Ofig [December, 



overlook one all-important fact. In his later work Meigen indicates 

 that he did not know T. culiciformis, and we must therefore assume 

 that at the time he first described Coretlira he had another species under 

 De Geer's name, No doubt this insect was the one he later described as 

 C. lateralis, which is a s3'nonym or A'ariety of C. crystallinvs. 31. cuU- 

 ciformis is abundant in this country in woods in spring, distinguished 

 at once in the adult state from C. crystallinus by the short metatarsi, 

 and in the larva by the very broad head and thorax and the possession of 

 an air-tube. 



BlXINAE. 



Fortunatel}' no question has ever arisen as to the validit}* of the 

 generic name Dixn, and no synon^ym exists. At the present time I am 

 able to recognise ten British species, which can be fairly easily dis- 

 tinguished in the following manner : — 



1. Wings quite clear (sometimes with a faiut cloud on the r-m cross-vein in 



D. aestivalis) 2. 



Wings clouded, at least on the cross-veins and along the basal part of Cu, 



5. 



2. Head largely orange-brown in the middle autumnalis (Mg.) Goet. 



Head mainly or entii-ely blackish 3. 



3. Pleurae, mesosternum, and postnotum usually yellowish : mesonotum with 



three disconnected stripes, the middle one usually double. 



aestivalis Mg. 



Pleurae largely, mesosternum and postnotum entirelj' dark ; mesouotal 

 stripes connected by dark patches, the middle one usually entire. 



4. 



4. Mesonotum yellowish at sides ; the median stripe connected with tlie 



lateral stripes by dark patches in front of the latter, 



lueta (Lw.) Goet. 



Mesonotum mainly shiuing black, the stripes broad and continent, but 

 leaving a lighter area in the middle posteriorly, .amjyhidia De U. 



5. The dark spot over the cross-veins small and rather ill-deiined ; middle 



thoracic stripe undivided; pleurae mottled or unicolorous. 



6. 



This spot very large and shar]ily defined, spjefidiiig upwards filniost to Ei ; 

 middle thoracic stripe divided; pleurae distiucily striped. 



9. 



6. Thorax without grey shimmer ; pleurae nearly unicolorous dark brown ; 



mesonotum with dark pubescence ; between tlie three dark stripes are 

 situated, towards the front, a pair of separate rounded dark spots ; 

 pronotal lobes entirely dark ; wing-spot evenly spread round cress-vein. 



puf)erula Lw. 



Thorax with a grey sLimmer on the pale areas; pleura mottled; meso- 

 notum with pale pubescence ; no separate rounded spots towards front 

 of mesonotum ; ])ronotal lol es pale at the sides; Ming-spot mainly on 

 the inner side of the cross-vein 7. 



