120 Proceedings of the Biological Society of Washington. 



Chilothrips pini sp. nov. 



Female (macropterous). — Length about 1.4 mm. Color amber-brown, 

 tinged with rufous, with abdominal segments margined at based with a 

 narrow, dark brown line ; antennae slightly paler in the three basal 

 segments, legs paler at articulations ; fore wings brownish drab. 



Head nearly twice as wide as median dorsal length, broadest near base, 

 cheeks nearly straight, slightly diverging Ijehind, anteriorly abruptly 

 rounded to eyes ; occiput with about ten distinct anastomozing lines ; 

 interocellar bristles small and inconspicuous ; other bristles minute. Eyes 

 very minutely setose, shorter than cheeks and only about half as wide as 

 their interval. Ocelli subequal in size, the posterior pair rather widely 

 separated ; pigment red. Antennse three times as long as head, inserted 

 below vertex, formed as in Oxythrips; segment 1 broader than long and 

 about two-thirds the length of 2, which is about two-thirds as wide as 

 long ; apical segments quite slender. Mouth-cone very large and elongate, 

 strictly conical and with sides straight, reaching about one-third across 

 mesosternum. 



Protiiorax fully twice the length of heail, sides straight, very slightly 

 diverging posteriorly, where it is slightly wider than median dorsal length; 

 posterior angles with one pair of short bristles; surface nearly smooth, 

 with a few faint striae near posterior margin. Wings of fore pair pale 

 brownish drab, slightly darker apically ; eosta with about 31 bristles; 

 principal vein with a basal group of about four bristles, a group of three 

 at the fork, and three spaced evenly in apical two-thirds; posterior vein 

 with a nearly equidistant series of about ten, beginning just after the 

 second group of the principal vein. Legs moderately slender ; fore tarsus 

 unarmed on outer lower surface of tip. 



Abdomen slightly wider than pterothorax, smooth; segment 10 acutely 

 conical, longer than ninth, not divided above; bristles moderately long, 

 yellow. 



Measurements of holotype: Length 1.38 mm.; head, length 0.096 mm., 

 width 0.185 mm.; prothorax, length 0.204 mm., width 0.218 mm.; ptero- 

 thorax, widtli 0.271 mm.; fore wing, length 0.900 mm., width near base 

 0.091 mm., at middle 0.061^ mm.; abdomen, width 0.336 mm. 



Antenna! segments : 1 2 



Length (m) 27 42 



Width (M) 34 27 



Total length of antenna, 0.288 mm. 



Described from 42 females, all taken on twigs and leaves of Pinus 

 virginiana, as follows: Bladensburg, Maryland (type locality), April 8, 

 1915 (2 females) [L. O. Jackson] ; Bladensburg, Maryland, April 12, 1915 

 (32 females) [L. O. Jackson, E. R. Kalmbach, and J. D. Hood] ; Dyke, 

 Fairfax County, Virginia, April 15, 1915 (8 females) [L. O. Jackson]. 



The extraordinary mouth-cone of this insect has prevented its assign- 

 ment to the genus Oxythrips, with which it agrees, however, in many 

 details of structure, particularly those pertaining to the antennae and 



