:\V YORK STATE MUi 



Recognition characters. The injuries briefly described above 

 are the work of small maggots, which are pale greenish while young, 

 later showing the characteristic yellowish or yellowish orange color 

 of gall midge larvae. These irritate the tissues and produce irregular, 

 ovoid swellings, each with a length of about one- twelfth of an inch 

 and very frequently projecting at a rather marked, oblique angle 

 above the normal surface of the affected tissues. A series of these 

 galls side by side result in irregular, confluent swellings. 



One of the easiest methods of detecting the young, inconspicuous 

 galls is to allow the leaf to slip through the loosely closed fingers, 

 a process which will readily disclose the presence of slight swellings. 

 It is particularly desirable to recognize even the smallest galls if an 

 attempt is made to eradicate the insect in a greenhouse, since the 

 transformations occur within the plants. The small developing 

 gall appears as a slight, nodular elevation with a darker center pro- 

 tected to some extent by an unusually abundant mass of short, 

 white hairs, while the fully developed gall has comparatively few 

 of these short hairs and the discolored apical portion makes it 

 relatively conspicuous. The deformations containing insects nearly 

 ready to escape may be recognized by the small, withered, dis- 

 colored, free tip. Scattering galls may occur almost anywhere along 

 the stem, on the petiole of the leaf, on the leaf surface, along the 

 veins of the leaves, and occasionally at the very tip of a lobe. 



Technical description. Egg. Reddish orange, length .15 mm, 

 diameter .03 mm, the extremities narrowly rounded. 



Gall. An irregular, oval, concolorous swelling (plate 13) with a 

 length about 2 mm, usually at a distinct angle to the surface of 

 the plant tissues and frequently causing large, confluent swellings 

 of the stem, leaf or flower head. 



Larva. Length 1 mm, yellowish or yellowish orange when full 

 grown, moderately stout, the extremities rounded; segmentation 

 distinct and the skin smooth. 



Pupa. Length 1.25 mm, stout, narrowly oval, the cephalic 

 horns distinct, conical, the thorax yellowish orange, the wing pads 

 fuscous in pupae nearly ready to transform, the leg cases dark yellow- 

 ish brown, the abdomen a variable orange, narrowly rounded apically. 



Male. Length 1.75 mm. Antennae nearly as long as the body, 

 sparsely haired, fuscous yellowish; 17 or 18 segments, the fifth with 

 a stem about three-fourths the length of the subcylindric basal 

 enlargement, which latter has a length about twice its diameter and 

 a rather thick subbasal whorl of long, stout setae; terminal segment 

 variable, usually somewhat reduced, irregular, elongate, ovate. 

 Palpi; the first segment subquadrate, the second narrowly oval. 

 Mesonotum dark brown, the submedian lines yellowish. Scutellum 

 and postscutellum fuscous yellowish, the abdomen mostly a pale 

 yellowish orange. Wings hyaline, costa light straw, halteres yel- 



