ACROCEBA. 45 



Genus I ACROCERA. 



AcROCERA, Mg. ; Illig. mag. (1806) ; LI. ; Mq. ; Ztt. Syrphus p., Pz. 

 Henops p., Fin. 



Corpus minoris magnituclinis, subglobosum, gibbum, breviter pubescens. 



Color nigi'icans. Oculi nudi, obscure fusci, unicolores. Antennae 



prope verticem insertse. Alse vena tertia longitudinali forcata. 



Body small, gibbous, almost globose, downy. Head small, oval, 

 contracted in front. Eyes bare, almost contiguous. Ocelli 3, on the 

 cro^vn. Proboscis concealed. Antennae small, upright, 3-jointed, 

 seated near the croion ; first joint patelliform ; second cyathiform ; third 

 long, setifonn. Thorax almost round, gibbous, much broader than the 

 head. Wings lanceolate, diverging, oblique, bare ; tldrJ. longitudinal 

 vein forked. Alute large, convex, hiding the httle halteres. Abdomen 

 round, broader and thicker than the thorax, with 5 segments. Legs 

 delicate ; metatarsus as long as the other four joints. 



The Aeroeera are very sluggish^ and are often seated in groups 

 on the withered trunks and branches of oak and other trees, about 

 which they fly when the sun shines in warm weather; they also 

 frequent thickets and herbage beneath trees. 



1. globtdus, Pz. ! fu. xxxvd. 20; LL ; Fhi. ; Mg. ; Mq. ; Ztt. 



Nigra, thoracis lateribus fiavo-macidatis et fasciatis, ahs limpidis, ahdo- 

 minefulvo apice flavo-fasciato, pedibus fulvis. Long. 1|^; alar. 5 Un. 



Black. Head clothed with hoary hairs. Thorax clothed with very 

 short yellow hairs ; a pale yellow spot on each side of the fore border, 

 and a short oblique pale yellow band at the base of each mug. Wings 

 and alulae colourless ; veins and halteres yellow. Abdomen tawny ; an 

 irregular pale yellow band near the tip. Legs tawny ; ungues black. 



Appears during the summer, and frequents the withered 

 branches of the alder, the ash, the aspen, and other trees. (E.) 



2. albipes, Mg. zw. iii. 96. 4 {l%22) .—globulus var.. Pin.; Ztt. 

 Nigra, antenuis fulvis apice nigris, thoracis lateiibus flavo-maculatis et 

 fasciatis, scutello flavo, alls limpidis, abdomine luteo basi nigro-fasciato 

 lateribus nigro-raaculato, pechbus flavis. Long. 1-^2 ; alar. 4-5 lin. 



Black. Head and thorax clothed with pale, very short, yellow hairs. 

 Antennae tawny, black towards the tips. Thorax with a pale yellow 

 spot on each side of the fore border, and with a short obhque pale yellow 

 band at the base of each wing ; scutellum pale yellow. Wings and 

 alulae colourless; veins and halteres yellow. Abdomen luteous ; a black 

 band at the base, and on each side a row of black spots, which successively 

 decrease towards the tip. Legs yellow ; tips of the tarsi black. 



May be a variety of the preceding species. (E.) 



