Pocota. 499 



i''/6— 1^/7. It is recorded to frequent the flowers of Grataegus in 

 wooded districts. 



Geographical distribution: — Northern and middle Europe down 

 into Austria and Styria ; towards the north to middle Sweden, and in 

 Finland. 



37. Pocota St. Farg. et Serv. 



This genus is very nearly allied to and similar to Criorrhina. 

 The head is relatively narrower and not so broad as thorax; in the 

 male the eyes are touching for some distance, the vertex consequently 

 less long. Frons bare. The epistoma is eonsiderably hollowed and 

 has no central knob but is very produced at the upper mouth edge, 

 more than the frontal prominence, and it is only slightly descending; 

 the profile is thus quite another than in Criorrhina. The epistoma is 

 black, white pruinose leaving a broad middle line black, in the female 

 nearly all black; it has only hairs just at the eye-margins. Scutellum 

 is black and has no very distinct marginal fringe belov^. Legs simple 

 with the hind femora not thickened. For the rest the species is similar 

 to the shorter and broader species of Criorrhina. 



The developmental stages are known, especially the pupa; it is 

 already described by Schrank (Enumer. Ins. Austr. 1781, 459, 933), who 

 found it "in carie arborum emortuarum", the imago came on ^h. 

 Becher describes likewise the pupa (Wien. ent. Zeitg. I, 1882, 249), which 

 he found in the middle of March in a hollow poplar; the imagines 

 developed in the first eight days of April. Verrall mentions that two 

 specimens in Bigot's collection v^ere bred from pupæ found at the 

 foot of a poplar-tree, and they developed on ^^/s; he has also a note 

 of a specimen bred from a nest of Bomhus terrestis, but naturally he 

 is convinced that here may be some error, Kleine (Ent. Zeitschr. 

 Stuttg. 21, 1907, 191) mentions the larva, found in decaying wood in 

 a Populus pyramidalis in which were fungi ; he thinks the larva feeds 

 on the mycelium; the larvæ pupated in the decaying wood, the imagines 

 came on ^/s-^Vs (I have seen only an abstract of this paper). I have 

 myself examined a pupa, found as larva below the bark on a beech 

 on ^U, it pupated but was dead as pupa on ^^/r,. The pupa is oval, 

 of pale brownish colour, slightly transversely wrinkled; the ventral 

 side is flat and shows seven pairs of prolegs with groups of strong 

 hooks, of these prolegs the first pair are distant from the others and 

 lie near the mouth (Lhus quite as in Eristalis); the anterior dorsal 

 end (the part which is detached by the opening) is somewhat flattened, 

 at the hind margin of it are two short, wart-like, strongly chitinised 

 anterior spiracular tubes. At the posterior end the pupa is abruptly 



32* 



