeth. The pseudostigmata looking like black eye-like spots. 
Two long bristles projecting on each side in front of the pseudostigmata. Long. 
0-5 millim. | 
