288 Mr. B. I. Pocock on the Genus Theatops. 



The possession of but one dried specimen lias rendered it 

 impossible for me to give as complete a generic description as 

 is desirable. The characters presented by the mouth-parts 

 I have been unable to determine, and owing to damage to 

 many of the limbs I have been unable in every instance to 

 note the entirety of their tarsi and their spine-armature. 



Yet, in spite of these deficiencies, it must, I think, be ad- 

 mitted by every one, from a comparison of those characters 

 that are given, that the descriptions of Theatops and Opisthe- 

 mega have been founded upon specimens which are generically 

 identical. 



That Dr. Wood suspected the likelihood of this is evident 

 from his question, " Is it possible that Mr. Newport is mis- 

 taken as to the possession of eyes ? " 



Undoubtedly most of the mistakes that have been made 

 with regard to Theatops are referable to Newport's unlucky 

 expressions " ocelli distincti " and " ocellis inconspicuis late- 

 ralibus." For in addition to the doubt raised by the diifer- 

 ence of meaning between the two adjectives " distinct " and 

 " inconspicuous," it will be noticed that the sentence " ocellis 

 inconspicuis lateralibus " might mean one of two things, either 

 " inconspicuous eyes on each side " or " an inconspicuous eye 

 on each side." 



From the facts of the case it is only fair to presume that 

 Newport meant the latter. But most authors seemed to think 

 that he meant the former ; and being familiar with the four 

 distinct ocelli upon each side of the head in Scolopendra, they 

 very naturally imagined that Newport was referring to similar 

 structures when using the word " ocelli " in connexion with 

 Theatops. 



Now, although it is certain that in Theatops no distinct 

 ocelli such as are found in Scolopendra are to be observed, 

 yet there is upon each side of the head of the type specimen 

 of the former genus a distinct and well-defined area, which 

 occupies the position corresponding with the position of the 

 eyes in Scolopendra. 



This area appears as a somewhat oval whitish patch, differ- 

 ing only in colour from the substance composing the rest of 

 the head-plate. Upon the patch of the left side of the head 

 immediately behind the joint of the antenna there is to be 

 noticed a small brown spot, darker than the substance of the 

 head-plate. No corresponding spot occurs upon the right 

 side. 



No doubt these two whitish patches, which are probably 

 rudimentary eyes, are the features to which Newport applied 

 the words ocelli distincti and ocellis inconspicuis lateralibus. 



