and the Gonapophyses in the Dermaptera. 263 



In the Brachylabinae, I have examined the opisthomeres 

 of Nannisolabis formicoides. Here we have only two 

 plates : the basal one is about twice as long as broad, and 

 gently constricted about the middle ; this I take to be the 

 pygidium; the apical plate is of the same breadth, but 

 decidedly transverse, and this I take to be the meta- 

 pygidium, the telson having gone. 



Fig. 11. — Nannisolabis formicoides. Burr, (J. 



On Zacher's interpretation, the large basal plate is the 

 pygidium, the small apical one the metapygidium and 

 telson fused. 



At the external angles of the basal plate we see traces 

 of the crests or keels, or strong chitinisation which is so 

 well seen in the Psalidae figured, and in the metapygidium 

 of the Allostethids. 



In Labidura riparia we have an extreme form : there 

 are only two plates ; the pygidium shows no trace of suture 



Fig. 12. — Labidura riparia, Pall., 6 • 



or junction, is very large, and much longer than broad, 

 with the sides reinforced ; the apical plate or metapygidium 

 is very small and narrow, longer than broad. 



