140 CLAVICORNIA. [Ptenidium. 



marked, and it is also less convex on the upper surface ; the colour is 

 sometimes lighter. L. |-1 mm. 



Rare ; Gumley, in vegetable refuse ; under birch bark, Scarborough (Wilkinson) ; 

 Mabberley, Cheshire (Chappell) ; Northumberland district (Bold) ; Scotland, Forth 

 district (Sharp). 



This species has been regarded as a variety of P. evanescens, but 

 appears to be distinct. 



P. Kraatzii, Matth. Ovate, pitchy-black, very shining, very 

 sparingly clothed with extremely short yellow hairs ; head moderate, 

 with two or three large punctures near each eye, eyes large and pro- 

 minent, antennas long, clear yellow; thorax rather small, broadest at 

 middle, sides evenly and not very strongly rounded, with four plain 

 foveae at base, the interior pair much smaller than the exterior ; head 

 and thorax shallowly punctured ; scutellum large, with four impressed 

 punctures at base ; elytra dark rufo-piceous, often almost black, ovate, 

 broadest before middle, distinctly punctured in rows, apex lighter; 

 legs clear yellow ; under-side rufo-piceous, mouth and coxa3 yellow. L. 

 | mm. 



In nests of Formica fusca ; rare; first taken by Mr. Foxcroft in Scotland, pro- 

 bably near Raunoch, and subsequently found by myself in refuse taken from ants' 

 nests in Buddon Wood, Leicestershire. 



This species differs from P. formicetorum by its somewhat smaller 

 size, narrower form, and more distinct sculpture, and also by the usually 

 darker colour of its elytra. 



P. formicetorum, Kr. Ovate, rather short, very convex, glabrous 

 and shining, head and thorax black, elytra rufo-piceous, or rufo-castane- 

 ous, sparingly clothed with silvery hairs ; head moderate, with two 

 foveae on vertex, eyes rather small, not prominent, antennce rather short, 

 clear yellow ; thorax very smooth and shining, dilated behind, broadest 

 behind middle, with four minute fovese at base and two very small ones 

 near anterior margin ; scutellum moderate, with three small punctures 

 at base ; elytra ovate, rather short, very convex, broadest before middle, 

 punctured iri rows ; legs clear yellow, tarsi slightly dilated; under-side 

 rufo-piceous, with head, coxas, and abdomen lighter. L. f-|- mm. 



In nests of Formica rufa and F. fuliginosa ; local; Chatham, Tilgate, Esher; 

 Guestling, Hastings; Edgbaston ; Button and Knowle near Birmingham; Wi thing- 

 ton, Cheshire ; Liverpool district ; Northumberland district ; a small, dark form 

 occurs near Liverpool. 



P. turgidum, Thorns. Very broad, turgid, and convex, dark pitchy- 

 red, sparingly clothed with very short silvery hairs ; head rather short 

 and prominent, eyes large, strongly prominent, antenna? pale yellow, 

 with the last two joints darker ; thorax widened behind, broadest a 

 little before base, with four small foveas near base and two minute fovcas 

 near anterior margin ; scutellum short and broad ; elytra rather short 



