198 DURHAM DIPTERA. 



XXVIII. 300. 



300. Eristalis, Ltr. 



Larvae (Rat-tailed Maggots) live in liquid putrifying mud, 

 &c. 



1 (8). Arista bare. 



2 (5). Scutellum aeneous, like the thorax ; eyes spotted. 



3 (4). Eyes separated in the male, and obviously hairy ; a 



small crumpled-looking species, 8J mm. 



(1568. sepulchralis, L.) 



4 (3). Eyes touching in the male, and almost bare; a neat 



moderate sized species, n mm. 

 1569. Eristalis ceneus, Scop. 

 Hesleden, 1 ?, 31-8-98. 



5 (2). Scutellum yellowish, at least when looked through. 



6 (7). Antennae orange. ( I 57°- cryptarum, F.) 



7 (6). Antennae blackish. 



157 r. Eristalis tenax, L. 

 Very common everywhere. 



8 (1). Arista plumose on at least the basal half. 



9 (10). Very hairy species. 



1572. Eristalis intricarius, L. 

 Hesleden, common. " Killingworth," C. Robson. 



10 (9). Slightly hairy, ground colour shewing distinctly. 



11 (18). Hind femora of the male all black, but sometimes 



pale at the extreme base in the female. 



12 (13). Face in good specimens entirely covered with pale 



dust ; fore and mid tibiae unusually ciliated. 



1573. Eristalis arbustorum, L. 

 Common everywhere. 



13 (12). Face always with a shining black central line or knob. 



14 (15). Fore and mid tarsi all yellow, hind tarsi all blackish. 



1575. Eristalis pertinax, Scop. 

 Common everywhere. 



15 (14). Fore and mid tarsi blackish, or with at the most only 



the base pale. 



