373 



Family Chyromyidse 



Small flies, the wings sometimes i)ietured. 



Subcosta entire, free and ending in the costa, the costa weakened 

 before its end; postocellar bristles convergent; plates of the orbital 

 bristles extending almost to the anterior border of the front; head 

 higher than long, more or less receding below, the oral margin never 

 conspicuously produced; two pairs of frontal bristles; palpi not large; 

 proboscis short and fleshy; antennae shorter than the face; arista 

 pubescent. I\Iesonotum usually with five pairs of dorsocentrals, two 

 pairs of scutellar bristles; mesopleura with one or more bristles; sterno- 

 pleurals, two to four in a straight line along the upper edge; propleural 

 bristle present. Tibiae usually with preapical bristles. Anal and second 

 basal cells complete; costa with spines. Abdomen rather narrow, bearing 

 bristles on the apices of the segments; genitalia small. 



The species of CJiyromna diifer from those of the other genera in 

 having three pairs of frontal bristles, the anterior pair convergent, 

 four pairs of dorsocentrals and no preapical tibial bristles. There are 

 at least two North American species, flava Linnaeus, and another that 

 is either minima Becker or an undescribed form since it bears only a 

 single pair of dorsocentrals. Some species placed in the genus 

 Aplinniosoma Becker have five pairs of dorsocentrals or tlie number 

 may be reduced to one or two distinct pairs with a row of bristly hairs 

 in front of the suture. These two genera have been placed in a sepa- 

 rate family, based upon the absence of preapical bristles on the tibiae, 

 but I do not see how the family can be maintained. 



I am not well acquainted with the habits of these insects but l^elieve 

 that all are found on foliage near the sea coast and in moist places. The 

 number of known species is not large and most of the American species 

 are soutliern in distribution or occur along the coastal regions. 



^Malloch would unite this family with the Helomyzidffi but the head 

 cliaracters appear to indicate a very distinct difference and I fail to 

 see any really close relationship. Melander included the genera in the 

 Geomyzidae* and keys to the species will be found in liis work. 



1913, Journ. N. Y. Ent. Soc, xxi. pp. 283-300. 



