Baron Osten Sacken on two new N. A. Cecidomyix. 219 



TWO NEW NORTH AMERICAN CECIDOMYLE. 

 BY BARON R. OSTEN SACKEN. 



In August, 18G6, being in Newport, Rhode Island, I observed a 

 young tree of Gleditchia trfacanthos, the leaves of which were quite 

 conspicuously deformed. The single leaflets were folded in such a way 

 as to assume the appearance of a pod. proportionate to their own size, 

 or of a smaller pod, taking up only a part of the leaflet. (The outer 

 side of the pod was the underside of the leaflet). Each pod contained 

 two or three pale orange larvae of Cecidomyia, with a very delicate, 

 narrow breastbone. About the 10th of August, the gallflies began 

 to escape in large numbers, the pupa-skins remaining attached to the 

 outside of the gall. At the same time I noticed that the young terminal 

 leaves on the branches with their leaflets as yet folded, began to show 

 the characteristic pod-like swelling. This soon led to the discovery, 

 that every one of these young leaflets contained two or three very 

 small* whitish larva? of Cecidomyia, evidently in the first stage of their 

 growth. Were these larvae the produce of the newly escaped gall- 

 flies, which might have inserted their eggs in the fold of the unopened 

 leaflets and thus prevented them from unfolding? This question, as 

 well as the further development of this (apparently) second brood of 

 larvae, I have not been able to investigate. 



The gall seems to be exactly similar to that of Cecid. psettdoacacise, 

 Fitch. (Reports, Vol. I, N. 331). But the gallfly, if Dr. Fitch's 

 description be correct, is evidently different. It belongs to the genus 

 Cecidomyia in the restricted sense of Loew and Wiunertz, as it has the 

 same number of joints in the antennae of both sexes (compare Mono- 

 graphs of the N. A. Diptera, vol. I, p. 175), and, moreover, to the first 

 sub-division of the genus, in which the female antennae have sessile 

 joints. 



Cecidomyia gleditchiee, n. sp. % 9- Head blackish, a small tuft of pale ' 

 hairs on the labrum : antennas 2+12 jointed in both sexes; the % antenna is 

 long enough to reach a little beyond the root of the wing, moniliform (the 

 single joints being connected by short pedicels), verticillate-pilose (the hairs 

 being somewhat longer than the length of the globular joint together with its 

 pedicel) : the 9 antenna? hardly reach beyond the root of the wings: joints sub- 

 globular, sessile and hence, the verticillate character of the pubescence less ap- 

 parent than in the male : hairs also shorter. Thorax blackish, the three strip<-s 



