REPORT OF THE ENTOMOLOGIST. 543 



on the assumption that thej'' represent alternate generations, we 

 should expect the one or the other to coniprise both sexes." 



The history of our experiments with the two forms, in order to as- 

 certain whether or not the relationship suggested in the above para- 

 graph has any real existence, is briefly as follows: 



Grande was first found by Mr. Webster in the summer of 1884, 

 He observed it, and indeed bred it, early in June in Illinois, and on 

 June 6 found females ovipositing in wheat at Oxford, Ind. On tlie 

 7th he found a pupa and a fully developed adult in wheat-stalks. 

 The adults continued abundant until the 18th, when they began to 

 decrease in numbers, and the last one was noticed June 27. A num- 

 ber of the straws in Avhich these females were observed to oviposit in 

 the field were sent to the Department, and a number were retained by 

 Mr. Webster himself. From the straws sent to the Department 

 tritici issued very abundantly in January and February, 1885. With 

 Mr. Webster two premature individuals issued in October, 1884, and 

 others issued in December, 1884, and January, and February, 1885; but 

 all attempts to induce oviposition proved failures. No specimens of 

 grande made their appearance. From straws left outdoors tritici 

 issued in March and April, and again no specimens of grande were 

 seen, although the straws were cut open and thoroughly examined. 



This predisposed us to the conclusion that tritici had developed 

 from eggs laid by grande, and although none of the specimens of 

 tritici thus bred could be induced to oviposit in confinement, the 

 hypothesis of an alternation of the two forms thus received strong 

 support. 



On the 2d of June, 1885, grande was once more observed in con- 

 siderable numbers in a wheat plot, and examination showed this form 

 present in nearly all stages of growth in the stalks. On August 12, 

 1885, stalks were isolated in which grande alone were observed to 

 oviposit, and from these tritici began to issue at Washington Jan- 

 uary 7, 1886, and continued to issue on the following dates: January 

 15, 20, 21, 22, 23, 26, 27, and February 3, 4, 6, and 8, 1886. These all re- 

 fused to oviposit, as was the case the previous Avinter. Mr. Webster 

 was sent South the first of March on another investigation, and on his 

 return to La Fayette in April found a limited number of tritici, which 

 had emerged much later (probably during the latter part of March), 

 still alive in his breeding-cages. 



These specimens he at once transferred, as he states in his report, 

 on the 12th of April, to young wheat plants grown and kept contin- 

 uously under cover in a corner of his garden. These plants were 

 carefully protected from outside insects, and on the 2d of June, 1886, 

 the reverse of the former breeding was accomplished, and grande was 

 bred from wheat in which indubitably nothing but tritici had ovi- 

 posited! Several specimens issued in the next few days, and all im- 

 mediately began to oviposit in the now nearly full-grown straw in 

 other portions of the same stools from which they had issued. 



The next step was then carried out, and these straws, in which the 

 bred specimens of grande had oviposited from June 2 to June 12, were 

 divided, and part sent to Washington and part retained at La Fayette, 

 Ind., by Mr. Webster. On February 4, 1887, two female tritici were 

 bred at Washington, and on the same day, as we subsequently learned, 

 two were bred at La Fayette. 



_ Thus the complete alternation of the two forms has been estab- 

 lished. It will be remembered that the entire absence of a male 

 among the many specimens of both forms bred and collected was a 



