6 Mr. MacLeay on some new forms of Arachnida. 



Head not distinct from thorax. Body very flat on the ground 

 with the legs also extended flat on the same surface. Ab- 

 domen soft with six fusi. 

 Of the genus Selenops Walckenaer gives three subgenera, 

 Omalosoma, Apharteres, and Aissus. Near to the latter comes 

 the following additional form of Selenops, which I shall call 

 Hypoplatea, 



Subgenus Hypoplatea. 



Antennas with two teeth on the inner side of the groove of first 



joint. 

 Eyes, the two lateral ones of the arch rather oval in form. 

 Maxillae subparallelogrammic, being obliquely truncated at 



the inside. 

 Maxillary palpi having their terminal joint the longest and 



crowned with an unguis. 

 Mentum semicircular. 



Sternum suborbicular, but posteriorly emarginate. 

 Abdomen as wide as the cephalothorax. 

 Feet, the last pair but one the longest. Tarsi having a cushion 



surmounted by two very minute ungues. 



Sp. 2. Hypoplatea celer. — Hypoplatea flavescenti-grisea, abdomine 

 fascia apicali nigra emarginata terminato ; ad basin tripunctato, punctis 

 inter pilos ochreo-flavos nigris ; femoribus trifasciatis fascia media fulva 

 utrinque nigra fasciis externis nigris; tibiis subfasciatis. 



Long. 6J lines. 



This species is common in Cuba, darting in the rainy sea- 

 son with extreme velocity over the plastered floors. Its body 

 and legs are extended so flatly on the surface on which it 

 moves, and moreover it has the Thomisidous faculty of run- 

 ning backwards so strongly developed, that it is sure, along 

 with various little lizards of the subgenus Sphceriodactylus, to 

 attract the attention of new comers, when, owing to certain 

 qualms inside and torrents of rain outside, they shut them- 

 selves up in their apartments to ponder gloomily over the 

 novelties of a West Indian climate. I possess other species 

 of the genus, but which belong to Walckenaer's subgenus 

 Aissus, and which are only to be found on the trunks of trees. 

 These are seen like a ray of light to flash before the entomo- 

 logist when they have been dislodged by his stripping off the 



