new North-American Insects. 327 



genera at present recognized in North America. It is possible 

 that it may be referable to one of the numerous genera lately 

 proposed for European species allied to Dt'plosis. 



Lasioptera Willistoni, sp. n. 



Gall. — An elongate cylindrical swelling of a twig of Atri- 

 plex canescens, about 35 millim. long and 3| to 4 broad. 



Larva. — Colour pale orange. 



Imago ( ? ). — Length 2§ millim. Black, ornamented with 

 white. Antenna rather stout, cylindrical, not so long as the 

 width of the thorax ; head hardly visible from above, con- 

 cealed by the gibbous thorax ; sides of thorax white, mid- 

 dorsal area whitish ; abdomen with seven pairs of white spots, 

 those of the first pair close together ; tip of abdomen orange. 

 Wings with the costa black, except for a white spot ; fringe 

 black. Legs hoary. 



Hab. Mesilla, New Mexico; also common on the campus 

 of the Agricultural College, Mesilla Park, N.M. 



The imago described emerged May 2, 1897 ; there appears 

 to be a second brood, emerging in August. Great numbers 

 of parasites, determined by Mr. Ashmead as Polygnotus 

 atriplicis, Ashm., have been raised from the galls (collected 

 at Mesilla Park) by Miss Ivah Mead and the present writer. 

 When I first bred this species I was unable to identify it 

 with anything described, so I sent a drawing of it to 

 Dr. "Williston, who informed me that it was a new Lasio- 

 ptera without doubt. Since then I have found two closely 

 allied species, described below. L. Willistoni is the fourth 

 Cecidomyiid found on Atriplex canescens, the other three 

 being Diplosis atriplicicola, sp. n., Asphondylia atriplicis 

 (Twns.), and A. neomexicana (Ckll.j. 



Lasioptera ephedra, sp. n. 



Gall. — A fusiform swelling on twigs of Ephedra trifurca, 

 about 12 millim. long and 5 broad, with a depression on one 

 side subbasally, where the wall is thinner and through which 

 the insect emerges. 



Larva orange. 



Imayo. — Repeated attempts to breed the fly from these 

 galls have been unsuccessful ; but on May 18, 1897, I found 

 what is doubtless the gall-producer hovering over an Ephedra 

 on which were many galls. 



$ . — Length about 2 millim. Differs from L. Willistoni 

 by having the margins of the abdominal segments more or 

 less fringed with white scales, but no well-defined spots. 



23* 



