^2 



accepted by Hansen; the lirst one was omitled, and we must admit quite correctly, 

 owing to the cylindric shape of the body in at least several species of Olpiiim L. K., 

 one of the Panctenodactyli. Besides the two characters mentioned above Hansen 

 sets forth a number of others, the value of which we are now going to discuss, 

 the one after the other. 



1) The first of these characters is for the Panctenodactyli (1894. 49. p. 230). 

 "The mandibles small, the distance between their exterior hind corner hardly more 

 than half as large as the breadth of the posterior margin of the céphalothorax and 

 mostly much shorter"; and for the Hemictenodactijli (p. 231) "The mandibles large; 

 the distance between their exterior hind corner at least as long as ^':i of the 

 posterior margin of ce])halothorax". This character is <|uile a good one and seems 

 to be without exceptions, but it is scarcely of paramount importance. The varia- 

 tion in size within each suborder is very marked; the differences in size between 

 the antennae of f. insl. Clithoniits terribilis n. sp. and Ideoroncns Siamcnsis n. sp., or 

 between a Chelifer Geof. and a Garypus L. K., are even more pronounced than the 

 difierences between those of a Olpium and a Ideoroncns, though the two last are 

 placed in different suborders. 



2) The second character for the Panctenodactyli is "Serrula on the movable 

 finger grown fast the whole length and posteriorly broader than anteriorly". And 

 for the Hemictenodactyli "Serrula on the movable finger free at the distal end, 

 posteriorly narrower than outside the middle." In the degree of the fusing of the 

 serrula exterior we have a character of great value and as it seems without excep- 

 tions; but it is nevertheless not surprising to find, that the relation between the 

 free and the fused portions of the serrulae differs in the genera of the Hemicteno- 

 dactyli. Those genera, which are related to the Panctenodactyli f. inst. Ideoroncns 

 laminalus n. sp., have only one fifth of their serrula free, while f. inst. Chlhonins 

 terribilis n. sp., which stands more apart, has two thirds free. The differences 

 found in the shape of the serrulae between the two suborders is less constant; in 

 Ideoroncns Mexicanus Bks. f. inst. the basal portion of this organ is scarcely narrower 

 than the distal (1905. 21. pi. IX, fig. 2 c) and in /. Siamensis n. sp. only slightly so 

 (PI. I. fig. 4 b). A difference in the shape of the teeth of the serrula is also found, 

 for they are as a rule more or less squarely-truncate in the Panctenodactyli, while 

 they are more or less pointed in the Hemictenodactyli; but a good many exceptions 

 from this rule are found. 



3) The third character for the Panctenodactyli is, "The immovable finger of 

 the mandibles with lamina exterior", and for the Hemictenodactyli "The immovable 

 finger of the mandibles without lamina exterior". Ideoroncns laminatns n. sp., one 

 of the Hemictenodactyli, which has a well developed lamina exterior (PI- 1, fig. 5 a), 

 forms an exception to this rule, which is nevertheless of both practical and pro- 

 bably also real systematic value. 



4) The fourth character is for the Panctenodactyli, "lamina interior plate- 

 formed, at most with slight incisions", and for the Hemictenodactyli "lamina 



