386 



PSl'CHE. 



[July 1899. 



through the cornfields in swarms Avithout 

 inflicting the slightest injury." 



"When tlie devouring multitudes are at 

 work upon the grass the noise of the grind- 

 ing of their jaws is distinctly audible to the 

 listener as a well defined crackling sound. 



" Over the face of the country traversed 

 by the hosts, their almost complete destruc- 

 tion of tlie grasses leaves the ground looking 

 bare and brown, while ahead of them the 

 hills are fresh and green. The coarser 

 grasses in the "draws" are generally left 

 untouched, as are also the numerous asters, 

 sunflowers, goldenrods, and many other 

 plants." 



"As we left Hugo this afternoon on our 

 way northeast to Arriba, thousands of tliese 

 heavy flyers came dashing into our faces. 

 Our horses were greatly annoyed, and it 

 became necessary' to protect our eyes from 

 the force of the blows inflicted by the num- 

 erous collisions. 



The average rate of travel for the in- 

 dividual was about a mile in six hours ; 



this rate was not maintained through 

 the day- They were most active during 

 the middle of the day and advanced 

 north at the rate of nine iniles in two 

 weeks and south at about the same rate. 

 The eggs from which these hordes 

 came were deposited the previous Au- 

 gust and September by locusts which 

 flew into this area. No internal para- 

 sites were observed. A species of Asi- 

 lidae was noted capturing and killing 

 several individuals. 



These notes are of interest in throw- 

 ing light upon the habits and destructive 

 possibilities of a species of locust up 

 to this time comparatively rare, and 

 therefore considered of little economic 

 importance. The causes which give 

 rise to the sudden appearance in great 

 numbers of a species, classed as rare, 

 are not readily found. Thev are, never- 

 theless, an interesting study. 



LIFE HISTORIES OF NORTH AMERICAN GEOMETRIDAE. — II. 



BY HARRISON G. DYAR, WASHINGTON, D. C. 



Nemoria sttbcroceata Walk. The speci- 

 mens from which eggs were obtained were 

 in poor condition, but Dr. Hulst remarks, "I 

 took this to be a faded specimen of Nemoria 

 siibcroceaiu" and I believe that this determi- 

 nation is correct. I find no previous 

 description of the larva. 



£gS:- Elliptical, flattened above and 

 below, pale green, slightly shining; surface 

 smooth, finely shagreened ; size .6 X .5 X .3 

 ram. Later the color is greenish yellow. 



Siao-e I. Short, with normal feet, the 

 thorax contracted. Head round, pale brown. 



width . 25 mm. Body pale brown, a broad 

 dorsal and fainter narrow subdorsal light red 

 lines; cervical shield and anal plate not 

 differentiated. Feet a little paler than the 

 body, moderate except the anal pair which 

 are large and widely spread laterally. Setae 

 i to V small, black, with large clubbed tips, 

 the tubercles minute; head setae also 

 clubbed; cervical shield area roughened, the 

 tubercles there slightly produced. Later 

 pale ocherous greenish with faint whitish 

 subdorsal and lateral lines. Skin finely 

 reticular shagreened. Still later rusty brown 



