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Psyche 3:53, 1880.

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more abundant than the t> , is yet compar- atively rare. It is of a buff or salmon
color, with eleven segments, pink on their posterior margins, and overlapping. Head narrow, with projecting muzzle, but im-
perfect organs of manducation. Eyes small, round, black, on sides of the head. Anten- nae shorter than thorax, approximate, sit- uated in front of the eye, pale yellow, fee- bly pectinate. Thorax with margin re-
flexed, subrugose. Adjoining the shield
are the rudimentary elytra, semicircular and very small. Feet feeble, compressed ; the body is disproportionately large, and the insect consequently moves with sudden nervous action, and pauses every few steps. Though there are no special phosphores-
cent vesicles visible through the membrane, yet it emits light from the entire ventral surface of the three posterior segments. This is very brilliant, and when less intense posteriorly, appears diffused over the body. This brilliancy continues until oviposition. This <? insect is similar to Packard's illus- tration 428, of an apterous 9 from Mada- gascar, plus the aborted elytra and pectin- ate antennae.
NOTE ON NORTH AMERICAN TRYPETIDAE.
BY CHARLES ROBERT OSTEN SACKEN, HEIDELBERG, GERMANY, Among a number of diptera, collected by
Mr. J. Boll in Dallas, Texas, and purchased by me in Geneva a short time ago, there
were 25 'L and 5' specimens of a Trypeta, bearing on a label " bred from galls on
Ambrosia." The insect could be easily
identified with T. gibba Loew, and as the habits of this species were hitherto un- known, I deem it worth the while to put
Mr. Boll's observation on record.
The gall, which is likewise in the collec- tion, is an oblong swelling of the stem, probably .terminal.
The habits of the following "North Amer- ican Trypeia have been hitherto investi- gated and published (the name of the dis- coverer is in parentheses) : -
Rhagoletis pomonella. -Fruit of the apple-tree ( Walsh).
Oedaspis polita. -Gall on Solidago (0. S.). yibba. -Gall on Ambrosia (Boll).
Eurosta solidaginis. - Gall on Solidago (Harris). Eutreta diana. - Gall on Artemisia tridentata (Riley).
Aspilota alba. - Seeds of Vernonia (Riley). This is a very small number, in compari- son to that of the described N. A. Trypeta ; but the most striking circumstance in con- nection with it is that among six Trypeta, '
whose habits are known, not less than four should occur in galls, and only owe in the heads of a composite flower. In Europe
the Trypeta bred from galls form an imper- ceptible minority, and most of the species are obtained from the heads of composites. Compare, for instance, the list of 60 species bred by Frauenfeld (Verb. k.-k. zoo1.-bot. Gesell. Wien, 1863, p. 221-2241, among
which only three formed galls on the stem of the plant.
It would be worth while for American
entomologists to collect dry heads of com- posite plants in autumn, for the purpose of breeding Trypeta ; a large number of new species of these pretty flies would probably be obtained.
September, 1879.




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