﻿OF THE STATE ENTOMOLOGIST. 121 



be produced twice a year; i. e. there are two full cycles of development annually. It 

 is quite evident to me, however, that there is no great regularity as to the time of 

 the appearance of either the winged or sexual individuals; or even as to the number of 

 generations intervening between two generations of winged mothers : so much depends 

 on conditions, and the species is so easily influenced in its development by the 

 character of the weather and food conditions. Thus, the vfinged mothers are much 

 more abundant on young trees with tender succulent foliage than on the tougher 

 leaves of the larger trees ; and I am pretty confident that it is no particular generation 

 that hibernates; but that it may be either the first, second, third, etc., from the 

 impregnated Qgg, according as we have early or late cold weather. From August the 

 insects continue to grow and multiply, with decreasing rapidity however, until the 

 leaves commence to turn. The mothers then gradually perish and the young forsake 

 the leaves and crowd around the stems ; this happening in 1874, from the middle to the 

 end of October. 



Whether with this species, as in the case of the Grape, and the European Oak 

 species, some of the wingless, agamous females also lay the sexual eggs precisely as do 

 the winged females, I have not yet ascertained ; though I have no reason to doubt that 

 such will prove to be the case. 



THE KOCKY MOUNTAIN LOCUST-^ Caloptenus spretus Thomas.* 



(Ord., Orthoptera; Fam., AcRiDiD^.f) 



This insect is a fit subject for the close of that portion of the 

 present Report which comes under the head of "Noxious Insects." 

 Few, indeed, are there more noxious than this plague of the West, 

 which in 1874 proved a national calamity, reducing untold thousands 

 to misery and distress. Feeling the importance of the subject, I spent 

 some time in the ravaged districts of Kansas, and carefully studied 

 the habits of the pest as it poured into our western counties. 



ITS NATURAL HISTORY. 



The life-history of this insect is essentially the same as that of the 

 more common locusts that are with us every year. The female, when 

 about to lay her eggs, forces a hole in the ground by means of the 

 two pairs of horny valves which open and shut at the tip of her abdo- 

 men, and which, from their peculiar structure, are admirably fitted 



•The species was named in MS. by Mr. P. R. Uhler, of Baltimore, Md., but never by htm 

 described. Mr. B. D. Walsh subsequently {Pract. Ent. II, p. 1) adopted Mr. Uhler's name in connec- 

 tion with a partial de.^crlption; but Mr. Thomas first IXilly defined the S])ecies, as here distinguished and 

 iieferrcd to by me. The question as to the validity of the species will be discussed in the proper place. 



t Locustidce of Westwood. 



