1868.] 207 



Protini, and would appear to have a varied range of habits ; for, though always 

 found by me in fungi, hot-beds, or other vegetable matter, Erichson, as above 

 mentioned, states that they live under bark, and Mr. F. Smith has observed that 

 one of them is parasitic upon Saperda popuhiea. The latter peculiar habit is 

 recorded in Westwood's Introduction, vol. i., p. 365 (note). Kraatz erroneously 

 quotes Westwood as stating that the larva of a species of this genus is parasitic 

 upon the Saperda; but, whether larva or perfect insect, it seems to me that any 

 connection between the Staph, and Longicorn could only have been through an 

 accidental association. 



1. Megarthrus depressus, Payk., Er,, Kz. This very abundant species may 

 be described as a type with which the others are to be compared. It varies slightly 

 in size, the largest being IJ lin. in length, and is dull black in colour, almost 

 entirely opaque, and very delicately pubescent, with the legs reddish-ferruginous, 

 except the femora, which (and especially those of the hinder pair) are pitchy -black ; 

 the elytra, also, are of a pitchy-brovra tinge. The thorax (in the outhne of 

 which the principal superficial distinctive characters of these insects are to be 

 looked for) is scarcely, if at all, wider than the elytra, and has a very distinct 

 longitudinal medial channel ; its anterior angles are obtuse and its sides gently 

 rounded, the hinder angles being slightly notched out, vrith the angles formed by 

 the lateral and basal ends of the emargination slightly obtuse. 



In the male all the legs are stouter than in the other sex ; the posterior 

 femora are thickened, with the tibiae slightly curved. Erichson and Thomson omit 

 any reference to the ventral characters, which are, however, pointed out by Kraatz ; 

 the penultimate segment of the abdomen beneath (which, with the apical segment, 

 is abruptly ferruginous-testaceous in colour) having a nearly semicircular notch in 

 the middle of the hinder margin, and the ante-penultimate segment being slightly 

 cut out in a somewhat semicircular way for its entire width, so that it is shallowest 

 in the middle. 



The entirely dark colour of this insect will serve to separate it from all our 

 recorded species but M. sinuatocollis, from which, however, it may be easily 

 separated by the absence of any indication of angulation in the sides of its thorax, 

 which, moreover, is narrower, its greater opacity, the incurved middle tibiae in the 

 male, &c. 



2. M. NiTiDULUs, Kraatz, Ins. Deutschl. ii, 1028, 2. This insect, not yet 

 recorded as British, does not appear to have been observed out of Germany, judging 

 from De Marseul's last European Cat. ; it seems also to have been unknown to de 

 Saulcy. Kraatz states it to be allied to M. depressus in the structure of its thorax, 

 but to be readily distinguishable from that species through its legs and the basal 

 joints of its antennae being red. It seems also, apart from thoracic characters, to 

 differ from M. sinuatocollis in its somewhat narrower form, stronger punctuation, 

 sparser pubescence, and less opacity. The structure of the middle and hinder 

 femora and tibia) of the male appear to be the same as in the same sex of M. 

 hemipterus. 



3. M. SINUATOCOLLIS, Boisd. et Lac, Er., Kr. As the name of this species can 

 hardly fail at times to be confused with that of M. dcnticollis, when quoting from 



