OCHYROCERA. 45 
Fam. LEPTONETIDA. 
OCHYROCERA. 
Ochyrocera, E. Simon, P. Z. 8. 1891, p. 565. 
Type Ochyrocera arietina, E. Sim.: Antilles, St. Vincent. 
1. Ochyrocera simoni. 
Ochyrocera simonii, O. P.-Cambr. Biol. Centr.-Amer., Arachn. Aran. i. p. 122, t. 17. figg. 13, 
13 a-d(¢)’. 
Type, ¢, in coll. Godman & Salvin. 
Hab. Mexico, Teapa in Tabasco (H. H. Smith?). 
Fam. FILISTATID. 
Lung-sacs two; tracheal stigmata migrant, convergent, situated halfway between the genital rima and the 
spinners. Spinners six; calamistrum and cribellum present. Two pairs of sternal sigilla sometimes 
present. Palpal bulb of male very simple. Mandibles soldered together at the base, forming with the 
labium and maxille a stout, haustellate proboscis. No strie present on the outer side of the mandibles. 
Eyes eight, closely grouped in the centre of the cephalic area. Tarsal claws three. Superior claws 
with a single row of ten to twelve teeth, inferior claw sometimes with one or two. 
There is considerable difficulty in ascertaining exactly where the Filistatide should 
be placed amongst the other families of the section Arachnomorphe ; and the same 
remark applies to all the other cribellate forms, and also to others not cribellate. No 
linear arrangement, such as one is compelled to adopt in a printed work, can in any 
way convey a correct idea of the affinities of different families. 
With regard to the cribellate forms, there appears to be no reason why the cribellum 
and correlated calamistrum should not have become independently specialized in 
several different groups, each of these groups falling under different surrounding 
influences as they developed. The appendages which have been converted into the 
cribellum have survived in these cases, and are now obsolete in other forms recognized 
as non-cribellate. The rudiments of the cribellum, and bristles adapted for specializa- 
tion as a calamistrum, were probably possessed at one time by all existing forms 
of spiders; while a more or less highly specialized form of each was characteristic of 
certain large groups, not necessarily otherwise closely allied. 
In some groups these rudiments and specializations have been retained, and in 
some they have more or less entirely disappeared, while at the same time further 
differentiation and specialization under various influences was taking place in different 
directions. This will account for the presence of a highly specialized calamistrum and 
cribellum amongst forms which are otherwise, obviously, not in any respect nearly 
related to each other. 
The possession of sternal sigilla, the character and grouping of the eyes, as well as 
the simple form of the palpal bulb, would seem to show that the Filistatide are alone 
