• 1868.1 207 
Protini, and would appear to have a varied range of habits ; for, though always 
found by me in fungi, hot-bods, 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 Sa/perda 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 Longicom 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 li 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 paii-) are pitchy-black ; 
the elytra, also, are of a pitchy-brown tinge. The thorax (in the outHne of 
which the principal superficial distinctive chai-acters 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, with 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 tibia? 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 tibise 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 fi-om that species through its legs and the basal 
joints of its antennas being red. It seems also, apart from thoracic characters, to 
differ from M. sinuatocollis in its somewhat narrower form, stronger pimctuation, 
sparser pubescence, and less opacity. The structure of the middle and hinder 
femora and tibiae 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 bo confused with that of 31. denticollis, when quoting from 
