CYRTID^ 417 



VI. CYRTID^. 



Orthorrhaphous brachycerous eremochsetous flies of medium size, but 

 with remarkably inflated bodies, small heads, and gigantic thoracal 

 squamse. 



Fig. 2bii.—Aci-ocvra globalvs S- x 7i. 



Head very small (or even minute) and rounded, almost wholly occupied by 

 the enormous eyes in both sexes, smaller in the female than ni the male but always 

 holoptic. Face very small, placed almost on the underside of the head. Mead 

 entirely without bristles, though more or less pubescent : ocelli three, or tlie 

 front one missing or obsolete, or all three obsolete. Proboscis very variable 

 sometimes exceedingly long, thin, and conspicuous but iiot porrect, and at 

 other times very short, while in some cases the mouth opening seems to be quite 

 closed by a membrane. Palpi usually obsolete. Eyes hairy or bare (bare m all 

 British species), occupying nearly all the head and contiguous m both sexes so that 

 only the small vertical triangle and the small face and mouth stand clear, touching 

 in both sexes for a very long space, in fact usually almost all down the head • tacets 

 all equal in both sexes. Antenna3 three-jointed, or sometimes appearing to be only 

 two-iointed when the basal joint is minute and almost absorbed into the head, usually 

 short, porrect, approximated at the base, and placed m varying positions at about 

 the middle of the head, or at the extreme top near the ocelli, or at the extreme 

 bottom against the mouth; third joint small but transverse and with a quite bare 

 apical arista which is swollen and polished at its base (British species), or elongate 

 and strap-shaped without any style or arista {Panojmue), or short with three apical 



haivs (Fterodontia). . .„, ., ,■ \ i 



Thorax very gibbous ; prothoracic lobes sometimes {P/n/opotrncB) enoYmonsly 

 developed and meeting dorsally so as to form a prolonged shield on the front part ot 

 the thorax : metapleurai bearing a large tuft of fairly long slielter hairs, and some- 

 times produced into a sort of peg or knob. Pubescence usually iairly abundant 

 and sometimes even furry, but without any sign of bristles or long hairs, and 

 sometimes quite minute. Scutellum large, unarmed, and clothed like the thorax ; 

 metanotum usually concealed by the scuteUum. „ , „ , , i n • i 



Abdomen very broad and globose, in fact usually balloon-shaped and pellucid, 

 with about five segments, occasionally contracted on the second and third segments 

 {Meqalyhus) and then with the end knob-like. Pubescence furry, or moderate and 

 rather 'inconspicuous, without any sign of bristles or long hairs. Genitalia in- 

 conspicuous. , . , 1 X- -i.!. 



Legs simple, never long nor thin, entirely without bristles but sometimes with a 

 short blunt spur on the middle tibiffi, or {Astfymella) with almost two spurs on the 

 posterior tibiae and a circlet of very short spines on the front tibia; Pu villi tliree, 

 the empodium being as pad-like as the outer pulviUi ; claws and pulvilli long 



Wings diverging and deflexed when at rest so that they he against the abdomen, 

 longer in the female than in the male, and with a very peculiarly erratic venation in 

 the British species. Ambient vein sometimes not extending even to the wmg-tip. 



