2 BULLETIN 833, U. S. DEPARTMENT OF AGRICULTURE. 



twelfth of an inch. When the leaf is affected, the galls usually occur 

 on the upper surface. In such cases a slight swelling often may be 

 observed on the opposite or under side of the leaf. Growth and 

 development of both larva and pupa take place within this gall. 

 When the pupa is fully developed it pushes itself out of the gall, still 

 inclosed in the pupal skin. The latter then splits down the middle 

 of the head and back to allow the adult to emerge. (See PI. II, C.) 

 In the adult stage the midge is a fragile two-winged fly, one- 

 fourteenth inch in length. The abdomen of the male is yellowish 

 orange, while that of the female is reddish orange. The adult on 

 emerging leaves its pupal skin protruding from the opening of the 

 empty gall. (See PI. II, A.) As shown in the life-history studies, 

 the adults emerge after midnight and egg-laying takes place early 

 in the morning. 



HISTORICAL. 



In 1870, E. Perris (1, p. 177) 1 is recorded as having observed ceci- 

 domyiid larvae on Leucanthemum vulgare. Six years later J. E. Von 

 Bergenstamm and P. Low (2) also recorded larvae which in all prob- 

 ability were cecidomyiid, as they were found attacking the young 

 leaves of Chrysanthemum leucanthemum {Leucanthemum vulgare.) In 

 August, 1875, E. Berroyer collected specimens in Eaxalpa, a group of 

 the Eastern Alps of Austria-Hungary, at an elevation of 5,000 feet 

 above sea level. These specimens, which consisted of subterranean 

 galls, and two adult male midges, were submitted to Franz Low (3) 

 by Von Bergenstamm. Frana Low made the original description in 

 1885, which freely translated is as follows: 



Male: Antennae 2-14 jointed. Peduncle shorter than the segments. Terminal 

 segment -with two whorls of stout setae. Wings cloudy white. All veins, also costal 

 vein white. Second parallel vein straight, disappearing in the apex of the wings. 

 First branch of the third parallel vein so weak that it is not visible, unless under best 

 of light and high power, but the wing fold on the other hand is very plainly discernible. 

 Halteres white. Legs with closely adhering hairs, also appearing white. 



Larva : The still unknown larva causes galls on the underground parts of the stem of 

 Chrysanthemum atratum Jacq., in which their complete transformation takes place. 

 In each are also found several larvae, each larva occupying one cell for itself. 



Pupa: The pupa has (like the pupa of the Asphondylia species) three pairs of horns, 

 but on the other hand, lacks the rows of delicate horns foimd on the dorsal surface of 

 abdominal segments of the Asphondylia species. 



The two cephalic horns are very large, widely separated, slender, quite pointed and 

 with the point somewhat recurved. The horns of both other pairs are very small, 

 alike in size and structure, pointed and also with the point somewhat recurved. They 

 occur in such a manner that a horn is located above and below each eye of the pupa ; 

 consequently, the horns of one pair are widely separated from each other. In the cells 

 of the galls in which pupation of the larva takes place, the pupae are so situated that the 

 head points to the periphery of the gall. 



1 Numbers in parentheses refer to " Literature cited," p. 23. 



