152 On some undescribed Gerrina?. 



anterior femora a little longer than the tibia?, the tarsi robust 

 and only a little shorter than the tibia?, intermediate legs 

 much longer than the posterior legs, the femora almost sub- 

 equal in length and shorter than the body, the intermediate 

 tibiae longer than the femora and much longer than the 

 posterior tibia?. 



All the specimens which I have seen are apterous. 



Naboandelus signatus, sp. n. 



Black ; thickly, shortly pilose ; head with the anterior and 

 inner margins greyish, the inner margins at eyes connected 

 at basal margin, ochraceous ; pronolum with a large central 

 ochraceous spot ; lateral margins of mesonotum greyish ; 

 body beneath bluish ; rostrum (excluding apex), an elongate 

 spot at posterior acetabnla, and the anal segment and append- 

 age ochraceous ; legs and apex of rostium black, more than 

 basal halves of femora ochraceous ; lateral margins of the 

 mesonotum somewhat longly pilose ; structural characters as 

 in generic diagnosis. 



Length, £ and ? , 2 mm. 



J Jab. Calcutta {J ml. Mas.). 



This species is found in the Calcutta tanks. 



Nacebus, gen. nov. 



Body subelongate ; head about as long as breadth between 

 eyes, the apex bioad and subtruncate, the lateral apical 

 angles distinctly subprominent, eyes inwardly somewhat 

 rounded or roundly truncate, not emarginate, not produced 

 over the anterior margins of the pronotum ; antennas with 

 the first and second joints stouter than third and fourth joints, 

 first joint about as long as head, second shortest, only a little 

 more than half the length of first, third and fourth subequal 

 in length, each a little shorter than first; rostrum reaching 

 the intermediate coxa? ; pronotum very short, almost appear- 

 ing only as a broad anterior collar ; mesonotum three times 

 as long as pronotum, the anterior and posterior margins 

 truncate, the lateral margins a little roundly oblique; abdo- 

 men (excluding anal appendage) about as long as head and 

 pro- and mesonota together, the anal appendage long and 

 slender; anterior legs moderately stout, the femora twice as 

 long as the tibia?, the anterior tarsi short, robust, about half 

 as long as the tibia?; intermediate legs much longer than 

 posterior legs, intermediate femora nearly as long as body, 

 the intermediate tibia? a little shorter than the femora, inter- 

 mediate tarsi about half the length of the tibiae. 



