1918] Biology of A gromyza 1 5 



The Pupa. 

 (Plate I, Fig. 8). 



The pupse vary considerably in form and size. A comparison of a 

 number of pupae showed that they varied in length from 3. 10-4. 60 mm., 

 in width from 1 .10-1 .5 mm. , and in thickness from 1 .0-1 .35 mm. Those 

 that are found during the summer and early fall in the base of the leaf 

 are more uniformly shaped being only slightly depressed; while those 

 found later in the gall-forming leaf of the leaf bundle are always decidedly 

 depressed and usually somewhat deformed, so that these pupse in general 

 appearance do not resemble the ones at the bases of the leaves and 

 could be easily mistaken for another species. 



The color of the puparium just after transformation is light brown, 

 but later it becomes dark brown or almost black, especially those in 

 the gall forming leaf; while the other puparia often remain rather light 

 }^ellowish brown in color, though they also vary from dark brown to 

 almost black. 



During the transformation from the larval condition to the puparium, 

 the thoracic and caudal spiracular projections are fully extended and 

 transformed into two pairs of hardened hooks which help in holding 

 the puparium in place in the plant. 



The Adult. 



(Plate I, Fig. 4). 



The adults vary in length from 1.5-2.5 mm. The females are some- 

 what larger than the males. They are characterized by the propor- 

 tionally large wings and the large antennae, the antennae of the males 

 being larger than those of the females. The general ground color is 

 shiny black or at least very dark brown. The thickened veins at the 

 base of the wings, the halterers, proboscis, and joints of the legs are 

 light yellow in color. Other lemon yellow markings occur along the 

 sutures of the thorax and abdomen. The tibia and tarsi are yellowish 

 brown. In the living flies the yellow markings are much more apparent 

 than in the mounted dried specimens. 



A technical description of the adult will be found in the 

 Annals of the Entomological Society of America, VI, 300-301, 

 1913, by J. R. Malloch. 



Specimens were found to be very numerous during the latter 

 part of May till the middle or latter part of June, especially 

 in the swamps and wet places where the iris grows in abundance. 



