84 



Thorax rather small, broader and rather longer than the In ad, widest beyond the 

 middle, abruptly contracted towards the base, indistinctly alutaceous, with a 

 deep and broad medial line, nut extending to th< bas< or apex, and a Bhorter 

 parallel line on each side extending from the middle of the disc nearly to the 

 basal margin, Bides margined, rounded m front and contracted behind, basal 

 mar-in straight, with the angles right angles. 



ScuteUum small, triangular, with a faint longitudinal impression on the disc. 



Elytra oval, rather broader and more than one-half longer than the head and 

 thorax, widest near the middle, distinctly but faintly asperated in transverse 

 rows, with the interstices alutaceous, sides margined, apex entire, obtuse. 



Legs rather robust, bright yellow. 



Under parts rufo-castaneous, with the coxa- bright yellow. 



Differs from /'. incognitum in its much smaller size, rufo-castaneous colour, less 

 convex form, totally diverse sculpture, as well as in the Bhorl and broad lateral 

 lines on the thorax. From the other allied species it is distinguished by the 

 lines on the thorax being parallel to each other. 



IIahit.it, Europe. Found by Mr. Crotch in Cambridgeshire, aud by Mr. Morris near 

 Lewes, in Sussex. 



This insect appears to he the true Ptilium affine of Erichson ; it agrees in size, 

 colour, and sculpture with his description in the " Ins. Deutsch." I had formerly 

 received \\ pes from two contim ntal sources labelled " P. affine," which were identical 

 with the insect I found in Wicken Pen, and described as P. affim in my former work, 

 the ' Trichopterygia LUustrata.' 



I have now separated this species under the name P. incognitum. It is much 

 larger than the /'. affine of Dr. Erichson, nearly black, much more convex, and very 



diverse in sculpture. 



The discrepancy of size and form existing bei ween my own specimen and those 

 subsequently taken in this country first drew my attention to the subject, and con- 

 vinced me that they could not belong to the 9ame species. 



The change of nomenclature does not, however, affect any but my own speci- 

 men; all the other Ptilia with parallel lines on the thorax which I have hitherto 

 seen belong to Ptilium affine, Erichs. 



Ptilium incognitum. 



P. incognitum, .Matthews. Ann. Mag. Nat. Hist. I), iii. p. 195, 1889. 



P. affine, Matthews nee Krichson, Trich. Illust. p. 99, pi. xxii. tig. 5, 1872. 



L. c. t \. ,';, lin. = - 87-l mm. Elongato-ovatum, nigro-piceum, valde con- 

 vexum, leviter et confertim tuberculatum, pilis hrevihus argentcis sparse vestitum, 

 pronoto ad basim constricto, lineis tribus rectis, lateralibus parallelis, in disco im- 

 presso; capite parvo, convexo, antice elongato, leviter confertimque tuberculato; 

 oculis parvis, band prominentibus ; pronoto modico, capite parum latiori, vix lon- 

 giori. pone medium latissimo, basim versus abrupte fortiterque constricto, confertim 

 tuberculato, lineis tribus rectis in disco distinctissime impresso, marginem utramque 

 hand attingentibus, media longissima, lateralibus parallelis atque ad extremum 

 utrumque minute uncinnatis, margins basali fere recta, angulis prominulis, acutis, 

 angulis anterioribus valde deflexis ; elytris ovatis, convexissimis, capite atque pronoto 

 multo latioribus, et duplo longioribus, pone media latissimis, ad humeros valde 

 attenuatis, leviter confertimque tuberculatis, atque tuberculis majoribus hie et 

 illie ornatis, lateribus marginatis, apice obtuso, dilution ; abdomine parum exserto, 

 valde obtuso, pedibus longioribus, Isste tlavis ; antennis longis, piceis, ad bases 

 dilutioribus. 



Body elongate-ovate, nigro-piceous, very convex, finely and closely tuberculato, 

 sparingly clothed with short silver hair, with three straight parallel lines on 

 the thorax. 



