198 STRATIOMYID^ 



5 (4) Palpi distinct and rather long. Eyes not touching in either sex. 



6 (7) Eyes hairy. Actina. 



7 (6) Eyes bare. 11. Chorisops. 



8 (3) Middle tibiae with two small unequal spurs. Abdomen broad and 



stout. Eyes hairy. Acanthomyia.* 



Actina and Acanthomyia with only one species each might occur in 

 Britain. 



10. BERIS. 



Beris Latreille, Hist. Nat. Crust, et Ins., iii., 447 (1802). 



Rather small flies which are easily recognised by their 

 shape and their peculiarly spined scutellum, as well as by 

 their numerous abdominal segments. 



Head rather semicircular ; face short, pubescent, arched, but little produced. 

 Proboscis prominent and with large sucker-flaps ; palpi rudimentary in the 

 European species (but visible in B. Morrisii). Eyes large and touching (though 

 liardly so in B. Morrisii) for a long space in the male so that in that sex only a 

 small triangular frons and a small elevated vertical space exist, but in the female 

 they are smaller and well separated by an almost parallel-sided frons ; densely hairy 

 in the male (but only sparsely in B. Morrisii), and in that sex the upper and front 

 facets are usually enlarged, but in the female they are less hairy and have no 

 enlarged facets. Antennae porrect, at least almost as long as the head ; two basal 

 joints short, almost equal in length and bearing short bristles ; third joint 

 ( = flagellum) elongate and annulated into eight rings (fig. 148) of which the first and 

 last are longer than the others. 



Fig. 146.— -Bens uaHafa 9 . x 12. 



Thorax rather arched, clothed in the male with rather dense erect pubescence 

 but in the female with shorter more depressed and less conspicuous pubescence, 

 Avithout any trace of bristles or spines. tScutellum (fig. 145) with strong marginal 

 spines which are actual projections of the scutellum itself, as they bear to their tips 

 similar pubescence to that on the disc of the scutellum ; these spines are normally 

 six in number, but vary very much in strength and development, so that there may 

 be any number from four to eight or even nine, as the less developed outer spines 

 may not be symmetrical on both sides. 



Abdomen hardly broader than the thorax, flattened, rather narrow and almost 

 parallel-sided, and consisting of at least seven segments. Genitalia of the male with 

 a pair of elongate dorsal lamellae near together, and a pair of upcurved pickaxe- 

 shaped under lamellae set wide apart with a rather large middle piece between them ; 

 of the female composed of a i^air of projecting two-jointed lamellae. 



Legs simple, except that the basal joint of the hind tarsi is dilated in the male 

 and elongate in both sexes. 



Wings (fig. 146) rather long, being longer than the abdomen • radial vein short 

 and curved upwards so that it ends rather near the subcostal and encloses the 



* The name Hexodonta Rond. cannot claim priority over Acanthomyia Schin. because (1) it was never 

 founded with a known or described species attached to it ; (2) one of its express characters lay in the absence of 

 spurs on any of the tibite ; and (3) the atrocious malformation of the word Exodontha. 



