NO. 1310. NORTH AMERICAN THYSANOPTERA— HINDS. 163 



JIahit((t. — Illinois, Iowa, Maine, Massachusetts, New York, Ohio, 

 Ontario. 



I have soujilit in vain for the males of this species, for although I 

 have mounted over a thousand specimens, and have bred many more 

 in bottles in the laboratory, and have taken and examined large num- 

 bers of them in the held, I have never seen any that 1 even suspected 

 were males. A series of experiments begun in the laboratory in July 

 and continued into December showed that no males are developed in 

 the autumn generations. Experiments were begun the following sea- 

 son by obtaining hibernating females before the weather was warm 

 enough for them to move out of doors and confining them in bottles 

 in the laboratory. These became active and deposited eggs, from 

 which succeeding generations developed without the appearance of 

 any males. 1 conclude, therefore, that this species is parthenogenetic, 

 and reproduces without the intervention of males, at least for a series 

 of generations, in this localitv. 



The following descriptions are of the early stages: 



Eggs. — The eggs are reniform, and vary in length from 0.265 mm. 

 to 0.33 mm. and in width from 0.085 mm. to O.l-tS mm. The average 

 dimensions taken from twenty-five eggs are: Length, 0.288 mm.; 

 width, 0.11 nun. The color is a translucent white. By transmitted 

 light the eggs are seen to be filled with a mass of yolk globules which 

 vary considerably in size. 



Larra. — As the larva emerges from the egg it is very soft, shiny, 

 and nearly white. The eyes are purplish red in color; the appendages 

 are folded closely against the ventral side of the bod3^ The length 

 soon after emergence is about 0.3 mm. and the width is about 0.1 ram. 

 Body tapers from eighth segment to tip; head is nearly as wide as the 

 thorax. Antennte are comparatively large, approximate at base, and 

 composed of seven segments, of which the last four are closely joined 

 and appear almost like a single conical segment; fourth segment is 

 larger than an}" other, and distinctly ringed with whorls of minute 

 hairs; the second and third are indistinctly ringed; basal segment 

 bears one small spine on inner side; two has four spines which are 

 directed forward and one very long spine which is directed backward 

 toward the head; the third bears five short spines, and the terminal 

 part of the fourth and each of the following segments a number of 

 spines, which are quite long and stout. Legs are stout; tarsi one 

 segmented and terminated by two claws. The bladder-like expansion 

 is present. Abdomen much compressed longitudinally and, except the 

 tenth segment, marked with six longitudinal rows of setie, three pairs 

 to each segment. The four dorsal rows also extend forward along the 

 thorax and head; tenth segment })ears six-very long setiu — two dorsal, 

 two lateral, and two ventral. 



The full-grown larva is fusiform, about 1.2 mm. in length and about 

 0.3 mm. in breadth, while the width of head is about 0. 1 mm. Antennie 



