192 Prof. J. O. Westwood's Notes on the genus 



to agree almost entirely with the Madagascar specimens of 

 Latreille. 



The semicircular head in the animal itself exhibits in 

 front of its upper surface a distinct transverse upper lip, 

 and on its under surface a decidedly marked triangular 

 space, the former corresponding in position with the upper 

 lip, and the latter evidently representing an under lip 

 or mentum — of neither of these parts is there any trace in 

 M. Joly's figure.* The antenuse are extremely small and 

 scarcely extend beyond the impressed spaces in Avhich 

 they are inserted. With the exception of the triangular 

 space above noticed the under surface of the head is flat 

 and entire, exhibiting no trace (in all the specimens of 

 both species) of any of the mouth organs or mask spoken 

 of by Latreille and Joly, the latter of whom represents the 

 trophi as, apparently, partially visible through the flat 

 under-covering of the head. The ocelli represented by 

 M. Joly appear to me to be very questionable. Between 

 the antennal impressions are two minute punctures placed 

 transversely, and behind them a small central tubercle. In 

 P. variegatum there is a very slender, waved, raised line 

 in front of the eyes, like a pair of tubercles, within Avhich 

 this line is directed nearer to the hind margin of the head, 

 having between it and the margin two small dark dots, 

 which have been regarded as the posterior ocelli by 

 M. Joly. The large entire carapace, convex and longi- 

 tudinally ridged above and flat beneath, entirely recalls to 

 mind the shell of a tortoise. The sternum is clearly 

 divisible by slight impressions into three parts, f the an- 

 terior (prosternum) being more distinct than the others 

 and considerably longer and more distinct than is repre- 

 sented by M. Joly. Tlie mesosternum terminates between 

 the base of the middle legs, and the metasternum seems 

 formed of four pieces, the first terminating transversely 

 between the third pair of legs, whilst the other three 

 divisions form the triangular space extending to a point as 

 far back as the extremity of the posterior femora. Here 

 there is a distinct transverse articulation forming a joint, 

 considerably narrower than the hind part of the carapace, 

 obliquely truncate on each side. This articulation is the 

 part represented in M. Joly's figure 3, as C 5, but which 



* Both these structures are, however, indicated in M. Joly's more recent 

 figures, 

 f None of these divisions are indicated in M. Joly's recent figures. 



