the British Species of Heterocerus. 163 



Heterocerus laivigatus, Erichs. Ins. Deutschl. iii. 518, 8. 



■ Marsham't, Steph. Illustr. ii. 101, 3; Man. 80, G^Oo. 



jmsillus, Waltl. Isis, 1839, 221, 23. 



As this is the commonest London species, and has the pale 

 markings very complete, I sliall describe the insect in some detail, 

 and compare the other British species with it. Oblong, black, 

 densely clothed with a fine ash-coloured pubescence, almost with- 

 out any admixture of long hairs excepting on the sides of the 

 thorax, where they are pretty plentiful ; jaws pitchy, or often 

 ferruginous. Thorax transverse, rather narrower than the elytra ; 

 contracted in front ; the sides moderately rounded ; the hinder 

 margin obliquely truncated on either side ; the posterior angles 

 obtuse, and very narrowly margined — that, is to say, they have a 

 delicately impressed line immediately within the outer margin, 

 and which follows the outline of the thorax ; this may be traced 

 along the whole of the posterior margin, and at the posterior 

 angles, but extends very little way up the sides.* Elytra nearly 

 four times the length of the thorax, with the humeral angle some- 

 what rounded, and more prominent than the broadest part of the 

 thorax ; the sides at first straight and parallel, but at a short dis- 

 tance below the shoulder they are slightly dilated and rounded; 

 the apex is obtusely rounded. Anterior tibiae dilated, rounded 

 externally at the apex ; the outer margin denticulate, and fur- 

 nished with spines ; these are usually about seven in number on 

 the outer side of the tibiae, and three at the apex ; the longest are 

 near the apex, and their length is very nearly equal to the width of 

 the tibia at the same part ; sometimes eleven of these spines may 

 be counted. With regard to the colouring, there are two varieties, 

 one in which the markings are very pale testaceous, the sides of 

 the thorax pale testaceous, but interrupted in the middle, and the 

 sides of the abdomen and the legs likewise pale. Specimens pre- 

 senting these conditions are common in collections, and are perhaps 

 somewhat immature. In others the markings are rufo-testaceous, 

 the sides of the thorax almost immaculate as well as those of the 

 abdomen, and the legs are more or less pitchy, especially the 

 tibiae. 



[In the common type of the markings on the elytra, the Hete- 

 roceri have a post-humeral band, which, entering the elytra form 

 the outer margin, run inwards a short distance, and then is sud- 

 denly recurved, and running upwards encloses a small dark area 



• This impressed line is seen in all the Ileteroceri here noticed, excepting " H. 

 fossorV and H.Jleiuosus. 



