70 HETEROMERA. [MordefHttertet. 



Emery, Mordellistena i. sp., and Tolida, Mulsant, have been adopted 

 by some authors ; of our six British species, one, M. abdominalis, belongs 

 to Mordellochroa, which appears to be chiefly distinguished by the 

 absence of spurs at apex of intermediate tibiae ; the remainder belong to 

 Mordellistena proper; in several of these, however, the intermediate 

 apical spurs appear to be very minute, or else to be easily broken off, as 

 in several of my specimens I can hardly, if at all, distinguish them. 



The larva ot M. pusilla is found in the stems of Marrubium vulgare (the common 

 horehound) ; it is of a yellowish colour, with rudimentary legs, and covered with 

 shirt black hairs; the apical segment is terminated by a short double black spine; 

 it is found in winter feeding on the pith of the stems ; it changes into a pupa in June, 

 and the imago appears in July (Westwood, Classif. i. p. 294) ; the larva of M. 

 pumila is remarkable for having strongly raised prominences on the front abdominal 

 segments. 



I. Thorax wholly or in part yellowish, yellowish-brown or 



reddish. 



i. Elytra unicolorous black ; thorax of male black with 

 ' base brownish -yellow, of female bright red ; abdomen 



red ; intermediate tibial spurs obsolete and scarcely 



visible (s.g. Mordellochroa, Emery) M. ABDOMINALIS, F. 



ii. Elytra black with yellow patches at shoulders, often 



extended down the sides ; disc of thorax at least dark ; 



abdomen black M. HUMERALIS, L. 



v. lateralis, Ul. 

 iii. Upper surf 'ce entirely yellowish-brown, often obscurely 



darker towards apex of elytra ; under surface con- 



colorous with the upper, or with the abdomen, in part 



at least, darker M. BBUNNEA, F. 



II. Upper and under surface uuicolorous black. 



i. Thorax with the basal margin strongly sinuate on each 

 side, space between sinuation narrow and more strongly 

 produced before scutellum. 



1. Process of pjgidium long and sharp; posterior angles 



of thorax more acutelj produced M. PITMILA, Oyll. 



2. Process of pygidium short and blunt; posterior angles 



of thorax less acutely produced M. BEEVICATTDA, Bon. 



ii. Thorax with the basal margin slightly sinuate on each 

 side, space between sinuation brond and less strongly 

 produced before scutelluui ; posterior singles of thorax 



almost obtuse M. PARVULA, Gyll. 



v. incequalis, Muls. 

 (pusilla, Rt'dt.) 



M. abdominalis, F. ( <$ veniralis, F. ; s. g. Mordellochroa, Emery). 

 Elongate, clothed with fine silky pubescence, very closely and finely 

 sculptured ; thorax broader than long, much narrowed in front, posterior 

 angles obtuse ; scutellum triangular ; elytra gradually narrowed behind, 

 somewhat longer in male than in female ; anal process long and 

 pointed, black with the base red ; claws feebly denticulate. L. 3f-4i 



mm. 



Male black, including thorax, except base, with the mouth, base of 

 antennae, tibial spurs and abdomen red or reddish-testaceous, the latter 

 fuscous in the middle ; anterior femora and tibia? brownish or yellowish- 



