156 



ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



INDIVIDUAL VARIATION IN ADULTS. 



The color of adults shows considerable variation even between 

 parents and offspring. Nine specimens, including the two of the first 



and seven of the sec- 

 ond generation, vary 

 in ground color of the 

 dorsum from a grayish 

 to a reddish brown, 

 and are marked with 

 varying amounts of 

 black. The variation 

 in the form and size in 

 the same series (see 

 fig. 6) is more strik- 

 ing. The humeral an- 

 gles are more acutely 

 produced in the male 

 parent than in any of 

 the other specimens in 

 the series. The males 

 average smaller and 

 show a greater range 

 of variation in size and 

 form than the females. 

 The abundance of food 

 during the nymphal 

 stages is the principal 

 factor which determines the size attained by the adult. Certain 

 measurements have been made of each individual of the nine speci- 

 mens, and are here given in tabular form : 



Variation in form and size of pa)-ciits and offspring. 



Fig. 6.—Podisus maculiventris, variation in form and size of 

 parents and progeny: No. 1, female parent; No. 2, male 

 parent; No. 3, largest specimen of seven of second genera- 

 tion, female ; No. 4, smallest specimen of seven of second 

 generation, male. Enlarged (original). 



