15 



Hydroscapha has no anatomical connection, and it would seem almost impossible 

 that bo accurate and experienced an entou is Dr. Aube could have overlooked 



tin- conspicuous maxillary palpi of the insect lie was then describing; and, in 

 ration of this conjecture, 1 have received from Dr. Sharp types of Limnebius 

 Gyrinoides, taken at the .-aim- place and in company with h ipha, which 



their trui characters beyond the p of a doubt. 



In dried specimens, when the long abdomen of /. contracted, 



the resemblance between L. Gyrinoides and // I is so i lose that they might 



easily be mistaken for each other; but the most casual glance at the palpi and 

 antennae is at once sufficient to distinguish them. And, again, if the term 

 inoides be a ~ - i u' i : > 'I to //. Crotchii, by what name can the /.- be known? 



On every account, th< . it seems expedient to retain the uame Crotchii for the 



species described by I>r. Sharp. 



The elongate form and tin number of the corneous segments of the ahdomen 

 in Hydroscapha indicate an affinity to the Staphylinida, and thus that genus 

 presents a connecting link between the Staphylinida and the Trichopterygida, and 

 such appears to be its proper place in any systematic arrangement. 



Hydroscapha natans. 



//. natans, Le Conte, Trans. Am. I'.nt. Soc. v. p. 46, 1874 ; -Matthews, Essay 



Gen. Eydros. p. 16, 1876. 



L. c. ahd. retracto, ^ 1. = 1 mm. ; abd extenso, },- 1. = 1'75 mm. — Conica, vel 

 postice truncata, vel valde elongata, convexa, piceo-brunnea, nitidissima, pilis 

 brevibus albidis sparsissime vestita ; capite magno antiee rotundato, oculis magnis, 

 rotundatis; pronoto transverso, postice dUatato, distincte sal remote punctate; 

 elytris ovalibus, apicibus abrupte truncatis, ordinibus transversis sinuatis leviter 

 asperatis ; ahdomine elongate, ad apicem valde attenuate, atia uuiuque 



apertis; pedibus atque antenuis pallide flavis, his ad apices infuscal 



ovate, either truncate or elongate posteriorly. 



// ad large and broad, alutaceous, shining, remotely punctured, with the clvpeus 

 rounded and divided from the vertex by an arcuate suture : eyes large and 

 rounded; antennas sh yellow, with the club dusky. 



/ orax short, transverse, rather longer and much broader than the head, v.. 



the base, shining, indistinctly alutaceous, remotely punctured, sides Blightly 

 margined and rounded, anterior angles produced, basal margin faintly sinual 

 with the angles slightly acute. 



Scutellum large, triangular. 



Elytra very convex, longer and rather broader than the head and thorax, widest 

 before the middle, faintly asperate in transverse rows, interstices alutaceous, 

 suture elevated. i-ihtly round- d, extremities abruptly truncal 



Abdomen convex, long and much attenuated posteriorly, aigro-piceous, alutaceous, 

 with fiv( . Bhining and remotely punctured, basal segment 



d< Qsely pubescent, the apica - marginate at the apex, and longitudinally 



impn 3sed throughout its whole length. 



Legs rather long, testaceous. 



Under parts aigro-piceous, mouth yellow. 



Differs from //. Crotchii in it- larger size, broader form, sculpture of each part of 

 the body, Bhorter antenna, and aigro-piceous colour. 



Habitat, North America. Found in a river near Los Angel lifornia. by Mr. 



(.. R. Crotch. 



