300 Annals Entomological Society of America [Vol. IV, 



which seems to prove that the beetle in question was pure 

 strain. This beetle may possibly have gotten into the cage by 

 mistake in spite of the great care exercised as several dozen 

 cages containing larvae of all the forms were being tended and 

 cleaned daily. 



Five other offspring were reared from humeralis beetles 

 obtained in these experiments, and these all came true, making 

 42 progeny in all reared from humeralis parents, breeding true 

 in every instance. 



Two humeralis beetles without dorsal spots were obtained 

 as the progeny resulting from a cross between a melanopleura 

 male, (evidently a humeralis hybrid) from out of doors, with an 

 anuectans-humeralis female representing the third generation 

 of humeralis reared in the laboratory. All of the ancestors and 

 progeny, two in number, of this female, by a former mating 

 showed the dorsal spots normally developed. These two beetles 

 were the only progeny obtained from this union and efforts to 

 rear offspring from them, though they proved to be male and 

 female, have thus far been fruitless, seemingly due to a weak 

 constitution as the eggs hatch poorly. The male seemed 

 weak and both beetles died soon. It would seem from this case 

 that the absence of these spots dominated over its presence, 

 which is contrary to the behavior of heredity with regard to the 

 other characters of this group. If this is not the case the 

 strain in the laboratory must have carried this character of 

 absence through three generations without it having a chance 

 to meet its equal so as to be able to realize itself. 



Another cross which was made between an annectans male 

 and a humeralis female last August but which laid no eggs 

 until this, the following spring, produced in the first geneartion 

 26 beetles, all annectans. The humeralis female was later used 

 in the first cross represented in the first table in addenda. 



