144 Scientific Proceedings, Royal Dublin Society. 



which are paler. Abdomen deep-brown dorsally, except the last 

 (button-shaped) segment, which is clear yellow. Beneath, the 

 head is. brown, the prosternum blackish-brown, and all the rest 

 of the insect dusky-yellow. Front acetabulse, coxse, and tro- 

 chanters very pale ; femur brown, yellowish beneath, with a 

 sharp prominent black tooth at its proximal inner edge, a row of 

 fine teeth along the edge, and a large double one near the inser- 

 tion of the tibia ; tibia with one strong and two small black teeth 

 on its inner edge, and a comb-like row of bristles near its distal 

 end. Middle and hind legs brown ; middle femur with row of 

 spines along its inner edge. All legs with numerous long pale hairs. 

 Length 3 -3 mm. ; breadth 1-3 mm. Length of anterior 

 femur, 1-8 mm. ; of middle femur, 2*3 mm-. ; of hinder, 2 mm. 

 Total length of a leg of the second pair, 5-4 mm. 



G-enus. — Halobates, Eschs. 



Halobates regalis, sp. nov. 



(PI. XIII., figs. 1-8.) 



Oval ; broadest behind the middle ; deep blue-black above, and 

 at sides, but with dense silvery pubescence ; creamy yellow below. 

 A pair of distinct light yellow triangular markings on the head, 

 towards its hinder margin. Eyes rich-brown when in spirit ; 

 black when dry. Antennae black, with proximal part of first 

 joint light yellow ; fourth joint slightly longer than third, but 

 shorter than second. Legs black (but the femur of the first pair 

 in the female has a clear, orange-yellow, longitudinal mark above 

 at its proximal end, and is creamy yellow for the proximal third 

 of its length beneath). Front tarsus with the second joint nearly 

 twice as long as the first (PI. xiii., fig. 5). Middle tarsus with its 

 first joint three and a-quarter times as long as the second (PI. xiii., 

 fig. 6). 



Male (PI. XIII., figs. 1, 2). Length, 5 mm. ; breadth, 2-25 mm. 

 Length of front femur, 2 mm. ; of middle femur, 5-5 mm. ; of hind 

 femur, 5 mm. Total length of a leg of middle pair, 13 mm. 



The segments of the abdomen (PL xiii., fig. 2) are deep blue-black 

 above ; but those which are visible show a light yellow posterior 

 margin. The last (third genital) segment is deep blue-black, 



