EXPLANATIONS OF PLATE 23. 

 Ill^^nus ioxus. page 378. 



Fig. 1. The glabella and palpebral lobes of a lai*ge individual. 



Ill^nus imperator. page 332. 



Fig. 2. The glabella and palpebral lobes of a specimen of this species, natural she. 

 *' 3. The pygidium and part of four thoracic segments of this species, natural size. 



