October, '16] ESSIG: CHKYSANTHEMUM GALL-MIDGE 463 



The adults or flies (Fig. 32 E) are exceedingly delicate with noticeably long and 

 slender legs. The head, antennae, thorax and the base of the abdomen are dusky 

 amber; the legs light-amber with light-colored femora; the abdomen bright or pale 

 orange-red; and the eyes very dark-red. The wings are transparent or faintly smoky 

 and covered with many scale-like hairs. The legs are also thickly beset with similar 

 hairs or scales which are noticeably wider at the tip or somewhat spatulate-shaped 

 (Fig. 32 G). The palpi (Fig. 32 M) are two-jointed and the antennae (Fig. 32 H, I, J) 

 are 16-jointed and normally hairy. The body is slender and averages 1.5 mm. in 

 length. 



Life-History 



The habits of the insect have been under observation for only part 

 of a year, but long enough to gain a fair idea of the main points in the 

 life-history. During the summer months of August, September and 

 October the maximum development is reached and there are great 

 numbers of all stages after which there is a gradual reduction until 

 the following spring and summer. The adults of the summer brood 

 give rise to a very large number of maggots ^yhich hibernate in the 

 galls on the leaves and stems of the plants. These reach maturity in 

 the spring and give rise to the summer brood so that there appear to 

 l)e but the two broods during a year. There is some overlapping of 

 the broods since adults may issue as late as January and a few pupae 

 hibernate. The writer has been informed by florists, who have been 

 acquainted with the habits of the insect for years, that the adults 

 swarm in the greenhouses as early as five o'clock in the morning during 

 the summer and that during the day they are not to be found. The 

 former observation has not been substantiated, but the latter was 

 carefully studied and it was found that though the adults could be 

 found at all times during the day they were usually resting on the 

 plants and seldom ever on the wing, though they were seen to fly freely 

 at times but only when disturbed. 



Nature of Work 



As the common name implieS; this insect produces galls which are 

 very characteristic and may be found on the leaves, leaf-petioles, 

 stems and buds of the food plants. The galls (Fig. 32 A, and pis. 34, 35, 

 fig. 2-5) are decidedly cone-shaped and the main axis may be at right- 

 angles or at an acute angle to the main axis of the leaves, stems and 

 buds. Very often they may be almost wholly enclosed within the 

 tissues so that only the tips are exposed. The greatest numbers are 

 to be found on the tender shoots on both sides of the leaves, on the 

 stems near the tips and on the buds. Infested shoots are often dis- 

 torted beyond recognition (PL 35, figure 5) and are eventually killed. 

 The color is first somewhat lighter than the surrounding tissues, but 

 in time become bright red or brown. The size of the fully-developed 



