358 ON THE FED1FALFI OF NORTH AMERICA. 



sembles that of the cheliceres of a inygale. The "foot jaws" are situated just pos- 

 terior to these. Their aspect in each of the three families is somewhat characteristic. 

 In the Scorpionicte they are generally without spines and are provided with a con- 

 spicuous " hand " or swollen terminal joint. In the Thelyphonidse they are very mas- 

 sive, generally rather short and armed with a moderate number of often very large 

 and robust spines. In the Phrynidse, they are slender, more or less elongate, and 

 mostly provided with numerous long, acute spines. They appear to us to be the ana- 

 logues of the maxillse and- maxillary palpi of Coleoptera. Their first joint in the 

 Scorpionidse is very moveable, and doubtless fulfils the functions of maxillse. In the 

 Thelyphonidse, it is fixed, but serves as a "piece de resistance " to the man- 

 dibles. In the Phrynidse its motion is not at all restricted, and on the in- 

 ner side there is a well marked lobe. The remainder of the foot jaws, 

 appear to represent the maxillary palpi. They are composed of the same number of 

 articulations as is common among beetles. If these " foot jaws " are the maxillse 

 with their palpi, we ought to find sdme trace of the ligula, which in Coleoptera is 

 generally placed between or a little posterior to the maxillse. Now in the Scorpionidse 

 and Thelyphonidse, this exists as a hairy, membranous, conical, body, placed between 

 the basal joints of the maxillse. The labium is not distinguishable. The labial palpi 

 are almost entirely atrophied. But in the Scorpionidse along the inner side of the 

 first maxillary joint is a hairy membranous portion, which appears to represent that 

 organ. It is also traceable in the Thelyphonidse, but is lost in the Phrynidse. In 

 some of the Staphylinidse the labial palpi degenerate into mere filamentous appen- 

 dages. It is therefore not surprising to see them so degraded among the Pedipalpes. 



In the Phrynidse posterior to the maxillse is a corneous styloid process — we think 

 that this represents the ligula, although apparently articulated to the sternum. For 

 the mentum is probably in this family coalesced with, and forming the anterior por- 

 tion of the sternum. In the Scorpionidse two large processes spring from the base of 

 the anterior pair of feet. These form the posterior boundary of the mouth and seem. 

 to be the mentum. Two similar plates arise from the second pair of feet, these w.e 

 take to be analogous with the gula. In the Thelyphonidse these are all consolidated 

 into a single plate. 



It will be perceived that here there are represented all the more important ce- 

 phalics organs of the Coleoptera, excepting the antennse. Now is it not possible, 

 that the first pair of legs are misplaced and altered antennse ? The excessively elon- 

 gate and filamentous legs of the Phrynidse can be of no use as organs of progression, 

 and must apparently fulfil the functions of antennse, from which they do not differ 

 in form. And even those of the Thelyphonidse, seem scarcely fit for progress. In 

 both of these families, this first pair of legs articulates on a different plane from the 

 others, and entirely in front of the posternum. 



