154 Mr. R. I. Pccock on the 



distinct lines of sensory pores. Dorsal with 14 or 15 rays, 

 originating at equal distance from occiput and from root of 

 caudal. Anal exactly opposed to dorsal, with 15 or 16 rays. 

 Pectoral ^ to § length of head. Caudal truncate. Caudal 

 peduncle i\ as long as deep. Scales thin, imbricate, with 

 concentric striae, 31 to 33 in a longitudinal series, 12 to 15 

 in a transverse series ; belly and axillary region naked. 

 Brownish above, with more or less numerous darker spots 

 and dots and a blackish lateral streak ; belly white ; dorsal 

 and caudal fins dotted with blackish. 



Several specimens were collected by Mr. G. Ockenden 

 at Tirapata, Eastern Peru, at an altitude of 13,000 feet. 

 The largest female with mature ova measures only Qo milli- 

 metres. 



In its small size this new species approaches 0. elegans^ 

 Garraan, in which the eyes are nearer together (one diameter 

 apart), the origin of the dorsal fin is nearer the occiput than the 

 root of the caudal, and the scales are smaller (34 to 36 in a 

 longitudinal series) and so thin as to be hardly visible, 

 according to Dr. Garraan's description. 



This species departs less than any other of the genus 

 Orestias from the normal Cyprinodont pattern, and but for 

 the absence of ventral fins would be taken for a Fundulus. 



XXI. — The Stridulating-organ in the Egyptian Beetle^ 

 Graphipterus variegatus. By K. I. POCOCK. 



Some six or seven years ago Mr. Erskine Nicol told me that 

 there is a spotted ground-beetle in Egypt which makes an 

 audible scraping sound as it runs over the sand. I supposed 

 from his description that the insect belonged to the Carabid 

 genus Anthia ; and knowing that Mr. C. J. Gahan was 

 collecting facts for a paper upon the stridulating-organs of 

 the Coleoptera, I suggested that an examination of Anthia 

 might bring to light a new organ of this nature. No such 

 organ, however, could be found ; and there the matter was 

 allowed to rest. In July of the present year, however, 

 Mr. J. E. Nicol brought to me, with some Arachnids and 

 insects collected at El Khanka, near Cairo, a specimen of 

 Anthia and two otlier beetles of the smaller but allied form 

 Graphipterus variegatus, Fabr. Pointing to the latter, he 

 said, " That is the beetle that makes the noise, not the large 

 kind. When running, it sounds as if it were hollow and 

 partly filled with grains of dry sand." 



