348 
1915, 3 specimens; Muncie, June 3, 1917, and August 15, 1917, two 
specimens ; Augerville, June 6, 1915, 1 specimen; Dubois, May 24 and 
25, 1917, 4 specimens; and Carbondale May 15, 1910, 1 specimen. All 
except the last specimen taken by the writer. 
Larval habits unknown. 
CrYPTOCHAETUM Rondani 
The only species of this genus in North America, iceryae Williston, 
does not occur in Illinois. The species was introduced into California 
from Australia to control the mealy citrus-bug in which the larvae are 
parasitic. In being an internal parasite the species differs from those 
of Leucopis, the larvae of the latter being predaceous. 
ParaALeucoris Malloch 
This genus contains but one species, corvina Malloch, which does 
not occur in Illinois so far as we are aware. 
Larval habits unknown. 
Leucoris Meigen, sens. lat. 
There are at present in the list of North American Diptera seven 
species of the genus Leucopis. A key to six of these was published by 
Dr. A. L. Melander in 1913.* Subsequently Dr. J. M. Aldrich de- 
scribed the seventh speciesf. 
Dr. E. P. Felt recently submitted to me for identification several 
‘specimens which belong to an undescribed species which is represented 
also in the collection of the Natural History Survey, and herein I am 
presenting a key to all the North American species in the hope that by 
so doing I may make it possible for students to identify their specimens 
with more certainty than is possible by using the previously published 
keys. 
I find that there are certain very important chaetotaxic differences 
between some of the species which warrant me in erecting two new sub- 
genera for the reception of two species. It may be that other syste- 
matists will consider these segregates entitled to generic rank, but they 
very closely resemble the species of Leucopis in habitus and markings as 
well as in larval habits and structure, so that from my point of view the 
placing of the species in subgenera is more appropriate than either 
placing them in the same genus or erecting genera for them. 
Key TO SUBGENERA 
1. Thorax with a pair of strong bristles between the posterior pair of dorso- 
centrals (Pl. XLVI, Fig. 4) 
i ee a ic 
* Jour. N, Y: Ent. Soc., Vol. 21, p. 232. 
~ Jour. Econ. Ent., Vol. 7, p. 404. 1914. 
