54 THE VOYAGE OF H.M.S. CHALLENGER. 



Front femora less stout tlian in the male. 



Genital segments : first below longer than all the ventral abdominal segments together, 

 hind margin concave, posterior angles obliquely rounded. Second below with the edges 

 of the valves overlapping each other a little. 



The larva is similar to the adult (with the usual differences), but with the bases of 

 the front femora and antennae, as well as the under side of the body more widely pale, 

 and the leathery parts of the integuments above reddish-brown. The species occurs in 

 laro-e " schools " on the surface of the sea near Aden, and the larva), which seem to dislike 

 the wind more than the adults, take shelter in the lee of piers. 



9. Ilalohates proaviis, n. sp. (PI. II. fig. 1). 



Oblong, rather wider behind the middle. Slaty grey aljove and below. Head with 

 an oblirpxe transverse reddish-yellow spot on each side, nearly forming a band on the hind 

 margin. Antennae and legs fuscous brown. Gula, front acetabula at the margins, and 

 front coxaj at the apex ; most of middle coxa? ; sternum posteriorly, at least sometimes ; 

 a laro-e triangular brown-edo-ed blotch on the under outer side of the middle acetabula, 

 and the adjacent hind margin of mesosternum, as well as the greater part of the abdomen 

 below, yellow oehreous. Abdomen with first and second ventral segments in part, the 

 sixth at the sides, a spot at the base on each side of the first genital below, and the 

 tips of the horns of the second genital, more or less fuscous brown. Trochanters at the 

 apex, front femora with a long streak on the under side, middle femora with a spot at 

 the base below, as well as sometimes the disk posteriorly of the mesosternum, brownish 

 oehreous. Antennae: third joint about two-thirds the length of the second, fourth joint 

 subequal in length to second. Front tarsus : first joint nearly two-thirds the length of 

 the second. 



$ . Length 4, breadth I'S, middle femur 4-25 mm. 



Habitat. — Gilolo (British Museum and Brussels Museum). 



$ . Oblong, rather wider behind the middle. Slaty grey above and below. Head 

 with an oblique transverse reddish-yellow spot on each side at the hind margin, nearly 

 forming a band there. Antennas and legs fuscous lirowu. Eyes reddish-brown. Ros- 

 trum shining black. Gula, sternum posteriorly, at least sometimes, margins of front 

 acetabula and apex of front coxa3, a large triangular brown-edged spot on the under and 

 outer side of the middle acetabula, and the hind margin of mesosternum adjacent thereto, 

 most of the middle coxte, and most of the abdomen below, as well as genital segments 

 below, yellowish oehreous. Abdomen with the first and second ventral segments in part, 

 the sides of the sixth, a spot at the base of the first genital segment below, and the tips 



