480 GNATS OR MOSQUITOES — CHAPTER XIV 



Genus XIX. ^DES, Meig. 



(As restricted by Mr. Theobald, Monog. II, p. 224.) 



Meigen's genus originally comprised all species having short 

 palpi in both sexes. These, however, are of such very varying 

 types that, in spite of the small number of species included, the 

 separation of the preceding, and three other genera, has neces- 

 sitated the revision of its definition which, in Mr. Theobald's 

 restricted sense, is limited as follows : — 



" Head clothed with both flat broad, and narrow curved scales, over 

 the occiput, the former always predominating, the latter sometimes 

 nearly absent. Thoi-ax with narrow curved scales ; scutellum usually 

 with four bristles to the mid lobe. Palpi short, apijarenthj two-jointed 

 in both 3 and $ , always much shorter than the proboscis, rounded 

 apically, scaly, and with a few bristles and hairs. Scutellum with narrow 

 curved scales Antenuie fourteen-jointed, plumose in the g , pilose in 

 the 2 , the second joint often rather swollen ; proboscis about the length 

 of the antennie. Wings rather long, the scales much as m Culex, the 

 lateral ones long and slender ; the first sub-marginal cell generally longer 

 and narrower than the second posterior cell, both cells of moderate 

 length. Legs with the ungues of the ? , both equal and toothed and 

 simple, of the J , unequal, the larger toothed, the smaller toothed or 



not so. 



" The essential characters are : (i.) The palpi short in both sexes ; 

 (ii.) the palpi two-jointed ; (iii.) the wings clothed with ordinary scales as 

 in Culex ; (iv.) curved scales only on thorax and scutellum. 



" In regard to the number of joints in the palpi there is some difference 

 of opinion. Ficalbi says they are two-jointed, with a trace of a third 

 joint. I cannot find more than two joints, but there is a basal notch 

 which might be mistaken for a joint." 



They are soberly coloured insects, generally sylvan, and the European 

 forms are said not to bite, though there is some doubt if this applies to 

 the American and African species, and M. Biitleri, from the Malay 

 peninsula, is said to be very troublesome. With the exception of 

 jE. fnsciis, they appear to be rare insects, as the number of specimens 

 received in the Museum has been but small. 



Table of Species of the Genus ^des. 



iii. Abdominal segments with pale basal bands. 



1. Jildes fiiacus, Osten-Sacken. Abdomen dull black, with creamy 



basal bands of crescentic form, 

 vi. Abdominal segments unhanded, but with pale lateral spots. 

 A. Anterior fork-cell longer than the posterior. 



2. ^. Builcri, Theob. Abdomen intensely black, with white lateriil 



patches. Anterior fork-cell twice the length of its stem. 



