27 



time on a plant which had been free from the insects, as shown by 

 examinations for two or three previons daj^s. The following is the 

 record of M specimens of P. ligata collected in the cotton fields. 

 Each record refers to collection from a single plant when none could 

 be found on near-by plants: August 31, 2; September 1, first plant, 

 ii, second plant, 8; September 2, first plant, 3, second plant, 1; Sep- 

 tember 3, first plant, 2 (male and female), second plant, 5 (3 females, 

 1 male, and 1 escaped) ; September 3, first plant, 1, second plant, 1, 

 third plant, 2 ; September 4, first plant, 1, second plant, 2 ; September 

 G, first plant, 3, second plant, 2, third plant, 3, fourth plant, 2. The 

 average number of bugs per plant in the instances recorded above 

 was 24. In addition to the instances where two or more were found 

 on a single phuit, it might be mentioned that not infrequently after 

 searching for the insects without results one is foinid on each of the 

 two adjacent plants, while, as in the case for single plants referred 

 to above, none could be found on any other plants near by. To 

 determine whether this gregarious tendency is due to sexual attrac- 

 tion or to sight would require more careful attention than it was pos- 

 sil)le to give on the occasion on which these observations were made. 

 Egg laying. — All of the eggs of Pentatoma ligata which were 

 obtained were deposited by females in confinement. They were 

 deposited in batches of from 18 to 43 eggs. One batch was deposited 

 on a mesquite leaf, the others on the bracts of cotton bolls and on cot- 

 ton leaves. It is believed that three and possibly four batches were 

 deposited by the same female. The three batches probably deposited 

 by the insect referred to numbered together 107 eggs. A female pen- 

 tatomid bug of another genus (Podisus) has been known to deposit 

 nearly 500 eggs, a fact which not only gives weight to the supposi- 

 tion that these 107 or more eggs were deposited by the one specimen of 

 P. ligata^ but which indicates that this number does not necessarily 

 give an idea of the maximum number a single feinale may deposit. 



EGGS. 



The following table shows the duration of incubation and the 

 approximate number hatching under indoor conditions, the last four 

 batches being kept most of the time in small pill boxes : 



Egg laying, incubation, and hatching. 



When deposited. 



Number 



of eggs in 



batch. 



When hatched. 



Number 

 hatched. 



Pei'iod of 

 incuba- 

 tion. 



September 4 

 September 6 



Do 



September 7 



Do 



September 10 

 September 14 



do 



September 15 

 do 



Days. 



" Eleven 

 hatched. 



eggs became se[)araied from the batch and were lost before any of thom 



