142 THE CANADIAN ENTOMOLOGIST. 



some white oak trees ( Qiiercus alba) which stood in a lowland sandy area 

 between two small lakes ; and with them was occasionally seen a wingless 

 male or, more rarely, a wingless female. By August 31 adults were 

 plentiful, always wingless, and the males greatly outnumbered the females. 

 September 2 females were abundant, and one of those taken was 

 macropterous. September 4 two males and a second winged female were 

 found to have matured in a vial which contained pupae taken September 2. 



Acanthothrips nodicornis Reuter. — (PI. VII, fig. 2.) 



This species has long been known as Acanthothrips nodicornis^ but 

 Amyot and Serville's Hoplothrips corticis, dating from 1843, is pro- 

 bably identical with it. The only North American record of the 

 species is that by Franklin (Psyche, Vol. X, p. 222, 1903), who found a 

 single female under loose bark on a sycamore tree at Amherst, Massa- 

 chusetts. My specimens, four females and six males, were taken in an 

 open sandy forest about twelve miles from Baldwin, Michigan. One hot 

 summer's day in August many were seen in copulation on the stump of a 

 young poplar, which two weeks before had been cut for tent stakes ; but 

 when approached they scampered hastily away or dropped at once to the 

 ground and secreted themselves among the fallen leaves. The few taken 

 are all somewhat larger than European examples, averaging nearly one 

 millimeter longer than several specimens (presumably cotypes) received 

 from Prof. Reuter. The drawing and the following description, based on 

 North American examples, may be of use to students of the group. 



Female. — Length about 3 mm. Dorsal surface closely subreticulate ; 

 ventral surface smooth. Colour by reflected light nearly black ; abdo- 

 minal segments 3-8 marked at base with a pair of latero-dorsal white 

 blotches, about equal in size to the secon^ antennal segment. By trans- 

 mitted light the colour is dark blackish brown with maroon pigmentation ; 

 antennal segments i and 2 concolorous with the body, 2 paler at apex ; 

 segments 3-5 with base and apex yellow, intermediate portion blackish 

 brown \ segments 6-8 slightly lighter than body, the base of segment 6 

 yellowish ; legs concolorous with body, excepting tarsi and extremities of 

 tibiae, which are yellowish brown. 



Head one and one-half times as long as wide ; sides subparallel, con- 

 verging slightly to eyes and to base, forming a slight neck-like constriction; 

 dorsal and lateral surfaces sparsely spinose, the lateral spines arising from 

 anterior surface of prominent tubercles, of which about eight are visible 

 on each cheek ; postocular bristles short, blunt, inconspicuous, one-third 



