74 CECIDOMYZID^S:. 



ssepissime longiores, articulis longi-pctiolatis, pilis verticillatis longis. 



Abdomen cylindricum, apice forcipatum. Fcem. Antenna? ssepissimc 



breviores, articulorum petiolis brevissimis aut nullis, pilis verticillatis 



brevioribus. Abdomen acuminatum. Oviductus sajpissime elon- 



gatus, nonnunquam lamellis duabus apicalibus. 



Size small or very minute. Head small. Eyes lunate, contiguous 

 on the vertex. Ocelli none. Proboscis short, thick, fleshy. Palpi 

 prominent, curved, four-jointed; first joint smaller than the others; 

 second and third generally of equal length ; fourth most often the 

 longest. Antennae long, often curved upwards, moniliform or filiform, 

 generally with whorls of hairs ; joints from thirteen to thirty-six in 

 number, most often petiolated, simple, or apparently double, in some 

 species alternately long and short. Thorax rounded, occasionally hump- 

 shaped, in a few species prolonged like a hood over the head. Wings 

 ample, broad and rounded at the tips, cuneiform at the base, often pu- 

 bescent or ciliated ; costal vein ending at the tip of the wing or near it 

 on the fore border, or on the hind border ; subcostal about half the 

 length of the wing, or rather longer or shorter, joining the costal 

 at its tip ; cubital generally slightly curved, ending at the tip of the 

 costal, connected with the subcostal by a transverse veinlet, near which 

 it occasionally forms an angle, and in some species undulates from 

 thence to the base; subapical vein almost always wanting; subanal 

 generally distinct, often slight, occasionally obsolete; anal forked, its 

 first or fore branch generally slight, more or less contiguous to the sub- 

 anal vein, obsolete in some species ; second or hind branch generally 

 curved abruptly to the hind border, very rarely obsolete. Halteres 

 long, with large knobs. Abdomen with eight segments in the male, 

 cylindrical and forcipated ; in the female acuminated and with an ovi- 

 duct which varies much in length and shape, and has generally two 

 valves at its tip, when it is short. Legs long, generally very slender ; 

 tibia3 without spines and spurs; first joint of the tarsi very much 

 shorter than the second. 



There are many British species which are different from those 

 here noticed, but with some exceptions I have excluded them, 

 and many of the following descriptions are translated and abridged 

 from the monographs of Winnertz, who has observed the economy 

 of most species, and whose specific characters are much more com- 

 plete than those of any other author on Cecidomyia. Most of the 

 species in the larva state feed on living vegetables, but several 

 inhabit decayed wood, one or two live in oak-apples, and one, ac- 

 cording to Eondani's observations, feeds on Aphides. 



The speceis here described may be grouped thus : 

 a. Anal vein forked. 



b. Transverse veinlet between the base and the tip of the subcostal 

 vein. 

 c. Cubital vein emerging from a flat radicle. 



