101 



Family Cecidomyidae— The Gall Midges 



Cecidomyida?— Thecodiplosis piniradiatae Snow and Mills. Eggs, pupa, laiA^a, 

 "breast-bone" and imago. (Williston). 



Small, delicate flies with broad wings and long antennae and legs. 



Head small; eyes roinid or reniform, sometimes holoptic; ocelli 

 usually absent; antennas long, cylindrical, the segments usually wath 

 l)ead-like swellings, ten to thirty-six in number; proboscis short, rarely 

 elongated; palpi with one to four segments. Thorax ovate, more or 

 less convex, without transverse suture; abdomen composed of eight seg- 

 ments; hypopygium small but projecting; ovipositor sometimes very 

 long. Legs long and slender; coxiu rather short; tibia; without terminal 

 spurs, Ijasal tarsal segment sometimes very short. Wings large, usually 

 hairy, narrowed ])asally and without alula; three to five longitudinal 

 veins, usually with only the first, third and fifth; humeral crossvein 

 iudisfinct or absent; costal vein extending around the entire wing, the 

 veins all weak, the fifth usually furcate; anterior crossvein situated 

 v('r>- near the base of the wing, often appearing as the beginning of the 

 third vein, the base of the third vein having the appearance of a cross- 

 vein; only one liasal cell present. 



These small flies may be found everywhere but the most satisfac- 

 tory means of collecting them is to rear them. The larva of most of the 

 species live in living plants where they form galls, or deformities of 

 various kinds, in the axils of the leaves, etc. Others live under bark, in 

 decaying vegetation and in fungi while a few live upon plant lice, being 

 found for the most part under the colony of ai)hi(ls or in axils of the 

 leaves during the day. ]Many of the species are iii(|uiliiu's in the galls 

 formed ]\v other members of the family or even by other orders of 

 insects. The galls occur on all parts of plants, on the flowers, leaves, 



